IPAC2015 - List of Keywords (ion)

Paper	Title	Other Keywords	Page
MOPWA024	Estimation of the Ion Density in Accelerators using the Beam Transfer Function Technique	electron, betatron, synchrotron, impedance	147
	D. Sauerland, W. Hillert ELSA, Bonn, Germany A. Meseck HZB, Berlin, Germany
	Funding: Funded by the federal ministry of education and science of Germany The ELSA stretcher ring of Bonn University serves external hadron physics experiments with a quasi continuous electron beam of up to 3.2 GeV energy. Ions, being generated by collisions of the circulating electrons with the residual gas molecules, accumulate inside the beam potential, causing incoherent tune shifts and coherent beam instabilities. Detailed measurements were carried out in which ion dynamics is studied in dependence of beam energy and current, filling patterns and bias voltages of the ion clearing electrodes. By measuring the beam transfer function using a broadband transversal kicker, we were able to derive an estimate of the average ion density from the shift and broadening of the tune peak. In this contribution first results of these measurements are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA024
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MOPWA025	Simulation of Laser Cooling of Heavy Ion Beams at High Intensities	laser, synchrotron, scattering, simulation	150
	L. Eidam, O. Boine-Frankenheim, D.F.A. Winters GSI, Darmstadt, Germany
	In the past the principle of Doppler laser cooling was investigated and verified in storage rings in the low energy regime. Within the FAIR project the laser cooling will be applied to high intensity and high energy beams for the first time. The laser cooling results in a further increase of the longitudinal phase space density and in non-Gaussian longitudinal beam profiles. In order to ensure stable operation and optimize the cooling process the interplay of the laser force and high intensity effects has to be studied numerically. This contribution will identify constrains of the cooling scheme for an efficient reduction of momentum spread. For high beam energies the scattering of photons has to be treated stochastically instead of using averaged forces. The modeling of the laser force in a particle in cell tracking code will be discussed.
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MOPWA026	Demonstration of Flat Ion Beam Creation and Injection into a Synchrotron	emittance, solenoid, injection, synchrotron	153
	L. Groening, S. Appel, L.H.J. Bozyk, Y. El Hayek, M.T. Maier, C. Xiao GSI, Darmstadt, Germany
	At GSI an ion beam with different horizontal and vertical emittances has been created from a beam with initially equal emittances. This round-to-flat adoption has been accomplished without any beam loss. In the set-up the beam passes through a stripping foil placed inside a solenoid followed by a skewed quadrupole triplet. The amount of beam flatness has been controlled by setting the solenoid field strength only. Increase of the product of the two transverse emittances is purely due to the stripping process that occurs anyway along an ion linac. Beams with different amounts of flatness were injected into a synchrotron applying horizontal multi-turn injection. The efficiency of injection increased as smaller as the horizontal emittance was set by the round-to-flat adaptor.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA026
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MOPWA028	Resonance Compensation for High Intensity Bunched Beams	resonance, space-charge, sextupole, controls	159
	G. Franchetti, S. Aumon, F. Kesting, H. Liebermann, C. Omet, D. Ondreka, R. Singh GSI, Darmstadt, Germany
	Mitigation of periodic resonance crossing induced by space charge is foreseen via classic resonance compensation. The effect of the space charge is, however, not obvious on the effectiveness on the compensation scheme. In this proceeding we report on an experimental campaign performed at SIS18 in an attempt to investigate experimentally the effect of space charge on the resonance compensation. The experimental results and their consequences are discussed through numerical simulations.
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MOPWA036	Status of Injection Studies into the Figure-8 Storage Ring	injection, simulation, experiment, kicker	187
	J.F. Wagner, A. Ates, M. Droba, O. Meusel, H. Niebuhr, D. Noll, U. Ratzinger IAP, Frankfurt am Main, Germany
	The ongoing investigations on the design of the Figure-8 Storage Ring* at Frankfurt University focus on the beam injection. The research includes simulations as well as a scaled down experiment. The studies for an optimized adiabatic magnetic injection channel, starting from a moderate magnetic field up to a maximum of 6 Tesla, with a realistic field model of toroidal coils due to beam dynamics with space charge will be shown. For the envisaged ExB kicker system the simulations deal with beam potential constraints and a multi-turn injection concept in combination with an adiabatic magnetic compression. To investigate the concept of the beam injection into a toroidal magnetic field, a scaled down room temperature experiment is implemented at the university. It is composed of two 30 degree toroidal segments, two volume ion sources, two solenoids and two different types of beam detectors. The experiment is used to investigate the beam transport and dynamics of the laterally injected and “circulating” beam through the magnetic configuration. To set up the injection experiment, theoretical calculations and beam simulations with bender** are used. * M. Droba et al., Proc. of IPAC'14, Dresden, Germany, TUPRO045 ** D. Noll, M. Droba, O. Meusel, U. Ratzinger, K. Schulte, C.Wiesner, Proc. of HB2014, East Lansing, USA, WEO4LR02
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MOPWA047	Start to End Simulation of High Current Injector using TRACEWIN Code	DTL, rfq, optics, linac	223
	S. Kumar, A. Mandal IUAC, New Delhi, India
	High Current Injector (HCI) is an alternate injector to superconducting linac at IUAC in addition to pelletron. It consists mainly of high temperature superconducting ECR ion source (PKDELIS), radio frequency quadrupole (RFQ)* and a drift tube linac (DTL). The ions of mass to charge (A/q) ratio of 6 are analysed initially and accelerated through RFQ and DTL to a total energy of 1.8 MeV/u. The different energy regimes connecting the accelerating stages are named as low, medium and high energy beam transport section (LEBT, MEBT and HEBT). The energy spread of beam increases from 0.02% at ECR source to 0.5% at the DTL exit. An ion beam of normalized transverse and longitudinal emittance of 0.03 pi mm-mrad and 0.3 keV/u-ns has been considered at the start for the simulation of ion optics using TRACEWIN* code. The whole beam transport system has been designed using GICOSY, TRANSPORT and TRACE 3D codes piecewise and TRACEWIN code is used to simulate whole ion optics from start to end including acceleration stages such as RFQ and DTL. Simulation results shows that beam can be injected through LEBT, MEBT and HEBT into LINAC without significant emittance growth and beam loss. * Sugam Kumar et al., Proc. of InPAC-2011, IUAC, New Delhi B.P. Ajith Kumar et al., Proc. of InPAC-2009, RRCAT, Indore * http://irfu.cea.fr/Sacm/logiciels/index3.php
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MOPWA048	Transverse Emittance Measurement for Low Energy Ion Beams Using Quadrupole Scan Method	emittance, plasma, ion-source, ECR	226
	S. Kumar, A. Mandal IUAC, New Delhi, India
	Low energy ion beam facility (LEIBF) * at IUAC consists of all permanent magnet 10 Ghz electron cyclotron resonance (ECR) ion source (NANOGUN) along with 400 kV high voltage accelerating platform, a switching cum analysing magnet and electrostatic quadrupoles. Higher beam currents of heavy charge states and low energy of ion beams puts tremendous challenge to transport the ion beam from source to target. The normalized emittance of analysed ion beam is measured for specific charge to mass ratio using electrostatic quadrupole scan method * for various source parameters like RF power and injection pressure of gas etc. For various m/q ratios, the normalized transverse emittance ranges from 0.1 to 0.6 mm-mrad. It is attributed to beam rotation induced by ECR axial magnetic field, effect of ion temperature in plasma, non linear electric fields and space charge etc which play a significant role in emittance growth. * A. Mandal et. al. Proceedings of IPAC2011, WEPC011, San Sebastián, Spain D Kanjilal et. al. Indian J. Pure Appl. Phys. 39 (2001) 25 * I. G. Brown:The physics and technology of ion sources
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MOPWA052	Formation of a Uniform Ion Beam Based on Nonlinear Focusing and its Applications at the JAEA TIARA Cyclotron	cyclotron, scattering, target, octupole	236
	Y. Yuri, I. Ishibori, T. Ishizaka, S. Okumura, K. Yoshida, T. Yuyama JAEA/TARRI, Gunma-ken, Japan
	A formation/irradiation technique of large-area uniform beams based on nonlinear focusing of multipole magnets has been developed toward advanced research and efficient industrial applications at the TIARA AVF cyclotron of Japan Atomic Energy Agency. The uniform beam is formed as follows: An ion beam extracted from the cyclotron is multiply-scattered with a thin foil so that the transverse beam intensity distribution can be smoothed into a Gaussian-like distribution, critical to the formation of a highly uniform distribution. Then, the tail of the Gaussian-like distribution is folded into the inside by the nonlinear force of octupole magnets and eventually a uniform intensity distribution can be formed on a target. Typically, the area and uniformity of the beam are over 100 cm² and below 10%, respectively. Such large-area uniform beams have already been applied to radiation degradation testing of space-use solar cells and a study on functional materials in TIARA. In the presentation, the latest R&D results and the utilization status of the uniform beam will be shown.
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MOPJE016	Start-to-End Simulation for RAON Superconducting Linac	linac, cryomodule, lattice, emittance	311
	H. Jang, J.-H. Jang, H. Jin IBS, Daejeon, Republic of Korea
	An ion accelerator, RAON is going to be built in Daejeon, Korea by Rare Isotope Science Project(RISP) team in Institute of Basic Science(IBS). The linac part of RAON consists of two low energy linacs, one high energy linac and two bending section for transporting accelerated low energy ions to high energy linac. It is planned to accelerate many diverse ions like proton, carbon, calcium, uranium, etc. which have different A/q values. Consequently the lattice design for each ion and to investigate beam dynamics issues for each case are one of the important topics for this project. For enhancement of beam acceleration a study to suppress emittance growth and to maximize the longitudinal acceptance is conducted while designing the RAON lattice. In this presentation the designed linac lattices for various ions and start-to-end simulation results will be described.
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MOPJE017	Error Analysis and Correction at the Main LEBT of RAON Heavy Ion Accelerator	GUI, rfq, heavy-ion, simulation	314
	H. Jin, I.S. Hong, H. Jang, J.-H. Jang IBS, Daejeon, Republic of Korea
	The main Low Energy Beam Transport (LEBT) section of Rare isotope Accelerator Of Newness (RAON) heavy ion accelerator is designed to transport the ion beams which are generated by Electron Cyclotron Resonance Ion Source (ECR-IS) to the Radio Frequency Quadrupole (RFQ). In the main LEBT, one or two beams are selected among a variety of ion beams to meet the beamline experiment requirements such as beam charge and current. In a uranium beam case, two charge-state, 33+ and 34+, beams are chosen and transported to the RFQ. For transportation of two charge-state beams, beams can be seriously affected by dipole kick or unexpected dispersion caused by magnet errors. These effects of magnet or cavity errors lead to beam loss at the main LEBT or RFQ. Therefore, the effect to the beam orbit and size should be identified and the research for reducing such effect should be required in the main LEBT. In this paper, we will examine the orbit distortion and beam size growth caused by magnet errors and discuss the correction of errors by using correctors and BPMs.
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MOPJE022	Physical Model of Partial RF Discharge in Isochronous Cyclotrons	electron, cyclotron, plasma, ion-source	323
	V.S. Dyubkov MEPhI, Moscow, Russia S. Korenev Siemens Medical Solutions Molecular Imaging, Knoxville, TN, USA
	The physical model for the partial RF discharge - based on the ionization of molecules of residual gas by electron detachment as a result of the electro-dissociation of negative hydrogen ions in isochronous cyclotrons - is proposed in this paper. The result of the simulation of the ionization of gas molecules by these electrons using RF voltage inside the Eclipse cyclotron (kinetic energy of 11 MeV) is presented. The analysis of the conductivity of the RF plasma (partial RF discharge) is given. The influence of the magnetic field on the properties of the partial RF discharge is discussed. The application of this model is for isochronous cyclotrons with low kinetic energy (10^-15 MeV).
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MOPMA005	Non-invasive Beam Profile Monitoring	detector, vacuum, operation, proton	537
	C.P. Welsch, T. Cybulski, A. Jeff, V. Tzoganis, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom T. Cybulski, A. Jeff, V. Tzoganis, C.P. Welsch, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom A. Jeff CERN, Geneva, Switzerland V. Tzoganis RIKEN, Saitama, Japan
	Funding: Work supported by the Helmholtz Association under contract VH-NG-328, the EU under contracts 215080 and 289485, as well as the STFC Cockcroft core grant No. ST/G008248/1. State-of-the-art high energy and high intensity accelerators require new approaches to transverse beam profile monitoring as many established techniques will no longer work due to the high power stored in the beam. In addition, many accelerator applications such as ion beam cancer therapy or material irradiation would benefit significantly from the availability of non-invasive beam profile monitors. Research in the QUASAR Group has focused on this area over the past 5 years. Two different approaches were successfully developed: Firstly, a supersonic gas jet-based monitor was designed and commissioned. It enables the detection of the 2-dimensional transverse beam profile of essentially any charged particle beam with negligible disturbance of the primary beam and accelerator vacuum. Secondly, a monitor based on the Silicon strip VELO detector, originally developed for the LHCb experiment, was tested as an online beam monitor at the Clatterbridge Cancer Center in the UK. The design of both monitors is presented in this contribution. Results from measurements are discussed and complemented by numerical studies into the performance limits of either technique.
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MOPMN007	An Alternate Ring-Ring Design for eRHIC	electron, collider, proton, linac	713
	Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and No. DE-AC02-06CH11357 I present here a new ring-ring design of eRHIC. It utilizes high repetition rate colliding beams and is likely able to deliver the performance to meet the requirements of the science program with low technical risk and modest accelerator R&D. The expected performance includes high luminosities over multiple collision points and a broad CM energy range with a maximum value up to 2×1034 cm^-2s⁻¹ per detector, and polarization higher than 70% for the colliding electron and light ion beams. This new design calls for reuse of decommissioned facilities in the US, namely, the PEP-II high energy ring and one section of the SLAC linac as a full energy injector.
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MOPMN012	SPACE Code for Beam-Plasma Interaction	plasma, simulation, electron, electromagnetic-fields	728
	K. Yu, V. Samulyak SBU, Stony Brook, USA V. Samulyak BNL, Upton, Long Island, New York, USA
	A parallel particle-in-cell code SPACE has been developed for the simulation of electromagnetic fields, relativistic particle beams, and plasmas. The algorithms include atomic processes in the plasma, proper boundary conditions, an efficient method for highly-relativistic beams in non-relativistic plasma, support for simulations in relativistic moving frames, and special data transfer algorithm from the moving to the laboratory frame that collects particles and fields in the lab frame without time shift due to the Lorentz transform, enabling data analysis and visualization. Plasma chemistry algorithms implement atomic physics processes such as the generation and evolution of plasma, recombination of plasma, and electron attachment on dopants in dense neutral gas. Benchmarks and experimental validation tests are also discussed. The code has been used for the simulation of processes relevant to the eRHIC program at BNL and the high pressure RF cavity (HPRF) program at Fermilab.
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MOPMN013	Simulation of Beam-Induced Plasma in Gas Filled Cavities	plasma, simulation, cavity, electron	731
	K. Yu, V. Samulyak SBU, Stony Brook, USA M. Chung UNIST, Ulsan, Republic of Korea B.T. Freemire IIT, Chicago, Illinois, USA V. Samulyak BNL, Upton, Long Island, New York, USA A.V. Tollestrup, K. Yonehara Fermilab, Batavia, Illinois, USA
	Understanding of the interaction of muon beams with plasma in muon cooling devices is important for the optimization of the muon cooling process. SPACE, a 3D electromagnetic particle-in-cell (EM-PIC) code, is used for the simulation support of the experimental program on the hydrogen gas filled RF cavity in the Mucool Test Area (MTA) at Fermilab. We have investigated the plasma dynamics in the RF cavity including the process of power dump by plasma (plasma loading), recombination of plasma, and plasma interaction with dopant material. By comparison with experiments in the MTA, simulations suggest several unknown properties of plasma such as the effective recombination rate, the electron attachment time on dopant molecule, and the ion - ion recombination rate in the plasma.
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MOPMN030	Proton Spin Tracking with Symplectic Integration of Orbit Motion	proton, closed-orbit, resonance, sextupole	766
	Y. Luo, Y. Dutheil, H. Huang, F. Méot, V.H. Ranjbar BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Symplectic integration for orbital motion had been adopted in SimTrack which has been extensively used for dynamic aperture calculation with beam-beam interaction for the Relativistic Heavy Ion Collider (RHIC). Recently spin tracking for protons has been implemented on top of the orbit motion in this code. In this article, we will explain the implementation of spin motion using Thomas-BMT equation, and benchmark with other spin tracking codes currently used for RHIC. Possibility and remedy for very-long term particle tracking, such as on the RHIC energy acceleration, is also explored.
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MOPHA013	Superconducting Radio Frequency Cavity Degradation Due to Errant Beam	cavity, ion-source, linac, vacuum	805
	C.C. Peters, D. Curry, G.D. Johns ORNL RAD, Oak Ridge, Tennessee, USA A.V. Aleksandrov, W. Blokland, M.T. Crofford, C. Deibele, G.W. Dodson, J. Galambos, T.A. Justice, S.-H. Kim, T.A. Pelaia II, M.A. Plum, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05- 00OR22725 for the U.S. Department of Energy. In 2009, the Superconducting Radio Frequency (SRF) cavities at the Spallation Neutron Source (SNS) began to experience significant operational degradation [1]. The source of the degradation was found to be repeated striking of cavity surfaces with errant beam pulses. The Machine Protection System (MPS) was designed to turn the beam off during a fault condition in less than 20 μseconds [2] as these errant beam pulses were not unexpected. Unfortunately an improperly operating MPS was not turning off the beam within the designed 20 μseconds, and the SRF cavities were being damaged. The MPS issues were corrected, and the SRF performance was restored with cavity thermal cycling and RF processing. However, the SRF cavity performance has continued to degrade, though at a reduced rate compared to 2009. This paper will detail further study of errant beam frequency, amount lost per event, causes, and the corrective actions imposed since the initial event.
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MOPHA025	Control System for FRANZ Facility	controls, ion-source, proton, neutron	830
	S.M. Alzubaidi, O. Meusel, U. Ratzinger, C. Wagner IAP, Frankfurt am Main, Germany
	The Frankfurt Neutron Source at the Stern- Gerlach Zentrum (FRANZ) will use the reaction of 7Li(p, n)7Be to produce an intense neutron beam. The neutron energy will be between 10 and 500 keV depending on the primary proton beam, which is variable between 1.8 and 2.2 MeV. A volume type ion source will be used to deliver a 120 keV proton beam with currents up to 200 mA. Like any other facility, FRANZ will need a powerful and reliable control system that also allows monitoring the whole accelerator target areas and experiments. Also interlock and safety systems have to be included to protect personnel from radiation hazards associated with accelerator operations and accompanying experiments. The FRANZ control system is still under development. The ion source will be the first element to be controlled, and to gain experience. A test ion source will be used for testing and examining the performance of this control system. In this paper, the plasma properties, filament ageing and an internal control loop for stable beam production with respect to controlling issues will be discussed.
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MOPHA050	Online Spill Intensity Monitoring for Improving Extraction Quality at CNAO	electron, proton, electronics, extraction	907
	M. Caldara University of Bergamo, Bergamo, Italy J. Bosser, G.M.A. Calvi, L. Lanzavecchia, A. Parravicini, C. Viviani CNAO Foundation, Milan, Italy E. Rojatti UniPV, Pavia, Italy
	The CNAO Foundation is the first Italian center for deep hadrontherapy with Protons and Carbon Ions, performing treatments since September 2011. The extracted beam energy and intensity can vary over a wide range (60-250 MeV for Protons and 120-400 MeV/u for Carbon Ions, 4e6/10¹⁰ pps); the beam intensity uniformity during the slow extraction process is a fundamental requirement for achieving accurate and fast treatments. CNAO developed an online Fast Intensity Monitor (FIM), not perturbing the extracted beam, capable of measuring beam intensity with a bandwidth of 50kHz and a resolution of 1%. It consists of a thin (0.8 μm) metallic foil that emits secondary electrons when traversed by the beam. The electrons are multiplied by a Channeltron device, polarized at high voltage versus ground. The Channeltron output current is amplified and converted in a Pulse Width Modulated (PWM) signal, which is then decoupled and transmitted to the equipment room, where an FPGA implements a servo-spill. The work presents the detector, the floating electronics, the preliminary measurements with beam and the integration in a closed loop on the synchrotron air-core quadrupole obtaining promising results.
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MOPHA051	Scintillating Fibers used as Profile Monitors for the CNAO HEBT Lines	detector, proton, extraction, vacuum	910
	E. Rojatti UniPV, Pavia, Italy J. Bosser, M. Haguenauer, P. Poilleux CERN, Geneva, Switzerland J. Bosser, G.M.A. Calvi, L. Lanzavecchia, A. Parravicini, M. Pullia, C. Viviani CNAO Foundation, Milan, Italy M. Caldara University of Bergamo, Bergamo, Italy
	The CNAO (Centro Nazionale di Adroterapia Oncologica) Foundation is the first Italian center for deep hadrontherapy with Protons and Carbon Ions. Several beam monitors exploiting the scintillation process have been designed to check the beam quality in the extraction lines, in order to guarantee patients safety. The SFH (Scintillating Fibers Harp), the QPM (Qualification Profile Monitor), and the SFP (Scintillating Fibers plus Photodiodes) are made up by two orthogonal scintillating fibers harps with not dead area for the horizontal and the vertical beam profiles measurement. The QPM and the SFH are both installed on the beam line and they use a CCD camera for the signal acquisition. The SFP is a SFH upgrade project aimed to replace the camera with two Photodiodes arrays coupled to the fibers in vacuum. The WD (Watch Dog) detector, not already installed, has been designed to check the beam position through the intensity of the beam tails. It uses two couples of scintillating fibers displaced transversally to the beam direction, coupled to four APDs (Avalanche Photodiodes). This work describes the beam detectors, their achieved performances and the most recent beam measurements.
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MOPTY025	High-current RFQ Design Study on RAON	rfq, emittance, cavity, acceleration	990
	J. Bahng, E.-S. Kim Kyungpook National University, Daegu, Republic of Korea B.H. Choi IBS, Daejeon, Republic of Korea
	Rare isotope Accelerator Of Newness (RAON) heavy ion accelerator has been designed as a facility for a rare isotepe accelerator of the Rare Isotope Science Project (RISP). RAON provides 400 kW CW heavy ion beams from proton to uranium to support researches in various science fields. The RAON system consists of a few ECR ion source, low energy beam transport systems (LEBTs), CW radio frequency quadrupole (RFQ) accelerators, a medium energy beam transport and superconducting linac. We present the design study of the RFQ accelerator from 30 keV/u to 1.5 MeV/u of deuteron beam with meeting a requirement of over 15 mA beam at the target. We optimized the normal conducting CW RFQ accelerator that has a high transmission and a low longitudinal emittance. In this paper, we will present the design result of RFQ beam dynamics studies and its 2D and 3D EM analysis.
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MOPTY082	Beam Instrumentation of the PXIE LEBT Beam Line	emittance, solenoid, ion-source, diagnostics	1129
	R.T.P. D'Arcy UCL, London, United Kingdom B.M. Hanna, L.R. Prost, V.E. Scarpine, A.V. Shemyakin Fermilab, Batavia, Illinois, USA
	The PXIE accelerator is the front-end test stand of the proposed Proton Improvement Plan (PIP-II) initiative: a CW-compatible pulsed H⁻ superconducting RF linac upgrade to Fermilab’s injection system. The PXIE Ion Source and Low-Energy Beam Transport (LEBT) section are designed to create and transfer a 1–10 mA H⁻ beam, in either pulsed (0.001–16 ms) or DC mode, from the ion source through to the injection point of the RFQ. This paper discusses the range of diagnostic tools Allison-type Emittance Scanner, Faraday Cup, Toroid, DCCT, electrically isolated diaphragms – involved in the commissioning of the beamline and preparation of the beam for injection into the RFQ.
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MOPWI003	Laserwire Emittance Scanner at CERN Linac 4	laser, linac, detector, emittance	1146
	K.O. Kruchinin, G.E. Boorman, A. Bosco, S.M. Gibson, P. Karataev Royal Holloway, University of London, Surrey, United Kingdom E. Bravin, T. Hofmann, U. Raich, F. Roncarolo, F. Zocca CERN, Geneva, Switzerland A.P. Letchford STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Linac 4 presently under construction at CERN is designed to replace the existing 50 MeV Linac 2 in the LHC injector chain and will accelerate the beam of high current negative hydrogen ions to 160 MeV. During the commissioning a laserwire emittance scanner has been installed allowing noninvasive measuring of the emittance at 3 MeV and 12 MeV setups. A low power infrared fibre coupled laser was focused in the interaction region down to ~150 um and collided with the ion beam neutralising negative ions. At each transverse laser position with respect to the ion beam the angular distribution of the neutral particle beamlets was recorded by scanning a diamond detector across the beamlet at a certain distance from the IP while the main beam of the H⁻ ions was deflected using dipole magnet installed upstream the detector. Measuring the profile of the beamlet by scanning the laser across the beam allows to directly measure the transverse phase-space distribution and reconstruct the transverse beam emittance. In this report we will describe the analysis of the data collected during the 3 MeV and 12 MeV operation of the Linac 4. We will discuss the hardware status and future plans.
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MOPWI006	Development of a Supersonic Gas-jet Monitor to Measure Beam Profile Non-destructively	vacuum, electron, storage-ring, experiment	1157
	H.D. Zhang, A. Jeff, V. Tzoganis, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom A. Jeff CERN, Geneva, Switzerland A. Jeff, V. Tzoganis, C.P. Welsch, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom V. Tzoganis RIKEN, Saitama, Japan
	Funding: This project is supported by Helmholtz Association(VH-NG-328), EU’s 7th Framework Program for research, technological development and demonstration( 215080) and STFC Cockcroft core grant(ST/G008248/1). The measurement of the transverse beam profile is a great challenge for high intensity, high brightness and high power particle beams due to their destructive power. Current non-destructive methods such as residual gas monitors and beam induced fluorescence monitors either require a rather long integration time or residual gas pressures in the order of 10^-7 mbar to make meaningful measurements. A supersonic gas-jet beam profile monitor has been developed by QUASAR group at the Cockcroft Institute, UK and promises significant improvements over these established techniques. In this monitor, a supersonic gas curtain is generated that crosses the beam to be analyzed under an angle of 45°. When both beams interact, ionization of the gas jet particles occurs and these ions are then accelerated by an electrostatic extraction field towards a Micro Channel Plate (MCP). Beam images are then obtained via a phosphor screen-CCD camera combination. In this contribution, we discuss the monitor design and present beam profile measurements of a 5 keV electron beam. These are complemented by results from measurements using a pulsed valve to study the gas jet dynamics.
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MOPWI009	A Multi-pinhole Faraday Cup Device for Measurement of Discrete Charge Distribution of Heavy and Light Ions	electron, diagnostics, experiment, vacuum	1160
	P.K. Roy, S. Dwaraknath, F.U. Naab, S. Taller, O.F. Toader, G. Was NERS-UM, Ann Arbor, Michigan, USA
	It is a difficult task to identify the beam density distribution profile over discrete areas using a standard Faraday cup, as the measurements are provided for the full aperture geometry of the instrument. Ideally, the intensity of the scintillating material would provide a correlation to the beam density, but the low photon efficiency, damage to the scintillator, and camera resolution all limit the practicality of using this system for assessing the spatial resolution of an ion beam. A beam profile monitor (BPM) device has the ability to provide a partial or discrete distribution of an integrated beam profile. The BPM, however, does not discriminate between ions and electrons, the latter of which can be problematic for assessing the full beam profile. To provide a better description of the beam density in spatial dimensions, a multi-pinhole Faraday cup (MPFC) has been designed, developed, and applied to the measurement of energetic ions. This device uses an array of millimeter sized Faraday cups arranged in a grid to measure the current of the beam at discrete locations. This report presents the design of the device, and its performance with ion beams.
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MOPWI023	Development Plan for Physics Application Software for FRIB Driver Linac	linac, software, EPICS, operation	1201
	M. Ikegami, G. Shen FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. FRIB is a heavy ion linac facility presently under construction at Michigan State University, USA, and its driver linac accelerates CW beams of all stable ions up to uranium to the energy of 200 MeV/u with the beam power of 400 kW. We plan to start beam commissioning of the driver linac from December 2017. An adequate software environment and infrastructure is critical for our commissioning and operation. Recently, a middle layer based architecture, EPICS V4 based services for example, for physics application has been rapidly developed at other facilities like NSLS II. It has been showing its flexibility, and portability. After reviewing those recent developments, we decided to adopt these services as software infrastructure for FRIB driver linac commissioning. It enables us to take advantage of their cutting edge technologies and maturity as a system sustained by the experience accumulated in the commissioning of NSLS-II. In this paper, we present a plan to develop physics application software for FRIB driver linac based on EPICS V4 services and related software. We also present a plan to adjust these EPICS V4 related software to meet the FRIB specific requirements.
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TUXB2	Upgrade of the Unilac for Fair	DTL, proton, linac, emittance	1281
	L. Groening, A. Adonin, R. M. Brodhage, X. Du, R. Hollinger, O.K. Kester, S. Mickat, A. Orzhekhovskaya, B. Schlitt, G. Schreiber, H. Vormann, C. Xiao GSI, Darmstadt, Germany H. Hähnel, U. Ratzinger, A. Seibel, R. Tiede IAP, Frankfurt am Main, Germany
	The UNIversal Linear Accelerator (UNILAC) at GSI serves as injector for all ion species from protons to uranium since four decades. Its 10⁸ MHz Alvarez type DTL providing acceleration from 1.4 MeV/u to 11.4 MeV/u has suffered from material fatigue. The DTL will be replaced by a completely new section with almost same design parameters, i.e. pulsed current of up to 15 mA of 238U²⁸⁺ at 11.4 MeV/u. A dedicated terminal & LEBT for operation with 238U⁴⁺ is currently constructed. The uranium sources need to be upgraded in order to provide increased beam brilliances and for operation at 3 Hz. In parallel a 70 MeV / 70 mA proton linac based on H-mode cavities is under design and construction. This contribution will also give a brief summary of the overall status of the FAIR project.
	Slides TUXB2 [4.634 MB]
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TUYB2	Accelerator Physics in ERL Based Polarized Electron Ion Collider	electron, linac, luminosity, radiation	1296
	Y. Hao BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.
	Slides TUYB2 [14.101 MB]
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TUYB3	Progress on the Design of the Polarized Medium-energy Electron Ion Collider at JLab	electron, collider, polarization, luminosity	1302
	F. Lin, S.A. Bogacz, P.D. Brindza, A. Camsonne, E. Daly, Y.S. Derbenev, D. Douglas, R. Ent, D. Gaskell, R.L. Geng, J.M. Grames, J. Guo, L. Harwood, A. Hutton, K. Jordan, A.J. Kimber, G.A. Krafft, R. Li, T.J. Michalski, V.S. Morozov, P. Nadel-Turonski, F.C. Pilat, M. Poelker, R.A. Rimmer, Y. Roblin, T. Satogata, M. Spata, R. Suleiman, A.V. Sy, C. Tennant, H. Wang, S. Wang, H. Zhang, Y. Zhang, Z.W. Zhao JLab, Newport News, Virginia, USA S. Abeyratne, B. Erdelyi Northern Illinois University, DeKalb, Illinois, USA D.P. Barber DESY, Hamburg, Germany Y. Cai, Y. Nosochkov, M.K. Sullivan, M.-H. Wang, U. Wienands SLAC, Menlo Park, California, USA A. Castilla, J.R. Delayen ODU, Norfolk, Virginia, USA Y. Filatov JINR, Dubna, Russia J. Gerity, T.L. Mann, P.M. McIntyre, N. Pogue, A. Sattarov Texas A&M University, College Station, Texas, USA C. Hyde, K. Park Old Dominion University, Norfolk, Virginia, USA A.M. Kondratenko, M.A. Kondratenko Science and Technique Laboratory Zaryad, Novosibirsk, Russia P.N. Ostroumov ANL, Argonne, Illinois, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. The Medium-energy Electron Ion Collider (MEIC) at JLab is designed to provide high luminosity and high polarization needed to reach new frontiers in the exploration of nuclear structure. The luminosity, exceeding 1033 cm^-2s⁻¹ in a broad range of the center-of-mass (CM) energy and maximum luminosity above 1034 cm^-2s⁻¹, is achieved by high-rate collisions of short small-emittance low-charge bunches made possible by high-energy electron cooling of the ion beam and synchrotron radiation damping of the electron beam. The polarization of light ion species (p, d, 3He) can be easily preserved and manipulated due to the unique figure-8 shape of the collider rings. A fully consistent set of parameters have been developed considering the balance of machine performance, required technical development and cost. This paper reports recent progress on the MEIC accelerator design including electron and ion complexes, integrated interaction region design, figure-8-ring-based electron and ion polarization schemes, RF/SRF systems and ERL-based high-energy electron cooling. Luminosity performance is also presented for the MEIC baseline design.
	Slides TUYB3 [6.245 MB]
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TUBB1	Charge Stripper Development for FRIB	heavy-ion, proton, linac, plasma	1339
	F. Marti, P. Guetschow, J.A. Nolen FRIB, East Lansing, Michigan, USA A. Hershcovitch, P. Thieberger BNL, Upton, Long Island, New York, USA Y. Momozaki, J.A. Nolen, C.B. Reed ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 and NSF grant PHY-1102511 The Facility for Rare Isotope Beams (FRIB) at Michigan State University is building a heavy ion linac to produce rare isotopes by the fragmentation method. The linac will accelerate ions up to U to energies above 200 MeV/u with beam powers up to 400 kW. At energies between 16 and 20 MeV/u the ions will be stripped to higher charge states to increase the energy gain downstream in the linac. The main challenges in the stripper design are due to the high power deposited by the ions in the stripping media (~ 30 MW/cm³) and radiation damage if solids are used. For that reason self-recovering stripper media must be used. The baseline stripper choice is a high-velocity, thin film of liquid lithium with an alternative option of a helium gas stripper. We present in this paper the status of the R&D and construction of the final stripper. Extensive experimental work has been performed on both options.
	Slides TUBB1 [3.534 MB]
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TUBB2	The Accelerator Facility of the Facility for Antiproton and Ion Research	target, proton, antiproton, heavy-ion	1343
	P.J. Spiller, F. Becker, A. Dolinskyy, L. Groening, O.K. Kester, K. Knie, H. Reich-Sprenger, W. Vinzenz, M. Winkler GSI, Darmstadt, Germany D. Prasuhn FZJ, Jülich, Germany
	The accelerators of the Facility for Antiproton and Ion Research – FAIR are under construction. The sophisticated system of accelerators is designed to produce stable and secondary beams with a significant variety of intensities and beam energies. FAIR will explore the intensity frontier of heavy ion accelerators and the beams for the experiments will have highest beam quality for cutting edge physics to be conducted. The main driver accelerator of FAIR will be the SIS100 synchrotron. In order to produce the intense rare isotope beams (RIB) at FAIR, a unique superconducting fragment separator is under construction. A system of storage rings will collect and cool secondary particles from the FAIR. Intense work on test infrastructure for the huge number of superconducting magnets of the FAIR machines is ongoing at GSI and several partner labs. In addition, the GSI accelerator facility is being prepared to serve as injector for the FAIR accelerators. As the construction of the FAIR accelerators and the procurement has started, an overview of the designs, procurements plans and infrastructure preparation can be provided.
	Slides TUBB2 [4.653 MB]
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TUPJE079	High Charge Development of the APS Injector for an MBA Upgrade	booster, impedance, vacuum, injection	1828
	C. Yao, M. Borland, J.R. Calvey, K.C. Harkay, D. Horan, R.R. Lindberg, N. Sereno, H. Shang, X. Sun, J. Wang ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The APS MBA (multi-bend achromat) upgrade storage ring will employ a “swap out” injection scheme and requires a single-bunch beam with up to 20 nC from the injector. The APS injector, which consists of a 450-MeV linac, a particle accumulator ring (PAR), and a 7-GeV synchrotron (Booster), was originally designed to provide up to 6 nC of beam charge. High charge injector study is part of the APS upgrade R&D that explores the capabilities and limitations of the injector through machine studies and simulations, and identifies necessary upgrades in order to meet the requirements of the MBA upgrade. In the past year we performed PAR and booster high charge studies, implemented new ramp correction of the booster rap supplies, explored non-linear chromatic correction of the booster, etc. This report presents the results and findings.
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TUPMA023	Two-Dimensional Calculation of Channeling Radiation Spectrum for High-Brightness Hard X-Ray Production	electron, radiation, lattice, brightness	1888
	W.D. Rush, J. Shi KU, Lawrence, Kansas, USA
	The channeling radiation spectrum is calculated without using the one-dimensional approximation in the planar channeling radiation model or the single-string approximation in the axial channeling radiation model. The obtained spectrum of the two-dimensional channeling radiaiton is significantly different from those previously calculated with the approximations. The calculation presented here is of the channeling radiation experiments conducted at Fermilab Advanced Superconducting Test Accelerator (ASTA) photoinjector with electron beam energies of 20-50 MeV and a diamond target. The computational method developed in this work can be applied to general cases of different crystals and beams with different energy and emittances.
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TUPHA012	LOCO Application to NSLS2 SR Dispersion and Beta Beating Correction	quadrupole, optics, storage-ring, lattice	1989
	X. Yang BNL, Upton, Long Island, New York, USA X. Huang, J.A. Safranek SLAC, Menlo Park, California, USA
	During the short run in early July, 2014, we made changes to the Matlab LOCO setup for NSLS-II and applied LOCO successfully to the machine. The MML setup was verified with I/O tests for all quadrupole families. The LOCO setup was further tested with an intentional quadrupole error. After the successful LOCO correction, the rms beta beat was reduced from the initial values of 5.5% x and 5.6% y, to 1.9% x and 1.0% y, respectively. The rms horizontal dispersion error was reduced from 21 mm to 6 mm. It is critical to keep the same closed orbit for LOCO correction to take effect. Because presently some correctors are nearly saturated, closed orbit cannot be controlled for additional iterations. We expect LOCO to achieve better optics correction after the orbit control is improved.
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TUPTY025	Betatron Cleaning for Heavy Ion Beams with IR7 Dispersion Suppressor Collimators	proton, heavy-ion, collimation, simulation	2057
	P.D. Hermes, R. Bruce, J.M. Jowett, S. Redaelli CERN, Geneva, Switzerland
	The betatron collimators in IR7 constitute the backbone of the collimation system of the LHC. A fraction of the secondary halo protons or heavy-ion fragments, scattered out of the primary collimator, is not captured by the secondary collimators but hit cold magnets in the IR7 dispersion suppressor (DS) where the dispersion starts to increase. A possible approach to reduce these losses is based on the installation of additional collimators in the DS region. In this paper, simulations of the cleaning efficiency for Pb⁸²⁺ ions are used to evaluate the effect of the additional collimators. The results indicate a significant improvement of the heavy-ion cleaning efficiency.
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TUPTY028	Collimator Layouts for HL-LHC in the Experimental Insertions	collimation, luminosity, proton, heavy-ion	2064
	R. Bruce, F. Cerutti, L.S. Esposito, J.M. Jowett, A. Lechner, E. Quaranta, S. Redaelli, M. Schaumann, E. Skordis, G.E. Steele CERN, Geneva, Switzerland H. Garcia Morales, R. Kwee-Hinzmann JAI, Egham, Surrey, United Kingdom
	This paper presents the layout of collimators for HL-LHC in the experimental insertions. On the incoming beam, we propose to install additional tertiary collimators to protect potential new aperture bottlenecks in cells 4 and 5, which in addition reduce the experimental background. For the outgoing beam, the layout of the present LHC with three physics debris absorbers gives sufficient protection for high-luminosity proton operation. However, collisional processes for heavy ions cause localized beam losses with the potential to quench magnets. To alleviate these losses, an installation of dispersion suppressor collimators is proposed.
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TUPTY047	ERL with Non-Scaling Fixed Field Alternating Gradient Lattice for eRHIC	electron, linac, hadron, collider	2120
	D. Trbojevic, J.S. Berg, S.J. Brooks, Y. Hao, V. Litvinenko, C. Liu, F. Méot, M.G. Minty, V. Ptitsyn, T. Roser, P. Thieberger, N. Tsoupas BNL, Upton, Long Island, New York, USA
	Funding: Work performed under Contract Number DE-AC02-98CH10886 with the auspices of the US Department of Energy. The proposed eRHIC electron-hadron collider uses a "non-scaling FFAG" lattice to recirculate 16 turns of different energy through just two beamlines located in the RHIC tunnel. This paper presents lattices for these two FFAGs that are optimised for low magnet field and to minimise total synchrotron radiation across the energy range. The higher number of recirculations in the FFAG allows a shorter linac (1.322GeV) to be used, drastically reducing cost, while still achieving a 21.2GeV maximum energy to collide with one of the existing RHIC hadron rings at up to 250GeV. eRHIC uses many cost-saving measures in addition to the FFAG: the linac operates in energy recovery mode, so the beams also decelerate via the same FFAG loops and energy is recovered from the interacted beam. All magnets will constructed from NdFeB permanent magnet material, meaning chillers and large magnet power supplies are not needed. This paper also describes a smaller prototype ERL-FFAG accelerator that will test all of these technologies in combination to reduce technical risk for eRHIC.
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TUPTY078	Fixed-energy Cooling and Stacking for an Electron Ion Collider	electron, ECR, space-charge, collider	2214
	P.M. McIntyre, S. Assadi, J. Gerity, A. Sattarov Texas A&M University, College Station, Texas, USA
	The proposed designs for polarized-beam electron-ion colliders require cooling of the ion beam to achieve and sustain high luminosity. One attractive approach is to make a fixed-energy storage ring in which ions are con-tinuously cooled and stacked during a collider store, then transferred to the collider and accelerated for a new store when the luminosity decreases. An example design is reported for a 6 GeV/u superferric storage ring, and for a d.c. electron cooling system in which electron space charge is fully neutralized so that high-current magnetized e-cooling can be used to best advantage.
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TUPTY082	Scanning Synchronization of Colliding Bunches for MEIC Project	cavity, controls, electron, collider	2229
	Y.S. Derbenev, V.P. Popov JLab, Newport News, Virginia, USA Y.D. Chernousov ICKC, Novosibirsk, Russia G.M. Kazakevich Euclid TechLabs, LLC, Solon, Ohio, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Synchronization of colliding beams is one of the major issues of an electron-ion collider (EIC) design because of sensitivity of ion revolution frequency to beam energy. A conventional solution for this trouble is insertion of bent chicanes in the arcs space. In our report we consider a method to provide space coincidence of encountering bunches in the crab-crossing orbits Interaction Region (IR) while repetition rates of two beams do not coincide. The method utilizes pair of fast kickers realizing a bypass for the electron bunches as the way to equalize positions of the colliding bunches at the Interaction Point (IP). A dipole-mode warm or SRF cavities fed by the magnetron transmitters are used as fast kickers, allowing a broad-band phase and amplitude control. The proposed scanning synchronization method implies stabilization of luminosity at a maximum via a feedback loop. This synchronization method is evaluated as perspective for the Medium Energy Electron-Ion collider (MEIC) project of JLab with its very high bunch repetition rate.
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TUPWI003	Proton Beam Applications for Silicon Bulk Micromachining	proton, experiment, linac, quadrupole	2241
	P. Nenzi, G. Bazzano, F. Marracino, L. Picardi, C. Ronsivalle, V. Surrenti, M. Vadrucci ENEA C.R. Frascati, Frascati (Roma), Italy F. Ambrosini University of Rome La Sapienza, Rome, Italy F. Ambrosini Università di Roma "La Sapienza", SAPIENZA-DIET, Roma, Italy M. Balucani, A. Klyshko University of Rome "La Sapienza", Rome, Italy C. Snels, M. Tucci ENEA Casaccia, Roma, Italy
	The irradiation of silicon with ion beams is an established technique to modify its properties. Protons are used for micromachining applications, in conjunction with porous silicon. Porous silicon does not form in areas irradiated with a given fluence of protons (>10¹⁴ cm^-2). Our work concentrated on the applicability of masked irradiation of silicon wafers with 1.8 MeV proton beams delivered by the TOP-IMPLART LINAC. In our experiments 1-10 Ω*cm n,p-type silicon wafers were masked and irradiated with protons at fluences between 10¹⁴ and 10¹⁵ protons/cm². Porous silicon did not form in the irradiated areas up to a distance from the surface corresponding to the stopping range (30um). The suppression of porous silicon formation is due to the to the neutralization of dopant impurities by implanted protons that increases the local resistivity. The interest in using RF LINAC for micromachining applications lies in the possibility of deep implantation, that allows the realization of 3D structures for MEMS applications. The use of metal masks with uniform beams, instead of scanned micro- and nano-metric ion probes, increases throughput achievable in industrial processing of wafers.
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TUPWI021	Progress on a 30 - 350 MeV Normal-Conducting Scaling FFAG for Proton Therapy	proton, lattice, injection, extraction	2285
	J.M. Garland, R.B. Appleby, H.L. Owen, S.C. Tygier UMAN, Manchester, United Kingdom
	Funding: Work supported by the STFC (UK) under grant no. ST/K002503/1 We present our progress on a new design for a 30 - 350 MeV scaling FFAG for proton therapy and tomography - NORMA (NOrmal-conducting Racetrack Medical Accelerator) which allows the realisation of proton computed tomography (pCT) and utilises normal conducting magnets in both a circular and racetrack configuration which are designed using advanced optimisation algorithms developed in PyZgoubi. The ring and racetrack configurations have average circumferences of around 60 and 70 m respectively, peak magnetic fields of < 1.8 T, average orbit excursions < 50 cm and dynamic aperture calculations of > 50 mm.mrad using a novel technique. The racetrack design has a total magnet-free straight length of 4.9 m at two opposing points, designed to ease injection and extraction systems.
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TUPWI029	Baseline Scheme for Polarization Preservation and Control in the MEIC Ion Complex	polarization, collider, controls, solenoid	2301
	V.S. Morozov, Y.S. Derbenev, F. Lin, Y. Zhang JLab, Newport News, Virginia, USA Y. Filatov MIPT, Dolgoprudniy, Moscow Region, Russia A.M. Kondratenko, M.A. Kondratenko Science and Technique Laboratory Zaryad, Novosibirsk, Russia
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. The scheme for preservation and control of the ion polarization in the Medium-energy Electron-Ion Collider (MEIC) has been under active development in recent years. The figure-8 configuration of the ion rings provides a unique capability to control the polarization of any ion species including deuterons by means of "weak" solenoids rotating the particle spins by small angles. Insertion of "weak" solenoids into the magnetic lattices of the booster and collider rings solves the problem of polarization preservation during acceleration of the ion beam. Universal 3D spin rotators designed on the basis of "weak" solenoids allow one to obtain any polarization orientation at an interaction point of MEIC. This paper presents the baseline scheme for polarization preservation and control in the MEIC ion complex.
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TUPWI031	Status of the MEIC Ion Collider Ring Design	electron, collider, dipole, optics	2307
	V.S. Morozov, Y.S. Derbenev, L. Harwood, A. Hutton, F. Lin, F.C. Pilat, Y. Zhang JLab, Newport News, Virginia, USA Y. Cai, Y. Nosochkov, M.K. Sullivan, M.-H. Wang, U. Wienands SLAC, Menlo Park, California, USA J. Gerity, T.L. Mann, P.M. McIntyre, N. Pogue, A. Sattarov Texas A&M University, College Station, Texas, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported in part by the US DOE Contract No. DE-AC02-76SF00515. We present an update on the design of the ion collider ring of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The design is based on the use of super-ferric magnets. It provides the necessary momentum range of 8 to 100 GeV/c for protons and ions, matches the electron collider ring design using PEP-II components, fits readily on the JLab site, offers a straightforward path for a future full-energy upgrade by replacing the magnets with higher-field ones in the same tunnel, and is more cost effective than using presently available current-dominated super-conducting magnets. We describe complete ion collider optics including an independently-designed modular detector region.
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TUPWI032	Progress on Optimization of the Nonlinear Beam Dynamics in the MEIC Collider Rings	sextupole, optics, distributed, dynamic-aperture	2311
	Y. Nosochkov, Y. Cai, M.K. Sullivan, M.-H. Wang, U. Wienands SLAC, Menlo Park, California, USA Y.S. Derbenev, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under US DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported by the US DOE Contract DE-AC02-76SF00515. One of the key design features of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab is a small beta function at the interaction point (IP) allowing one to achieve a high luminosity of up to 10³⁴ cm^-2s^-1. The required strong beam focusing unavoidably causes large chromatic effects such as chromatic tune spread and beam smear at the IP, which need to be compensated. This paper reports recent progress in our development of a chromaticity correction scheme for the ion ring including optimization of dynamic aperture and momentum acceptance.
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TUPWI034	Capture, Acceleration and Bunching RF Systems for the MEIC Booster and Storage Rings	cavity, collider, electron, bunching	2318
	S. Wang, J. Guo, F. Lin, V.S. Morozov, R.A. Rimmer, H. Wang, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 The MEIC, proposed by Jefferson Lab, consists of a series of accelerators. The electron collider ring accepts electrons from CEBAF at energies from 3 to 12 GeV. Protons and ions are delivered to a booster and captured in a long bunch before ramping and transfer to the ion collider ring. The ion collider ring accelerates a small number of long ion bunches to colliding energy before they are re-bunched into a high frequency train of very short bunches for colliding. Two sets of low frequency RF systems are needed for the long ion bunch energy ramping in the booster and ion collider ring. Another two sets of high frequency RF cavities are needed for re-bunching in the ion collider ring and compensating synchrotron radiation energy loss in the electron collider ring. The requirements from energy ramping, ion beam bunching, electron beam energy compensation, collective effects, beam loading and feedback capability, RF power capability, etc. are presented. The preliminary designs of these RF systems are presented. Concepts for the baseline cavity and RF station configurations are described, as well as some options that may allow more flexible injection and acceleration schemes.
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TUPWI035	MEIC Proton Beam Formation with a Low Energy Linac	booster, collider, linac, proton	2322
	Y. Zhang JLab, Newport News, Virginia, USA
	The MIEC proton and ion beams are generated, accumulated, accelerated and cooled in a new green-field ion injector complex designed specifically to support its high luminosity goal. This injector consists of sources, a linac and a small booster ring. In this paper we explore feasibility of a short ion linac that injects low energy protons and ions into the booster ring.
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TUPWI037	Electron Cooling Study for MEIC	electron, proton, emittance, solenoid	2326
	H. Zhang, Y.S. Derbenev, D. Douglas, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and No. DE-AC02-06CH11357. Electron cooling of the ion beams is one critical R&D to achieve high luminosities in JLab’s MEIC proposal. In the present MEIC design, a multi-staged cooling scheme is adapted, which includes DC electron cooling in the booster ring and bunched beam electron cooling in the collider ring at both the injection energy and the collision energy. We explored the feasibility of using both magnetized and non-magnetized electron beam for cooling, and concluded that a magnetized electron beam is necessary. Electron cooling simulation results for the newly updated MEIC design is also presented.
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TUPWI038	A High Energy e-p/A Collider Based on CepC-SppC	proton, electron, collider, luminosity	2329
	Y. Zhang JLab, Newport News, Virginia, USA Y.M. Peng IHEP, Beijing, People's Republic of China
	Construction of CepC and SppC, the proposed future energy frontier circular e⁺e⁻ and pp colliders in China, provides an opportunity to realize e-p or e-A collisions in a CM energy range up to 4.1 TeV. This paper presents a preliminary conceptual design of this e-p/A collider. The design parameters and anticipated luminosities will be given. We also discuss staging approaches to realize this collider with a low cost and at an earlier time.
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TUPWI039	Modeling Crabbing Dynamics in an Electron-Ion Collider	electron, proton, betatron, collider	2333
	A. Castilla, J.R. Delayen, T. Satogata ODU, Norfolk, Virginia, USA A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata JLab, Newport News, Virginia, USA A. Castilla DCI-UG, León, Mexico
	Funding: *Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A local crabbing scheme requires π/2 (mod π) horizontal betatron phase advances from an interaction point (IP) to the crab cavities on each side of it. However, realistic phase advances generated by sets of quadrupoles, or Final Focusing Blocks (FFB), between the crab cavities located in the expanded beam regions and the IP differ slightly from π/2. To understand the effect of crabbing on the beam dynamics in this case, a simple model of the optics of the Medium Energy Electron-Ion Collider (MEIC) including local crabbing was developed using linear matrices and then studied numerically over multiple turns (1000 passes) of both electron and proton bunches. The same model was applied to both local and global crabbing schemes to determine the linear-order dynamical effects of the synchro-betatron coupling induced by crabbing.
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TUPWI051	Study of Orbit Correction for eRHIC FFAG Design	lattice, simulation, electron, alignment	2366
	C. Liu, Y. Hao, V. Litvinenko, F. Méot, M.G. Minty, V. Ptitsyn, D. Trbojevic BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The chromaticities in the eRHIC linear non-scaling Fixed Field Alternating Gradient (FFAG) lattice are very large. Therefore, particles will decohere in phase space given the presence of lattice errors. The decoherence causes a deviation of the orbit response which is the basis for orbit corrections. In this report we will present a study of the linearity of the orbit response in a lattice with large chromaticity, a comparison of the results of orbit corrections for several cases together with a conclusion that correcting the average orbit with a measured orbit response works as good as an orbit correction for on-momentum particles. The work was performed under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
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TUPWI059	Influence of Plasma Loading in a Hybrid Muon Cooling Channel	plasma, electron, cavity, emittance	2381
	D. Stratakis BNL, Upton, Long Island, New York, USA B.T. Freemire IIT, Chicago, Illinois, USA K. Yonehara Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In a hybrid 6D cooling channel, cooling is accomplished by reducing the beam momentum through ionization energy loss in wedge absorbers and replenishing the momentum loss in the longitudinal direction with gas-filled rf cavities. While the gas acts as a buffer to prevent rf breakdown, gas ionization may also occur as the beam passes through a HPRF cavity. The resulting plasma, may gain substantial energy from the rf electric field which it can transfer via collisions to the gas, an effect known as plasma loading. In this paper, we investigate the influence of plasma loading on the cooling performance of a rectilinear hybrid channel. With the aid of numerical simulations we examine the sensitivity in cooling performance and plasma loading to key parameters such as the rf gradient and gas pressure.
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WEXC1	Machine and Personnel Protection for High Power Hadron Linacs	linac, radiation, hadron, controls	2418
	M. Ikegami FRIB, East Lansing, Michigan, USA
	Machine and personnel safety are increasingly important for high power hadron linacs as involved beam power increases. Design requirements and characteristic features of machine protection system and personnel protection system for operating and proposed high power hadron linacs, such as J-PARC, SNS, FRIB, ESS, and IFMIF, are reviewed.
	Slides WEXC1 [9.859 MB]
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WEPWA012	Design of a Microwave Frequency Sweep Interferometer for Plasma Density Measurements in ECR Ion Sources	plasma, simulation, diagnostics, ion-source	2512
	G. Torrisi, R. Agnello, G. Castro, L. Celona, V. Finocchiaro, S. Gammino, D. Mascali, L. Neri, S. Passarello INFN/LNS, Catania, Italy T. Isernia, G. Torrisi Universitá Mediterranea di Reggio Calabria, Reggio Calabria, Italy G. Sorbello University of Catania, Catania, Italy
	Electron Cyclotron Resonance Ion Sources (ECRIS) are among the candidates to support the growing request of intense beams of multicharged ions. Their further development is related to the availability of new diagnostic tools, nowadays consisting of few types only of devices designed on purpose for such compact machines. Microwave Interferometry is a non-invasive method for plasma diagnostics and represents the best candidate for the whole plasma density measurements. Interferometry in ECR Ion Sources is a challenging task due to their compact size. The typical density range of ECR plasmas (10¹¹-10¹² cm^-3) causes the probing beam wavelength to be in the order of few centimetres, which is comparable to the chamber radius. The paper describes the design of a new microwave interferometer based on the so-called "frequency sweep" method: the density is here derived by the frequency shift of a beating signal obtained during the fast sweep of both probing and reference microwave signals; inner cavity multipaths contributions can thereby be suppressed by cleaning the spurious frequencies from the beating signal spectrum.
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WEPWA025	RF Acceleration of Ions Produced by Short Pulse Laser	laser, rfq, experiment, bunching	2548
	Y. Fuwa, M. Hashida, Y. Iwashita, S. Sakabe, H. Tongu Kyoto ICR, Uji, Kyoto, Japan M. Okamura BNL, Upton, Long Island, New York, USA A. Yamazaki Nagoya University, Nagoya, Japan
	Funding: This work was supported by Grant-in-Aid for Exploratory Research Number 23654085. RF acceleration of ions produced by short pulse laser is investigated. An RF cavity is prepared for the acceleration. Some experimental results will be presented.
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WEPWA027	Gas Flow Influence on Negative Hydrogen Ion Generation within the Microwave-Driven Negative Ion Source	ion-source, electron, operation, experiment	2555
	S.X. Peng, J.E. Chen, Z.Y. Guo, H.T. Ren, Y. Xu, A.L. Zhang, J.F. Zhang, T. Zhang, J. Zhao PKU, Beijing, People's Republic of China J. Zhao State Key Laboratory of Nuclear Physics and Technology, Beijing, Haidian District, People's Republic of China
	H⁻ ion was generated through two processes within a volume Cs- free source. The density of molecule hydrogen gas will impact the electron temperature within the primary discharge chamber that will influence the population of vibrationally excited H2*. Within the extraction region, the interaction between molecule hydrogen and H⁻ ion will is cause the dissociation of negative ion. To better understand the gas flow influence on H⁻ ion generation within a volume negative ion source, a new Cs-free volume microwave-driven H⁻ source body with two gas inlets was developed at Peking University (PKU). Experiment on gas flow and gas pressure distribution within the plasma chamber was carried out with this source body. In the meantime a two dimensional (2D) model for gas flow was developed. Details will be presented in this paper. [1] S.X. Peng, H.T. Ren, Y. Xu, T. Zhang, etc., CW/Pulsed H⁻ Ion Beam Generation with PKU Cs-free 2.45 GHz Microwave Driven Ion Source. O5-06, NIBS 2014, Accepted for publication in AIP, 2014/11/04.
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WEPWA031	A Compact Multiply Charged Ion Source for Hadrontherapy Facility	plasma, injection, ion-source, solenoid	2563
	L. Celona, L. Andò, G. Castro, F. Chines, G. Ciavola, S. Gammino, O. Leonardi, D. Mascali, L. Neri, D. Nicolosi, F. Noto, F. Romano, G. Torrisi INFN/LNS, Catania, Italy G. Ciavola CNAO Foundation, Milan, Italy G. Torrisi Universitá Mediterranea di Reggio Calabria, Reggio Calabria, Italy
	The ion sources, required by medical applications, must provide intense ion beams, with high reproducibility, stability and brightness. AISHa (Advanced Ion Source for Hadrontherapy) is a compact ECRIS whose hybrid magnetic system consists of a permanent Halbach-type hexapole magnet and a set of independently energized superconducting coils. These will be enclosed in a compact cryostat with two cryocoolers to operate without LHe. The microwave injection system has been designed for maximizing the beam quality through a fine frequency tuning within the 17.3-18.4 GHz band which is possible by using an innovative variable frequency klystron. The introduction of an integrated oven will allow the production of metal ions beams with relatively high intensity. “Accel-decel” extraction system will be used. The LEBT line will consist of a solenoid and a 90° dipole for ions selection. Two diagnostic boxes, made of Faraday cups, beam wires and slits, will allow the investigation of the beam composition and its properties. Moreover, a system of scintillating screens and CCD cameras, placed after the solenoid will allow the investigation of the Frequency Tuning Effect on the source performances.
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WEPWA041	Plans for a Linear Paul Trap at Rutherford Appleton Laboratory	multipole, quadrupole, plasma, resonance	2590
	D.J. Kelliher, S. Machida, D.C. Plostinar, C.R. Prior, S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	For over a decade, Linear Paul Traps (LPT) have been used in the study of accelerator beam dynamics. LPT studies exploit the similarity of the Hamiltonian with that of a beam in a quadrupole channel while having advantages in the flexibility of parameter choice, compactness and low cost. In collaboration with Hiroshima University, LPT research planned at STFC Rutherford Appleton Laboratory in the UK aims to investigate a range of topics including resonance crossing, halo formation, long-term stability studies and space-charge effects. Initially, a conventional quadrupole-based LPT will be built at RAL and used for a variety of experiments. In parallel, a design for a more advanced LPT that incorporates higher order multipoles will be pursued and later constructed. This multipole trap will allow non-linear lattice elements to be simulated and so broaden considerably the range of experiments that can be conducted. These will include the investigation of resonance crossing in non-linear lattices, a more detailed study of halo formation and the effect of detuning with amplitude. In this paper we report on progress made in the project to date and future plans.
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WEPWA059	RF Plasma-Based Ion Source Modeling on Unstructured Meshes	simulation, ion-source, plasma, electron	2637
	S.A. Veitzer, K.R.C. Beckwith, M. Kundrapu Tech-X, Boulder, Colorado, USA
	Funding: This work was performed under the auspices of the Department of Energy, Office of Basic Energy Sciences Award #DE-SC0009585. Ion source performance for accelerators and industrial applications can be improved through detailed numerical modeling and simulation. There are a number of technical complexities with developing robust models, including a natural separation of important time scales (rf, electron and ion motion), inclusion of plasma chemistry, and surface effects such as secondary electron emission and sputtering. Due to these computational requirements, it is typically difficult to simulate ion sources with Particle-In-Cell codes. An alternative is to use fluid-based codes coupled with electromagnetics in order to model ion sources. These types of models can simulate plasma evolution and rf-driven flows while maintaining good performance. We show here recent results on modeling the H⁻ ion source for the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) using the fluid plasma modeling code USim. We present new meshing capabilities for generating and parallelizing unstructured computational meshes that have increased our parallel code performance and enabled us to model inductively coupled plasmas for long periods of operation.
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WEPWA063	Beam-Plasma Effects in Muon Ionization Cooling Lattices	plasma, simulation, electron, space-charge	2649
	J.S. Ellison, P. Snopok IIT, Chicago, Illinois, USA
	Funding: Work is supported by the U.S. Department of Energy. New computational tools are essential for accurate modeling and simulation of the next generation of muon based accelerator experiments. One of the crucial physics processes specific to muon accelerators that has not yet been implemented in any current simulation code is beam induced plasma effect in liquid, solid, and gaseous absorbers. We report here on the progress of developing the required simulation tools and applying them to study the properties of plasma and its effects on the beam in muon ionization cooling channels.
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WEPJE001	Optimal Positron-Beam Excited Plasma Wakefields in Hollow and Ion-Wake Channels	plasma, electron, positron, wakefield	2674
	A. A. Sahai, T.C. Katsouleas Duke ECE, Durham, North Carolina, USA
	Funding: DE-SC-0010012, NSF-PHY-0936278 A positron-beam interacting with the plasma electrons drives radial suck-in, in contrast to an electron-beam driven blow-out in the over-dense regime, n_b>n₀. In a homogeneous plasma, the electrons are radially sucked-in from all the different radii. The electrons collapsing from different radii do not simultaneously compress on-axis driving weak fields. A hollow-channel allows electrons from its channel-radius to collapse simultaneously exciting coherent fields . We analyze the optimal channel radius. Additionally, the low ion density in the hollow allows a larger region with focusing phase. We have shown the formation of an ion-wake channel behind a blow-out electron bubble-wake. Here we explore positron acceleration in the over-dense regime comparing an optimal hollow-plasma channel to the ion-wake channel . The condition for optimal hollow-channel radius is also compared. We also address the effects of a non-ideal ion-wake channel on positron-beam excited fields. S Lee, T Katsouleas, Phys. Rev. E, vol 64, 045501(R) (2001) ** A A Sahai, T Katsouleas, Non-linear ion-wake excitation by ultra relativistic electron wakefields, in review (http://arxiv.org/pdf/1504.03735v1.pdf)
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WEPJE011	High Reliability, Long Lifetime, Continuous Wave H⁻ Ion Source	ion-source, electron, plasma, extraction	2695
	P. Barrows, G.E. Becerra PNL, Madison, Wisconsin, USA
	Funding: Small Business Innovation Research (SBIR) Phase II Phoenix Nuclear Labs (PNL) is developing a high-current, long-lifetime negative hydrogen (H⁻) ion source in partnership with Fermilab as part of an ion beam injector for future Intensity Frontier particle accelerators. In this application, continuous output with long lifetime and high reliability and efficiency are critical. Existing ion sources at Fermilab rely on plasma-facing electrodes and are limited to lifetimes of a few hundred hours, while requiring relatively high gas loads on downstream components. PNL's H⁻ ion source uses an electrodeless microwave plasma generator which has been extensively developed in PNL's positive ion source systems, demonstrating 1000+ hours of operation and >99% continuous uptime. A magnetic filter preferentially blocks energetic electrons produced in the plasma, while allowing cold electrons and fast neutrals through toward a cesiated surface converter to produce the desired H⁻ ions, which are extracted into a low energy beam using electrostatic lenses. The design specifications are 5-10 mA of continuous H⁻ current at 30 keV with <0.2 pi-mm-mrad beam emittance. Construction and testing of the H⁻ ion source is underway at PNL.
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WEPMA018	Status of the Ring RF Systems for FAIR	cavity, operation, antiproton, PLC	2789
	M. Frey, R. Balß, C. Christoph, O. Disser, G. Fleischmann, U. Hartel, P. Hülsmann, S. Jatta, A. Klaus, H. Klingbeil, H.G. König, U. Laier, D.E.M. Lens, D. Mondry, K.-P. Ningel, H. Richter, S. Schäfer, C. Thielmann, T. Winnefeld, B. Zipfel GSI, Darmstadt, Germany K. Groß, H. Klingbeil TEMF, TU Darmstadt, Darmstadt, Germany
	For the FAIR (Facility for Antiproton and Ion Research) synchrotron SIS100 and the storage ring CR (Collector Ring), different RF cavity systems are currently being realized. In addition to the standard RF bucket generation and acceleration, these ring RF systems also allow more complex beam manipulations such as barrier bucket operation or bunch rotation in phase space. Depending on their purpose, the cavities are either loaded with ferrite material or with MA (Magnetic Alloy) ring cores. Independent of the type of cavity, a complete cavity system consists of the cavity itself, a tetrode-based power amplifier, a solid-state pre-amplifier, a supply unit including PLC (Programmable Logic Control), and an RF control system (so-called LLRF, low level RF system). In this contribution, the different systems are described, and their current status is presented.
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WEPMA023	Advanced Multipoles and Appropriated Measurement Tools for Field Characterization of SIS100 Magnets	multipole, dipole, vacuum, superconducting-magnet	2805
	P. Schnizer, E.S. Fischer, A. Gottsmann, F. Kaether, A. Mierau, H.G. Weiss GSI, Darmstadt, Germany B. Schnizer TUG/ITP, Graz, Austria
	The heavy ion synchrotron SIS100 utilises fast ramped superconducting magnets. Describing and measuring these magnets requires advanced multipoles next to well adapted measurement techniques. We cover briefly the required theory adapted to the measurements, show which designs were available and which decisions had to be taken for measuring curved superconducting magnets. The series of SIS100 dipole magnets is going to be produced. These magnets will be measured at GSI. We present the foreseen field measurement procedure, outline the currently ongoing tests and give our calibration strategy.
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WEPMA024	System Design for a Deterministic Bunch-to-Bucket Transfer	synchrotron, simulation, LLRF, timing	2809
	T. Ferrand TEMF, TU Darmstadt, Darmstadt, Germany J.N. Bai IAP, Frankfurt am Main, Germany
	Funding: Supported by GSI and the Technical University Darmstadt in the frame of the cooperation for FAIR. A deterministic bunch to bucket transfer system is currently under development in the frame of the FAIR project at GSI. To achieve our accuracy and stability requirements, a set of hardware modules will be implemented. These hardware modules are expected to provide values such as the relative phase advance between the RF systems of both, the source and the target synchrotron according to an external timing system. These values are exchanged via optical fibers between different supply rooms, and the considered RF signals are re-synthesized locally. These re-synthesized signals are synchronized to enable a precise phase advance control between the synchrotrons’ RF systems. The first step of the development consists in modeling the actual DDS and DSP-based LLRF environment of the SIS18 under Ptolemy-II. Measurements on real devices will be performed concurrently to the simulation. We expect to use this simulation to refine our timing expectations regarding the synchronization process and the inter-module communication protocols and design the synchronization function, which will be implemented on the hardware modules.
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WEPMA034	Bakeout Concept for the HESR at FAIR	dipole, vacuum, heavy-ion, controls	2832
	H. Jagdfeld, N. Bongers, P. Chaumet, F.M. Esser, F. Jordan, F. Klehr, G. Langenberg, U. Pabst, L. Semke FZJ, Jülich, Germany
	Forschungszentrum Jülich has taken the leadership of a consortium being responsible for the design of the High-Energy Storage Ring (HESR) going to be part of the FAIR project at GSI. The HESR is designed for antiprotons but can be used for heavy ion experiments as well. Therefore the vacuum is expected to be 10^-11 mbar or better. To achieve this also in the curved sections where 44 bent dipole magnets with a length of around 4.5 m will be installed, NEG coated dipole chambers will be used to reach the needed pumping speed and capacity. For activation of the NEG-material a bakeout system must be installed. The bakeout concept including the layout of the control system and the systematization of the heater packages for all components of the vacuum system are presented. Also the special design of the heater jackets inside the dipole will be shown where the geometrical parameters are very critical and space is very limited. The results of the simulation of temperature distribution in the dipole iron are compared to temperature measurements carried out at a testbench with different layouts of the heater jackets. The final design of the dipole heater jackets will be illustrated.
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WEPMA057	Development of HTS magnets	dipole, neutron, cyclotron, target	2905
	K. Hatanaka, M. Fukuda, K. Kamakura, T. Saito, H. Ueda, Y. Yasuda, T. Yorita RCNP, Osaka, Japan
	We have been developing magnets utilizing high-temperature superconducting (HTS) wires for this decade. We built three model magnets, a mirror coil for an ECR ion source, a set of coils for a scanning magnet and a super-ferric dipole magnet to generate magnetic field of 3 T. They were excited with AC/pulse currents as well as DC currents. Recently we fabricated a cylindrical magnet for a practical use which polarizes ultracold neutrons (UCN). It consists of 10 double pancakes and the field strength at the center is higher than 3.5 T which is required to fully polarize 210 neV neutrons. It was successfully cooled and excited. The magnet was used to polarized UCN generated by the RCNP-KEK superthermal UCN source, One dipole magnet has been manufactured which is used as a switching magnet after the RCNP ring cyclotron and is excited by pulse currents. It becomes possible to deliver beams to two experimental halls by time sharing. Their designs and performances are presented in the talk.
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WEPMN021	Design and Research of Secondary Electron Emission Test Equipment with Low Electron Energy	electron, gun, vacuum, accumulation	2970
	Y.H. Xu, L. Fan, Y.Z. Hong, X.T. Pei, J. Wang, Y. Wang, W. Wei, B. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China
	In particle accelerators, the secondary electrons resulting from the interaction between particles and vacuum chamber have a great impact on beam quality. Especially for positron, proton and heavy ion accelerators, massive electrons lead to electron cloud, which affects the stability, energy, emittance and beam life adversely. We have studied the secondary electron emission (SEE) of metal used for accelerators. A secondary electron emission measurement system with low electron energy has been designed and used to measure the SEE yield of metal and non-evaporable getter materials. With the equipment, we have obtained the characteristic of the SEE yield of stainless steel and oxygen free copper (OFC).
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WEPMN024	Exploration of Multi-fold Symmetry Element-loaded Superconducting Radio Frequency Structure for Reliable Acceleration of Low- & Medium-Beta Ion Species	cavity, acceleration, SRF, RF-structure	2978
	S.C. Huang IMP/CAS, Lanzhou, People's Republic of China R.L. Geng JLab, Newport News, Virginia, USA
	Reliable acceleration of low- to medium-beta proton or heavy ion species is needed for future high current superconducting radio frequency accelerators. Due to the high-Q nature of a superconducting RF resonator, it is sensitive to many factors such as loading variation (from either the accelerated beam or from parasitic field emitted electrons), mechanical vibration, and liquid helium bath pressure fluctuation etc. To increase the stability against those factors, a mechanically strong and stable RF structure is desirable. Guided by this consideration, multi-fold symmetry element-loaded superconducting radio frequency structures, cylindrical tanks with multiple (n>=3) rod-shaped radial elements, are being explored. The top goal of its optimization is to improve mechanical stability. A natural consequence of this structure is a lowered ratio of the peak surface electromagnetic field to the acceleration gradient as compared to the traditional spoke cavity. A disadvantage of this new structure is an increased size for a fixed resonant frequency and optimal beta. This paper describes the optimization of EM design and preliminary mechanical analysis for such structures.
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WEPMN025	Harmonic Resonant Kicker Design for the MEIC Electron Circular Cooler Ring	cavity, electron, impedance, kicker	2981
	Y.L. Huang IMP/CAS, Lanzhou, People's Republic of China R.A. Rimmer, H. Wang, S. Wang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S.DOE Contract No. DE-AC05-06OR23177. Bunched-beam electron cooling of the high-energy ion beam emittance may be a crucial technology for the proposed Medium energy Electron Ion Collider (MEIC) to achieve its design luminosity. A critical component is a fast kicker system in the Circular Ring (CR) that periodically switches electron bunches in and out of the ring from and to the driver Energy Recovery Linac (ERL). Compared to a conventional strip-line type kicker, a quarter wave resonator (QWR) based deflecting structure has a much higher shunt impedance and so requires much less RF power. The cavity has been designed to resonate simultaneously at many harmonic modes that are integer multiples of the fundamental mode. In this way the resulting waveform will kick only a subset of the circulating bunches. In this paper, analytical shunt impedance optimization, the electromagnetic simulations of this type of cavity, as well as tuner and coupler concept designs to produce 5 odd and 5 even harmonics of 47.63MHz will be presented, in order to kick every 10th bunch in a 476.3 MHz bunch train.
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WEPMN052	A New RF Laboratory for Developing Accelerator Cavities at the University of Huelva	cavity, heavy-ion, rfq, network	3046
	I. Martel, C. Bonțoiu, J.A. Dueñas, D. Gordo-Yáñez, A.K. Orduz, J. Sanchez-Segovia University of Huelva, Huelva, Spain
	The University of Huelva is presently involved in R&D projects for developing RF accelerator cavities. Two types of cavities are presently under design, a prototype of room temperature RFQ injector and a quarter-wave resonator for high intensity heavy-ion linear accelerators. The laboratory is equipped with dedicated test-bench for RF measurements, which includes high-power RF generators, network analyzer, amplifiers and power meters. A clean room is also available having a dedicated space for high-precision mechanical metrology and cavity mounting, together with a vertical cryostat for superconducting cavity test.
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WEPMN057	Calculation and Design of a RF Cavity for a Novel Compact Superconducting Cyclotron for Radioisotope Production	cavity, cyclotron, focusing, simulation	3055
	D. Gavela, J. Calero, L. García-Tabarés, A. Guirao, D. Obradors-Campos, C. Oliver, J.M. Pérez Morales, I. Podadera, F. Toral CIEMAT, Madrid, Spain
	Funding: Work partially funded by CDTI and the Spanish Ministry of Economy and Competitiveness, under the subprogram CENIT, project AMIT, reference CEN-20101014 The AMIT cyclotron will be a 8.5 MeV, 10 microAmp, CW, H⁻ accelerator for the purpose of radioisotope production. It includes a superconducting, weak focusing, 4 T magnet, which allows for a low extraction radius and a compact design. The RF cavity design has to deal with challenging requirements: high electric fields created by the required accelerating voltage (60 kV – 70 kV) on a small gap, a small aperture of the magnet leading to high capacitances and thermal losses, and a requirement for a low overall size of the cavity. A quarter wave resonator with one dee (two acceleration gaps) design was chosen. Calculations with HFSS have been performed to compute the resonant frequency, tuners sensitivity, S-parameters, power losses and geometry for input coupler and pickup. A structural Ansys model has been used to analyze the stresses and the deformations of the cavity. A thermal Ansys model was used for the design of the cooling circuits and the calculation of the temperature distribution. Finally, the fluid dynamics of the cooling circuits have been carefully studied. The results of these calculations and the consequent design decisions are presented in this paper.
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WEPHA009	Propagation of Radioactive Contaminants Along the Isolde Beamline	vacuum, target, simulation, proton	3115
	R. Kersevan, M. Ady, A. Dorsival, A. Gottberg, M. Maietta, G. Vandoni CERN, Geneva, Switzerland
	The vacuum system of RIB facilities is entirely hermetical, with storage of effluents and controlled release to atmosphere after a decay time. In Isolde, distributed primary pumping is sectorized in three parts, but all effluents are conveyed together in a unique tank. Thus, highly contaminated gas from the target and front end may be mixed with less contaminated gas from the beam transfer lines. This study aims at analysing and quantifying the distribution and propagation of neutral rare gas radioactive isotopes along the Isolde beam-line by numerical simulation (steady-state and time resolved Test-Particle Monte-Carlo, Molflow+) and experimental means. The time-resolved Monte-Carlo integrates decay time for the propagating species. To measure the distribution of contaminants, sampling filters are installed at the exhaust of the vacuum turbo-molecular pumps. Comparison between simulation and experiment shows excellent agreement, confirming the pertinence of the Monte-Carlo tool to radioactive species propagation. The filtering effect of magnetic sectors, the RFQ Cooler, and Buncher on the propagating neutral isotopes are quantified.
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WEPHA010	The Vacuum System of the Extra-Low Energy Antiproton Decelerator ELENA at CERN	vacuum, antiproton, dipole, electron	3119
	R. Kersevan CERN, Geneva, Switzerland
	The Extra-Low ENergy Antiproton decelerator (ELENA) project is under way since 2011. In the past 3 years, it has considerably evolved into a detailed design for the ring and the transfer lines. It is a small machine, ~30 m in circumference, with a rather tight specification for the average pressure seen by the anti-proton beams injected by the anti-proton decelerator (AD). The average pressure in ELENA must be limited to 4x10^-12 mbar (H2-equivalent) in order to limit the charge-exchange losses during the rather long deceleration process (several tens of seconds), during which the energy of the beam is reduced and the electron-cooler is used twice in order to decrease the transverse emittance of the anti-proton beam. This paper will discuss the design of the chambers of the injection line, extraction line and the ring. It will also mention the actual status of the vacuum system for the transfer lines to the experiments, LNE, which are under finalisation. The results of detailed 3D simulations made with the test-particle montecarlo code Molflow+ will be discussed, alongside with the choice for the pumping system, mainly distributed NEG-coatings and integrated NEG/ion-pumps.
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WEPHA022	Characterization of Nb Coating in HIE-ISOLDE QWR Superconducting Accelerating Cavities by means of SEM-FIB and TEM	cavity, interface, electron, niobium	3155
	B. Bártová, S. Calatroni, A. Sublet, M. Taborelli CERN, Geneva, Switzerland A.B. Aebersold, D.T.L. Alexander, M. Cantoni EPFL, Lausanne, Switzerland
	The Quarter Wave Resonators (QWR) high-β cavities (0.3m diameter and 0.9m height) are made from OFE 3D-forged copper and are coated by DC-bias diode sputtering with a thin superconducting layer of niobium. The Nb film thickness, morphology, purity and quality are critical parameters for RF performances of the cavity. They have been investigated in a detailed material study. The coating structure at different positions along a test cavity was observed by cross-section imaging using SEM-FIB instrument. The samples from the top of the cavity showed presence of unexpected porosities, whose volume was investigated using FIB tomography. TEM lamella was prepared for two samples (top part and inner conductor of the cavity) to study in detail the grain orientation in the coating, its chemical composition and structure. The 14-layer structure in thick coating was indeed evidenced by the TEM analysis. Chemical mapping revealed the presence of a few nm in size copper precipitates close to the Nb/Cu interface and a passivating oxide layer of 10 nm thickness on top of the coating and around porosities. However no impurities or interface layer along the coating profile were present.
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WEPHA046	Outgassing Analysis During Transport for 14m Long Arc-Cell Vacuum Chambers of the Taiwan Photon Source	vacuum, photon, storage-ring, electron	3219
	L.H. Wu, C.K. Chan, C.H. Chang, C.-C. Chang, S.W. Chang, Y.P. Chang, B.Y. Chen, J.-R. Chen, Z.W. Chen, C.M. Cheng, G.-Y. Hsiung, S-N. Hsu, H.P. Hsueh, C.S. Huang, Y.T. Huang, T.Y. Lee, I.C. Yang NSRRC, Hsinchu, Taiwan J.-R. Chen National Tsing Hua University, Hsinchu, Taiwan
	An outgassing analysis during transportation for the large, 14-m-long, ultra-high-vacuum aluminum arc-cell chambers of the Taiwan Photon Source (TPS) was performed using residual gas analysis (RGA). Each cell was baked to 150 °C in the laboratory to achieve ultra-high vacuum. Under pumping by primarily ion pumps (IP) and non-evaporable getter (NEG) pumps, the cells obtained pressures of 6.4×10^-9 Pa on average, and the main residual gas was H2. Here, vacuum pressure measurements and residual gas analyses were performed in situ while a cell chamber was being transported. It was found that the vibration of the arc-cell vacuum chamber caused the pressure to rise abruptly; in this case, the main outgassing gas was CH4. Once the arc cell had been fully installed, the vacuum pressure gradually decreased to the original vacuum pressure because of the pumping effect of the ion gauges.
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WEPTY028	Fermilab Linac Laser Notcher	laser, linac, booster, cavity	3328
	D.E. Johnson, K.L. Duel, M.H. Gardner, T.R. Johnson, V.E. Scarpine, R. Tesarek Fermilab, Batavia, Illinois, USA
	Synchrotrons or storage rings require a small section of their circumference devoid of any beam (i.e. a “notch”) to allow for the rise time of an extraction kicker device. In multi-turn injection schemes, this notch in the beam may be generated either in the linac pulse prior to injection or in the accelerator itself after injection. In the case of the Fermilab Booster, the notch is created in the ring near injection energy by the use of fast kickers, thus depositing the beam in a shielded collimation region within the accelerator tunnel. With increasing beam powers, it is desirable to create this notch at the lowest possible energy to minimize activation. Fermilab has undertaken an R&D project to build a laser system to create the notch within a linac beam pulse, immediately after the RFQ at 750 keV, where activation issues are negligible. We will describe the concept for the laser notcher and discuss our current status and future plans for installation of the device.
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WEPTY048	An RFQ Direct Injection Scheme for the IsoDAR High Intensity H²⁺ Cyclotron	rfq, cyclotron, injection, ion-source	3384
	D. Winklehner, J.R. Alonso, J.M. Conrad MIT, Cambridge, Massachusetts, USA R.W. Hamm R&M Technical Enterprises, Pleasanton, California, USA
	IsoDAR is a novel experiment designed to measure neutrino oscillations through electron-antineutrino disappearance, thus providing a definitive search for sterile neutrinos. In order to generate the necessary anti-neutrino flux, a high intensity primary proton beam is needed. In IsoDAR, H²⁺ is accelerated, and is stripped into protons just before the target, to overcome space charge issues at injection. As part of the design, we have refined an old proposal to use an RFQ to axially inject bunched H²⁺ ions into the driver cyclotron. This method has several advantages over a classical low energy beam transport (LEBT) design: (1) The bunching efficiency is higher than for the previously considered two-gap buncher and thus the overall injection efficiency is higher. This relaxes the constraints on the H²⁺ current required from the ion source. (2) The overall length of the LEBT can be reduced. (3) The RFQ can also accelerate the ions. This enables the ion source platform high voltage to be reduced from 70 kV to 30 kV, making underground installation easier. We will present preliminary RFQ design parameters and first beam dynamics simulations from the ion source to the spiral inflector.
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WEPTY061	Progress on the Cryogenic and Current Tests of the MSU Cyclotron Gas Stopper Superconducting Magnet	cyclotron, cryogenics, vacuum, dipole	3415
	M.A. Green, G. Bollen, S. Chouhan, A.F. Zeller FRIB, East Lansing, Michigan, USA J. DeKamp, C. Magsig, D.J. Morrissey, J. Ottarson, S. Schwarz NSCL, East Lansing, Michigan, USA
	Funding: This work reported in this paper was supported in part by an NSF grant PHY-0958726 The Michigan State University (MSU) cyclotron gas stopper magnet is a warm iron superconducting cyclotron dipole. The desired field shape is obtained by the pole iron profile. Each coil of the two halves is in a separate cryostat and connected in series through a warm electrical connection. The entire system is mounted on a high voltage platform, and is cooled using six two-stage 4.2 K pulse tube coolers. This paper presents the progress on the magnet fabrication, cooling, and current testing.
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WEPWI012	First Attempt of At-cavity X-ray Detection in a CEBAF Cryomodule for Field Emission Monitoring	cavity, cryomodule, cryogenics, electron	3515
	R.L. Geng, E. Daly, M.A. Drury, A.D. Palczewski JLab, Newport News, Virginia, USA
	We report on the first result of at-cavity X-ray detection in a CEBAF cryomodule for field emission monitoring. In the 8-cavity cryomodule F100, two silicon diodes were installed near the end flange of each cavity. Each cavity was individually tested during the cryomodule test in JLab’s cryomodule test facility. The behaviors of these at-cavity cryogenic X-ray detectors were compared with those of the standard “in air” Geiger-Muller tubes. Our initial experiments establish correlation between X-ray response of near diodes and the field emission source cavity in the 8-cavity string. For two out of these eight cavities, we also carried out at-cavity X-ray detection experiment during their vertical testing. The aim is to track field emission behavior uniquely from vertical cavity testing to horizontal cavity testing in the cryomodule.
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WEPWI022	RF System Requirements for a Medium-Energy Electron-Ion Collider (MEIC) at JLab	electron, collider, booster, SRF	3536
	R.A. Rimmer, J. Guo, J. Henry, H. Wang, S. Wang JLab, Newport News, Virginia, USA Y.L. Huang IMP/CAS, Lanzhou, People's Republic of China
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 JLab is studying options for a medium energy electron-ion collider that could fit on the JLab site and use CEBAF as a full-energy electron injector. A new ion source, linac and booster would be required, together with collider storage rings for the ions and electrons. In order to achieve the maximum luminosity these will be high current storage rings with many bunches. We present the high level RF system requirements for the storage rings, ion booster ring and high-energy ion beam cooling system, and describe the technology options under consideration to meet them. We also present options for staging that might reduce the initial capital cost while providing a smooth upgrade path to a higher final energy. The technologies under consideration may also be useful for other proposed storage ring colliders or ultimate light sources.
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WEPWI024	Vacuum Characterization and Improvement for the Jefferson Lab Polarized Electron Source	electron, vacuum, background, gun	3540
	M.L. Stutzman, P.A. Adderley, M. Poelker JLab, Newport News, Virginia, USA M.A. Mamun Old Dominion University, Norfolk, Virginia, USA
	Operating the JLab polarized electron source with high reliability and long lifetime requires vacuum near the XHV level (<=1x10^-12 Torr). This paper describes ongoing vacuum research at Jefferson Lab including characterization of outgassing rates for surface coatings and heat treatments, ultimate pressure measurements, investigation of pumping including an XHV cryopump, and characterization of ionization gauges in this pressure regime.
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WEPWI040	Experiment and Results on Plasma Etching of SRF Cavities	cavity, plasma, SRF, niobium	3581
	J. Upadhyay, J.J. Peshl, S. Popović, L. Vušković ODU, Norfolk, Virginia, USA D.S. Im Old Dominion University, Norfolk, Virginia, USA H.L. Phillips, A-M. Valente-Feliciano JLab, Newport News, Virginia, USA
	The inner surfaces of SRF cavities are currently chemically treated (etched or electro polished) to achieve the state of the art RF performance. We designed an apparatus and developed a method for plasma etching of the inner surface for SRF cavities. The process parameters (pressure, power, gas concentration, diameter and shape of the inner electrode, temperature and positive dc bias at inner electrode) are optimized for cylindrical geometry. The etch rate non-uniformity has been overcome by simultaneous translation of the gas point-of-entry and the inner electrode during the processing. A single cell SRF cavity has been centrifugally barrel polished, chemically etched and RF tested to establish a baseline performance. This cavity is plasma etched and RF tested afterwards. The effect of plasma etching on the RF performance of this cavity will be presented and discussed.
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THXC2	Ion Beam Therapy with Ions Heavier than Protons: Performance and Prospects	proton, neutron, radiation, shielding	3654
	U. Linz FZJ, Jülich, Germany

Paper

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MOPWA024

Estimation of the Ion Density in Accelerators using the Beam Transfer Function Technique

electron, betatron, synchrotron, impedance

147

D. Sauerland, W. Hillert
ELSA, Bonn, Germany
A. Meseck
HZB, Berlin, Germany

Funding: Funded by the federal ministry of education and science of Germany
The ELSA stretcher ring of Bonn University serves external hadron physics experiments with a quasi continuous electron beam of up to 3.2 GeV energy. Ions, being generated by collisions of the circulating electrons with the residual gas molecules, accumulate inside the beam potential, causing incoherent tune shifts and coherent beam instabilities. Detailed measurements were carried out in which ion dynamics is studied in dependence of beam energy and current, filling patterns and bias voltages of the ion clearing electrodes. By measuring the beam transfer function using a broadband transversal kicker, we were able to derive an estimate of the average ion density from the shift and broadening of the tune peak. In this contribution first results of these measurements are presented.

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MOPWA025

Simulation of Laser Cooling of Heavy Ion Beams at High Intensities

laser, synchrotron, scattering, simulation

150

L. Eidam, O. Boine-Frankenheim, D.F.A. Winters
GSI, Darmstadt, Germany

In the past the principle of Doppler laser cooling was investigated and verified in storage rings in the low energy regime. Within the FAIR project the laser cooling will be applied to high intensity and high energy beams for the first time. The laser cooling results in a further increase of the longitudinal phase space density and in non-Gaussian longitudinal beam profiles. In order to ensure stable operation and optimize the cooling process the interplay of the laser force and high intensity effects has to be studied numerically. This contribution will identify constrains of the cooling scheme for an efficient reduction of momentum spread. For high beam energies the scattering of photons has to be treated stochastically instead of using averaged forces. The modeling of the laser force in a particle in cell tracking code will be discussed.

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MOPWA026

Demonstration of Flat Ion Beam Creation and Injection into a Synchrotron

emittance, solenoid, injection, synchrotron

153

L. Groening, S. Appel, L.H.J. Bozyk, Y. El Hayek, M.T. Maier, C. Xiao
GSI, Darmstadt, Germany

At GSI an ion beam with different horizontal and vertical emittances has been created from a beam with initially equal emittances. This round-to-flat adoption has been accomplished without any beam loss. In the set-up the beam passes through a stripping foil placed inside a solenoid followed by a skewed quadrupole triplet. The amount of beam flatness has been controlled by setting the solenoid field strength only. Increase of the product of the two transverse emittances is purely due to the stripping process that occurs anyway along an ion linac. Beams with different amounts of flatness were injected into a synchrotron applying horizontal multi-turn injection. The efficiency of injection increased as smaller as the horizontal emittance was set by the round-to-flat adaptor.

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MOPWA028

Resonance Compensation for High Intensity Bunched Beams

resonance, space-charge, sextupole, controls

159

G. Franchetti, S. Aumon, F. Kesting, H. Liebermann, C. Omet, D. Ondreka, R. Singh
GSI, Darmstadt, Germany

Mitigation of periodic resonance crossing induced by space charge is foreseen via classic resonance compensation. The effect of the space charge is, however, not obvious on the effectiveness on the compensation scheme. In this proceeding we report on an experimental campaign performed at SIS18 in an attempt to investigate experimentally the effect of space charge on the resonance compensation. The experimental results and their consequences are discussed through numerical simulations.

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MOPWA036

Status of Injection Studies into the Figure-8 Storage Ring

injection, simulation, experiment, kicker

187

J.F. Wagner, A. Ates, M. Droba, O. Meusel, H. Niebuhr, D. Noll, U. Ratzinger
IAP, Frankfurt am Main, Germany

The ongoing investigations on the design of the Figure-8 Storage Ring* at Frankfurt University focus on the beam injection. The research includes simulations as well as a scaled down experiment. The studies for an optimized adiabatic magnetic injection channel, starting from a moderate magnetic field up to a maximum of 6 Tesla, with a realistic field model of toroidal coils due to beam dynamics with space charge will be shown. For the envisaged ExB kicker system the simulations deal with beam potential constraints and a multi-turn injection concept in combination with an adiabatic magnetic compression. To investigate the concept of the beam injection into a toroidal magnetic field, a scaled down room temperature experiment is implemented at the university. It is composed of two 30 degree toroidal segments, two volume ion sources, two solenoids and two different types of beam detectors. The experiment is used to investigate the beam transport and dynamics of the laterally injected and “circulating” beam through the magnetic configuration. To set up the injection experiment, theoretical calculations and beam simulations with bender** are used.
* M. Droba et al., Proc. of IPAC'14, Dresden, Germany, TUPRO045
** D. Noll, M. Droba, O. Meusel, U. Ratzinger, K. Schulte, C.Wiesner, Proc. of HB2014, East Lansing, USA, WEO4LR02

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MOPWA047

Start to End Simulation of High Current Injector using TRACEWIN Code

DTL, rfq, optics, linac

223

S. Kumar, A. Mandal
IUAC, New Delhi, India

High Current Injector (HCI) is an alternate injector to superconducting linac at IUAC in addition to pelletron. It consists mainly of high temperature superconducting ECR ion source (PKDELIS), radio frequency quadrupole (RFQ)* and a drift tube linac (DTL)**. The ions of mass to charge (A/q) ratio of 6 are analysed initially and accelerated through RFQ and DTL to a total energy of 1.8 MeV/u. The different energy regimes connecting the accelerating stages are named as low, medium and high energy beam transport section (LEBT, MEBT and HEBT). The energy spread of beam increases from 0.02% at ECR source to 0.5% at the DTL exit. An ion beam of normalized transverse and longitudinal emittance of 0.03 pi mm-mrad and 0.3 keV/u-ns has been considered at the start for the simulation of ion optics using TRACEWIN*** code. The whole beam transport system has been designed using GICOSY, TRANSPORT and TRACE 3D codes piecewise and TRACEWIN code is used to simulate whole ion optics from start to end including acceleration stages such as RFQ and DTL. Simulation results shows that beam can be injected through LEBT, MEBT and HEBT into LINAC without significant emittance growth and beam loss.
* Sugam Kumar et al., Proc. of InPAC-2011, IUAC, New Delhi
** B.P. Ajith Kumar et al., Proc. of InPAC-2009, RRCAT, Indore
*** http://irfu.cea.fr/Sacm/logiciels/index3.php

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MOPWA048

Transverse Emittance Measurement for Low Energy Ion Beams Using Quadrupole Scan Method

emittance, plasma, ion-source, ECR

226

S. Kumar, A. Mandal
IUAC, New Delhi, India

Low energy ion beam facility (LEIBF) * at IUAC consists of all permanent magnet 10 Ghz electron cyclotron resonance (ECR) ion source (NANOGUN) ** along with 400 kV high voltage accelerating platform, a switching cum analysing magnet and electrostatic quadrupoles. Higher beam currents of heavy charge states and low energy of ion beams puts tremendous challenge to transport the ion beam from source to target. The normalized emittance of analysed ion beam is measured for specific charge to mass ratio using electrostatic quadrupole scan method *** for various source parameters like RF power and injection pressure of gas etc. For various m/q ratios, the normalized transverse emittance ranges from 0.1 to 0.6 mm-mrad. It is attributed to beam rotation induced by ECR axial magnetic field, effect of ion temperature in plasma, non linear electric fields and space charge etc which play a significant role in emittance growth.
* A. Mandal et. al. Proceedings of IPAC2011, WEPC011, San Sebastián, Spain
** D Kanjilal et. al. Indian J. Pure Appl. Phys. 39 (2001) 25
*** I. G. Brown:The physics and technology of ion sources

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MOPWA052

Formation of a Uniform Ion Beam Based on Nonlinear Focusing and its Applications at the JAEA TIARA Cyclotron

cyclotron, scattering, target, octupole

236

Y. Yuri, I. Ishibori, T. Ishizaka, S. Okumura, K. Yoshida, T. Yuyama
JAEA/TARRI, Gunma-ken, Japan

A formation/irradiation technique of large-area uniform beams based on nonlinear focusing of multipole magnets has been developed toward advanced research and efficient industrial applications at the TIARA AVF cyclotron of Japan Atomic Energy Agency. The uniform beam is formed as follows: An ion beam extracted from the cyclotron is multiply-scattered with a thin foil so that the transverse beam intensity distribution can be smoothed into a Gaussian-like distribution, critical to the formation of a highly uniform distribution. Then, the tail of the Gaussian-like distribution is folded into the inside by the nonlinear force of octupole magnets and eventually a uniform intensity distribution can be formed on a target. Typically, the area and uniformity of the beam are over 100 cm² and below 10%, respectively. Such large-area uniform beams have already been applied to radiation degradation testing of space-use solar cells and a study on functional materials in TIARA. In the presentation, the latest R&D results and the utilization status of the uniform beam will be shown.

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MOPJE016

Start-to-End Simulation for RAON Superconducting Linac

linac, cryomodule, lattice, emittance

311

H. Jang, J.-H. Jang, H. Jin
IBS, Daejeon, Republic of Korea

An ion accelerator, RAON is going to be built in Daejeon, Korea by Rare Isotope Science Project(RISP) team in Institute of Basic Science(IBS). The linac part of RAON consists of two low energy linacs, one high energy linac and two bending section for transporting accelerated low energy ions to high energy linac. It is planned to accelerate many diverse ions like proton, carbon, calcium, uranium, etc. which have different A/q values. Consequently the lattice design for each ion and to investigate beam dynamics issues for each case are one of the important topics for this project. For enhancement of beam acceleration a study to suppress emittance growth and to maximize the longitudinal acceptance is conducted while designing the RAON lattice. In this presentation the designed linac lattices for various ions and start-to-end simulation results will be described.

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MOPJE017

Error Analysis and Correction at the Main LEBT of RAON Heavy Ion Accelerator

GUI, rfq, heavy-ion, simulation

314

H. Jin, I.S. Hong, H. Jang, J.-H. Jang
IBS, Daejeon, Republic of Korea

The main Low Energy Beam Transport (LEBT) section of Rare isotope Accelerator Of Newness (RAON) heavy ion accelerator is designed to transport the ion beams which are generated by Electron Cyclotron Resonance Ion Source (ECR-IS) to the Radio Frequency Quadrupole (RFQ). In the main LEBT, one or two beams are selected among a variety of ion beams to meet the beamline experiment requirements such as beam charge and current. In a uranium beam case, two charge-state, 33+ and 34+, beams are chosen and transported to the RFQ. For transportation of two charge-state beams, beams can be seriously affected by dipole kick or unexpected dispersion caused by magnet errors. These effects of magnet or cavity errors lead to beam loss at the main LEBT or RFQ. Therefore, the effect to the beam orbit and size should be identified and the research for reducing such effect should be required in the main LEBT. In this paper, we will examine the orbit distortion and beam size growth caused by magnet errors and discuss the correction of errors by using correctors and BPMs.

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MOPJE022

Physical Model of Partial RF Discharge in Isochronous Cyclotrons

electron, cyclotron, plasma, ion-source

323

V.S. Dyubkov
MEPhI, Moscow, Russia
S. Korenev
Siemens Medical Solutions Molecular Imaging, Knoxville, TN, USA

The physical model for the partial RF discharge - based on the ionization of molecules of residual gas by electron detachment as a result of the electro-dissociation of negative hydrogen ions in isochronous cyclotrons - is proposed in this paper. The result of the simulation of the ionization of gas molecules by these electrons using RF voltage inside the Eclipse cyclotron (kinetic energy of 11 MeV) is presented. The analysis of the conductivity of the RF plasma (partial RF discharge) is given. The influence of the magnetic field on the properties of the partial RF discharge is discussed. The application of this model is for isochronous cyclotrons with low kinetic energy (10^-15 MeV).

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MOPMA005

Non-invasive Beam Profile Monitoring

detector, vacuum, operation, proton

537

C.P. Welsch, T. Cybulski, A. Jeff, V. Tzoganis, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
T. Cybulski, A. Jeff, V. Tzoganis, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
A. Jeff
CERN, Geneva, Switzerland
V. Tzoganis
RIKEN, Saitama, Japan

Funding: Work supported by the Helmholtz Association under contract VH-NG-328, the EU under contracts 215080 and 289485, as well as the STFC Cockcroft core grant No. ST/G008248/1.
State-of-the-art high energy and high intensity accelerators require new approaches to transverse beam profile monitoring as many established techniques will no longer work due to the high power stored in the beam. In addition, many accelerator applications such as ion beam cancer therapy or material irradiation would benefit significantly from the availability of non-invasive beam profile monitors. Research in the QUASAR Group has focused on this area over the past 5 years. Two different approaches were successfully developed: Firstly, a supersonic gas jet-based monitor was designed and commissioned. It enables the detection of the 2-dimensional transverse beam profile of essentially any charged particle beam with negligible disturbance of the primary beam and accelerator vacuum. Secondly, a monitor based on the Silicon strip VELO detector, originally developed for the LHCb experiment, was tested as an online beam monitor at the Clatterbridge Cancer Center in the UK. The design of both monitors is presented in this contribution. Results from measurements are discussed and complemented by numerical studies into the performance limits of either technique.

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MOPMN007

An Alternate Ring-Ring Design for eRHIC

electron, collider, proton, linac

713

Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and No. DE-AC02-06CH11357
I present here a new ring-ring design of eRHIC. It utilizes high repetition rate colliding beams and is likely able to deliver the performance to meet the requirements of the science program with low technical risk and modest accelerator R&D. The expected performance includes high luminosities over multiple collision points and a broad CM energy range with a maximum value up to 2×1034 cm^-2s⁻¹ per detector, and polarization higher than 70% for the colliding electron and light ion beams. This new design calls for reuse of decommissioned facilities in the US, namely, the PEP-II high energy ring and one section of the SLAC linac as a full energy injector.

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MOPMN012

SPACE Code for Beam-Plasma Interaction

plasma, simulation, electron, electromagnetic-fields

728

K. Yu, V. Samulyak
SBU, Stony Brook, USA
V. Samulyak
BNL, Upton, Long Island, New York, USA

A parallel particle-in-cell code SPACE has been developed for the simulation of electromagnetic fields, relativistic particle beams, and plasmas. The algorithms include atomic processes in the plasma, proper boundary conditions, an efficient method for highly-relativistic beams in non-relativistic plasma, support for simulations in relativistic moving frames, and special data transfer algorithm from the moving to the laboratory frame that collects particles and fields in the lab frame without time shift due to the Lorentz transform, enabling data analysis and visualization. Plasma chemistry algorithms implement atomic physics processes such as the generation and evolution of plasma, recombination of plasma, and electron attachment on dopants in dense neutral gas. Benchmarks and experimental validation tests are also discussed. The code has been used for the simulation of processes relevant to the eRHIC program at BNL and the high pressure RF cavity (HPRF) program at Fermilab.

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MOPMN013

Simulation of Beam-Induced Plasma in Gas Filled Cavities

plasma, simulation, cavity, electron

731

K. Yu, V. Samulyak
SBU, Stony Brook, USA
M. Chung
UNIST, Ulsan, Republic of Korea
B.T. Freemire
IIT, Chicago, Illinois, USA
V. Samulyak
BNL, Upton, Long Island, New York, USA
A.V. Tollestrup, K. Yonehara
Fermilab, Batavia, Illinois, USA

Understanding of the interaction of muon beams with plasma in muon cooling devices is important for the optimization of the muon cooling process. SPACE, a 3D electromagnetic particle-in-cell (EM-PIC) code, is used for the simulation support of the experimental program on the hydrogen gas filled RF cavity in the Mucool Test Area (MTA) at Fermilab. We have investigated the plasma dynamics in the RF cavity including the process of power dump by plasma (plasma loading), recombination of plasma, and plasma interaction with dopant material. By comparison with experiments in the MTA, simulations suggest several unknown properties of plasma such as the effective recombination rate, the electron attachment time on dopant molecule, and the ion - ion recombination rate in the plasma.

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MOPMN030

Proton Spin Tracking with Symplectic Integration of Orbit Motion

proton, closed-orbit, resonance, sextupole

766

Y. Luo, Y. Dutheil, H. Huang, F. Méot, V.H. Ranjbar
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Symplectic integration for orbital motion had been adopted in SimTrack which has been extensively used for dynamic aperture calculation with beam-beam interaction for the Relativistic Heavy Ion Collider (RHIC). Recently spin tracking for protons has been implemented on top of the orbit motion in this code. In this article, we will explain the implementation of spin motion using Thomas-BMT equation, and benchmark with other spin tracking codes currently used for RHIC. Possibility and remedy for very-long term particle tracking, such as on the RHIC energy acceleration, is also explored.

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MOPHA013

Superconducting Radio Frequency Cavity Degradation Due to Errant Beam

cavity, ion-source, linac, vacuum

805

C.C. Peters, D. Curry, G.D. Johns
ORNL RAD, Oak Ridge, Tennessee, USA
A.V. Aleksandrov, W. Blokland, M.T. Crofford, C. Deibele, G.W. Dodson, J. Galambos, T.A. Justice, S.-H. Kim, T.A. Pelaia II, M.A. Plum, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05- 00OR22725 for the U.S. Department of Energy.
In 2009, the Superconducting Radio Frequency (SRF) cavities at the Spallation Neutron Source (SNS) began to experience significant operational degradation [1]. The source of the degradation was found to be repeated striking of cavity surfaces with errant beam pulses. The Machine Protection System (MPS) was designed to turn the beam off during a fault condition in less than 20 μseconds [2] as these errant beam pulses were not unexpected. Unfortunately an improperly operating MPS was not turning off the beam within the designed 20 μseconds, and the SRF cavities were being damaged. The MPS issues were corrected, and the SRF performance was restored with cavity thermal cycling and RF processing. However, the SRF cavity performance has continued to degrade, though at a reduced rate compared to 2009. This paper will detail further study of errant beam frequency, amount lost per event, causes, and the corrective actions imposed since the initial event.

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MOPHA025

Control System for FRANZ Facility

controls, ion-source, proton, neutron

830

S.M. Alzubaidi, O. Meusel, U. Ratzinger, C. Wagner
IAP, Frankfurt am Main, Germany

The Frankfurt Neutron Source at the Stern- Gerlach Zentrum (FRANZ) will use the reaction of 7Li(p, n)7Be to produce an intense neutron beam. The neutron energy will be between 10 and 500 keV depending on the primary proton beam, which is variable between 1.8 and 2.2 MeV. A volume type ion source will be used to deliver a 120 keV proton beam with currents up to 200 mA. Like any other facility, FRANZ will need a powerful and reliable control system that also allows monitoring the whole accelerator target areas and experiments. Also interlock and safety systems have to be included to protect personnel from radiation hazards associated with accelerator operations and accompanying experiments. The FRANZ control system is still under development. The ion source will be the first element to be controlled, and to gain experience. A test ion source will be used for testing and examining the performance of this control system. In this paper, the plasma properties, filament ageing and an internal control loop for stable beam production with respect to controlling issues will be discussed.

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MOPHA050

Online Spill Intensity Monitoring for Improving Extraction Quality at CNAO

electron, proton, electronics, extraction

907

M. Caldara
University of Bergamo, Bergamo, Italy
J. Bosser, G.M.A. Calvi, L. Lanzavecchia, A. Parravicini, C. Viviani
CNAO Foundation, Milan, Italy
E. Rojatti
UniPV, Pavia, Italy

The CNAO Foundation is the first Italian center for deep hadrontherapy with Protons and Carbon Ions, performing treatments since September 2011. The extracted beam energy and intensity can vary over a wide range (60-250 MeV for Protons and 120-400 MeV/u for Carbon Ions, 4e6/10¹⁰ pps); the beam intensity uniformity during the slow extraction process is a fundamental requirement for achieving accurate and fast treatments. CNAO developed an online Fast Intensity Monitor (FIM), not perturbing the extracted beam, capable of measuring beam intensity with a bandwidth of 50kHz and a resolution of 1%. It consists of a thin (0.8 μm) metallic foil that emits secondary electrons when traversed by the beam. The electrons are multiplied by a Channeltron device, polarized at high voltage versus ground. The Channeltron output current is amplified and converted in a Pulse Width Modulated (PWM) signal, which is then decoupled and transmitted to the equipment room, where an FPGA implements a servo-spill. The work presents the detector, the floating electronics, the preliminary measurements with beam and the integration in a closed loop on the synchrotron air-core quadrupole obtaining promising results.

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MOPHA051

Scintillating Fibers used as Profile Monitors for the CNAO HEBT Lines

detector, proton, extraction, vacuum

910

E. Rojatti
UniPV, Pavia, Italy
J. Bosser, M. Haguenauer, P. Poilleux
CERN, Geneva, Switzerland
J. Bosser, G.M.A. Calvi, L. Lanzavecchia, A. Parravicini, M. Pullia, C. Viviani
CNAO Foundation, Milan, Italy
M. Caldara
University of Bergamo, Bergamo, Italy

The CNAO (Centro Nazionale di Adroterapia Oncologica) Foundation is the first Italian center for deep hadrontherapy with Protons and Carbon Ions. Several beam monitors exploiting the scintillation process have been designed to check the beam quality in the extraction lines, in order to guarantee patients safety. The SFH (Scintillating Fibers Harp), the QPM (Qualification Profile Monitor), and the SFP (Scintillating Fibers plus Photodiodes) are made up by two orthogonal scintillating fibers harps with not dead area for the horizontal and the vertical beam profiles measurement. The QPM and the SFH are both installed on the beam line and they use a CCD camera for the signal acquisition. The SFP is a SFH upgrade project aimed to replace the camera with two Photodiodes arrays coupled to the fibers in vacuum. The WD (Watch Dog) detector, not already installed, has been designed to check the beam position through the intensity of the beam tails. It uses two couples of scintillating fibers displaced transversally to the beam direction, coupled to four APDs (Avalanche Photodiodes). This work describes the beam detectors, their achieved performances and the most recent beam measurements.

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MOPTY025

High-current RFQ Design Study on RAON

rfq, emittance, cavity, acceleration

990

J. Bahng, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea
B.H. Choi
IBS, Daejeon, Republic of Korea

Rare isotope Accelerator Of Newness (RAON) heavy ion accelerator has been designed as a facility for a rare isotepe accelerator of the Rare Isotope Science Project (RISP). RAON provides 400 kW CW heavy ion beams from proton to uranium to support researches in various science fields. The RAON system consists of a few ECR ion source, low energy beam transport systems (LEBTs), CW radio frequency quadrupole (RFQ) accelerators, a medium energy beam transport and superconducting linac. We present the design study of the RFQ accelerator from 30 keV/u to 1.5 MeV/u of deuteron beam with meeting a requirement of over 15 mA beam at the target. We optimized the normal conducting CW RFQ accelerator that has a high transmission and a low longitudinal emittance. In this paper, we will present the design result of RFQ beam dynamics studies and its 2D and 3D EM analysis.

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MOPTY082

Beam Instrumentation of the PXIE LEBT Beam Line

emittance, solenoid, ion-source, diagnostics

1129

R.T.P. D'Arcy
UCL, London, United Kingdom
B.M. Hanna, L.R. Prost, V.E. Scarpine, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

The PXIE accelerator is the front-end test stand of the proposed Proton Improvement Plan (PIP-II) initiative: a CW-compatible pulsed H⁻ superconducting RF linac upgrade to Fermilab’s injection system. The PXIE Ion Source and Low-Energy Beam Transport (LEBT) section are designed to create and transfer a 1–10 mA H⁻ beam, in either pulsed (0.001–16 ms) or DC mode, from the ion source through to the injection point of the RFQ. This paper discusses the range of diagnostic tools Allison-type Emittance Scanner, Faraday Cup, Toroid, DCCT, electrically isolated diaphragms – involved in the commissioning of the beamline and preparation of the beam for injection into the RFQ.

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MOPWI003

Laserwire Emittance Scanner at CERN Linac 4

laser, linac, detector, emittance

1146

K.O. Kruchinin, G.E. Boorman, A. Bosco, S.M. Gibson, P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
E. Bravin, T. Hofmann, U. Raich, F. Roncarolo, F. Zocca
CERN, Geneva, Switzerland
A.P. Letchford
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Linac 4 presently under construction at CERN is designed to replace the existing 50 MeV Linac 2 in the LHC injector chain and will accelerate the beam of high current negative hydrogen ions to 160 MeV. During the commissioning a laserwire emittance scanner has been installed allowing noninvasive measuring of the emittance at 3 MeV and 12 MeV setups. A low power infrared fibre coupled laser was focused in the interaction region down to ~150 um and collided with the ion beam neutralising negative ions. At each transverse laser position with respect to the ion beam the angular distribution of the neutral particle beamlets was recorded by scanning a diamond detector across the beamlet at a certain distance from the IP while the main beam of the H⁻ ions was deflected using dipole magnet installed upstream the detector. Measuring the profile of the beamlet by scanning the laser across the beam allows to directly measure the transverse phase-space distribution and reconstruct the transverse beam emittance. In this report we will describe the analysis of the data collected during the 3 MeV and 12 MeV operation of the Linac 4. We will discuss the hardware status and future plans.

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MOPWI006

Development of a Supersonic Gas-jet Monitor to Measure Beam Profile Non-destructively

vacuum, electron, storage-ring, experiment

1157

H.D. Zhang, A. Jeff, V. Tzoganis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Jeff
CERN, Geneva, Switzerland
A. Jeff, V. Tzoganis, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
V. Tzoganis
RIKEN, Saitama, Japan

Funding: This project is supported by Helmholtz Association(VH-NG-328), EU’s 7th Framework Program for research, technological development and demonstration( 215080) and STFC Cockcroft core grant(ST/G008248/1).
The measurement of the transverse beam profile is a great challenge for high intensity, high brightness and high power particle beams due to their destructive power. Current non-destructive methods such as residual gas monitors and beam induced fluorescence monitors either require a rather long integration time or residual gas pressures in the order of 10^-7 mbar to make meaningful measurements. A supersonic gas-jet beam profile monitor has been developed by QUASAR group at the Cockcroft Institute, UK and promises significant improvements over these established techniques. In this monitor, a supersonic gas curtain is generated that crosses the beam to be analyzed under an angle of 45°. When both beams interact, ionization of the gas jet particles occurs and these ions are then accelerated by an electrostatic extraction field towards a Micro Channel Plate (MCP). Beam images are then obtained via a phosphor screen-CCD camera combination. In this contribution, we discuss the monitor design and present beam profile measurements of a 5 keV electron beam. These are complemented by results from measurements using a pulsed valve to study the gas jet dynamics.

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MOPWI009

A Multi-pinhole Faraday Cup Device for Measurement of Discrete Charge Distribution of Heavy and Light Ions

electron, diagnostics, experiment, vacuum

1160

P.K. Roy, S. Dwaraknath, F.U. Naab, S. Taller, O.F. Toader, G. Was
NERS-UM, Ann Arbor, Michigan, USA

It is a difficult task to identify the beam density distribution profile over discrete areas using a standard Faraday cup, as the measurements are provided for the full aperture geometry of the instrument. Ideally, the intensity of the scintillating material would provide a correlation to the beam density, but the low photon efficiency, damage to the scintillator, and camera resolution all limit the practicality of using this system for assessing the spatial resolution of an ion beam. A beam profile monitor (BPM) device has the ability to provide a partial or discrete distribution of an integrated beam profile. The BPM, however, does not discriminate between ions and electrons, the latter of which can be problematic for assessing the full beam profile. To provide a better description of the beam density in spatial dimensions, a multi-pinhole Faraday cup (MPFC) has been designed, developed, and applied to the measurement of energetic ions. This device uses an array of millimeter sized Faraday cups arranged in a grid to measure the current of the beam at discrete locations. This report presents the design of the device, and its performance with ion beams.

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MOPWI023

Development Plan for Physics Application Software for FRIB Driver Linac

linac, software, EPICS, operation

1201

M. Ikegami, G. Shen
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
FRIB is a heavy ion linac facility presently under construction at Michigan State University, USA, and its driver linac accelerates CW beams of all stable ions up to uranium to the energy of 200 MeV/u with the beam power of 400 kW. We plan to start beam commissioning of the driver linac from December 2017. An adequate software environment and infrastructure is critical for our commissioning and operation. Recently, a middle layer based architecture, EPICS V4 based services for example, for physics application has been rapidly developed at other facilities like NSLS II. It has been showing its flexibility, and portability. After reviewing those recent developments, we decided to adopt these services as software infrastructure for FRIB driver linac commissioning. It enables us to take advantage of their cutting edge technologies and maturity as a system sustained by the experience accumulated in the commissioning of NSLS-II. In this paper, we present a plan to develop physics application software for FRIB driver linac based on EPICS V4 services and related software. We also present a plan to adjust these EPICS V4 related software to meet the FRIB specific requirements.

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TUXB2

Upgrade of the Unilac for Fair

DTL, proton, linac, emittance

1281

L. Groening, A. Adonin, R. M. Brodhage, X. Du, R. Hollinger, O.K. Kester, S. Mickat, A. Orzhekhovskaya, B. Schlitt, G. Schreiber, H. Vormann, C. Xiao
GSI, Darmstadt, Germany
H. Hähnel, U. Ratzinger, A. Seibel, R. Tiede
IAP, Frankfurt am Main, Germany

The UNIversal Linear Accelerator (UNILAC) at GSI serves as injector for all ion species from protons to uranium since four decades. Its 10⁸ MHz Alvarez type DTL providing acceleration from 1.4 MeV/u to 11.4 MeV/u has suffered from material fatigue. The DTL will be replaced by a completely new section with almost same design parameters, i.e. pulsed current of up to 15 mA of 238U²⁸⁺ at 11.4 MeV/u. A dedicated terminal & LEBT for operation with 238U⁴⁺ is currently constructed. The uranium sources need to be upgraded in order to provide increased beam brilliances and for operation at 3 Hz. In parallel a 70 MeV / 70 mA proton linac based on H-mode cavities is under design and construction. This contribution will also give a brief summary of the overall status of the FAIR project.

Slides TUXB2 [4.634 MB]

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TUYB2

Accelerator Physics in ERL Based Polarized Electron Ion Collider

electron, linac, luminosity, radiation

1296

Y. Hao
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.

Slides TUYB2 [14.101 MB]

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TUYB3

Progress on the Design of the Polarized Medium-energy Electron Ion Collider at JLab

electron, collider, polarization, luminosity

1302

F. Lin, S.A. Bogacz, P.D. Brindza, A. Camsonne, E. Daly, Y.S. Derbenev, D. Douglas, R. Ent, D. Gaskell, R.L. Geng, J.M. Grames, J. Guo, L. Harwood, A. Hutton, K. Jordan, A.J. Kimber, G.A. Krafft, R. Li, T.J. Michalski, V.S. Morozov, P. Nadel-Turonski, F.C. Pilat, M. Poelker, R.A. Rimmer, Y. Roblin, T. Satogata, M. Spata, R. Suleiman, A.V. Sy, C. Tennant, H. Wang, S. Wang, H. Zhang, Y. Zhang, Z.W. Zhao
JLab, Newport News, Virginia, USA
S. Abeyratne, B. Erdelyi
Northern Illinois University, DeKalb, Illinois, USA
D.P. Barber
DESY, Hamburg, Germany
Y. Cai, Y. Nosochkov, M.K. Sullivan, M.-H. Wang, U. Wienands
SLAC, Menlo Park, California, USA
A. Castilla, J.R. Delayen
ODU, Norfolk, Virginia, USA
Y. Filatov
JINR, Dubna, Russia
J. Gerity, T.L. Mann, P.M. McIntyre, N. Pogue, A. Sattarov
Texas A&M University, College Station, Texas, USA
C. Hyde, K. Park
Old Dominion University, Norfolk, Virginia, USA
A.M. Kondratenko, M.A. Kondratenko
Science and Technique Laboratory Zaryad, Novosibirsk, Russia
P.N. Ostroumov
ANL, Argonne, Illinois, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The Medium-energy Electron Ion Collider (MEIC) at JLab is designed to provide high luminosity and high polarization needed to reach new frontiers in the exploration of nuclear structure. The luminosity, exceeding 1033 cm^-2s⁻¹ in a broad range of the center-of-mass (CM) energy and maximum luminosity above 1034 cm^-2s⁻¹, is achieved by high-rate collisions of short small-emittance low-charge bunches made possible by high-energy electron cooling of the ion beam and synchrotron radiation damping of the electron beam. The polarization of light ion species (p, d, 3He) can be easily preserved and manipulated due to the unique figure-8 shape of the collider rings. A fully consistent set of parameters have been developed considering the balance of machine performance, required technical development and cost. This paper reports recent progress on the MEIC accelerator design including electron and ion complexes, integrated interaction region design, figure-8-ring-based electron and ion polarization schemes, RF/SRF systems and ERL-based high-energy electron cooling. Luminosity performance is also presented for the MEIC baseline design.

Slides TUYB3 [6.245 MB]

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TUBB1

Charge Stripper Development for FRIB

heavy-ion, proton, linac, plasma

1339

F. Marti, P. Guetschow, J.A. Nolen
FRIB, East Lansing, Michigan, USA
A. Hershcovitch, P. Thieberger
BNL, Upton, Long Island, New York, USA
Y. Momozaki, J.A. Nolen, C.B. Reed
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 and NSF grant PHY-1102511
The Facility for Rare Isotope Beams (FRIB) at Michigan State University is building a heavy ion linac to produce rare isotopes by the fragmentation method. The linac will accelerate ions up to U to energies above 200 MeV/u with beam powers up to 400 kW. At energies between 16 and 20 MeV/u the ions will be stripped to higher charge states to increase the energy gain downstream in the linac. The main challenges in the stripper design are due to the high power deposited by the ions in the stripping media (~ 30 MW/cm³) and radiation damage if solids are used. For that reason self-recovering stripper media must be used. The baseline stripper choice is a high-velocity, thin film of liquid lithium with an alternative option of a helium gas stripper. We present in this paper the status of the R&D and construction of the final stripper. Extensive experimental work has been performed on both options.

Slides TUBB1 [3.534 MB]

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TUBB2

The Accelerator Facility of the Facility for Antiproton and Ion Research

target, proton, antiproton, heavy-ion

1343

P.J. Spiller, F. Becker, A. Dolinskyy, L. Groening, O.K. Kester, K. Knie, H. Reich-Sprenger, W. Vinzenz, M. Winkler
GSI, Darmstadt, Germany
D. Prasuhn
FZJ, Jülich, Germany

The accelerators of the Facility for Antiproton and Ion Research – FAIR are under construction. The sophisticated system of accelerators is designed to produce stable and secondary beams with a significant variety of intensities and beam energies. FAIR will explore the intensity frontier of heavy ion accelerators and the beams for the experiments will have highest beam quality for cutting edge physics to be conducted. The main driver accelerator of FAIR will be the SIS100 synchrotron. In order to produce the intense rare isotope beams (RIB) at FAIR, a unique superconducting fragment separator is under construction. A system of storage rings will collect and cool secondary particles from the FAIR. Intense work on test infrastructure for the huge number of superconducting magnets of the FAIR machines is ongoing at GSI and several partner labs. In addition, the GSI accelerator facility is being prepared to serve as injector for the FAIR accelerators. As the construction of the FAIR accelerators and the procurement has started, an overview of the designs, procurements plans and infrastructure preparation can be provided.

Slides TUBB2 [4.653 MB]

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TUPJE079

High Charge Development of the APS Injector for an MBA Upgrade

booster, impedance, vacuum, injection

1828

C. Yao, M. Borland, J.R. Calvey, K.C. Harkay, D. Horan, R.R. Lindberg, N. Sereno, H. Shang, X. Sun, J. Wang
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The APS MBA (multi-bend achromat) upgrade storage ring will employ a “swap out” injection scheme and requires a single-bunch beam with up to 20 nC from the injector. The APS injector, which consists of a 450-MeV linac, a particle accumulator ring (PAR), and a 7-GeV synchrotron (Booster), was originally designed to provide up to 6 nC of beam charge. High charge injector study is part of the APS upgrade R&D that explores the capabilities and limitations of the injector through machine studies and simulations, and identifies necessary upgrades in order to meet the requirements of the MBA upgrade. In the past year we performed PAR and booster high charge studies, implemented new ramp correction of the booster rap supplies, explored non-linear chromatic correction of the booster, etc. This report presents the results and findings.

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TUPMA023

Two-Dimensional Calculation of Channeling Radiation Spectrum for High-Brightness Hard X-Ray Production

electron, radiation, lattice, brightness

1888

W.D. Rush, J. Shi
KU, Lawrence, Kansas, USA

The channeling radiation spectrum is calculated without using the one-dimensional approximation in the planar channeling radiation model or the single-string approximation in the axial channeling radiation model. The obtained spectrum of the two-dimensional channeling radiaiton is significantly different from those previously calculated with the approximations. The calculation presented here is of the channeling radiation experiments conducted at Fermilab Advanced Superconducting Test Accelerator (ASTA) photoinjector with electron beam energies of 20-50 MeV and a diamond target. The computational method developed in this work can be applied to general cases of different crystals and beams with different energy and emittances.

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TUPHA012

LOCO Application to NSLS2 SR Dispersion and Beta Beating Correction

quadrupole, optics, storage-ring, lattice

1989

X. Yang
BNL, Upton, Long Island, New York, USA
X. Huang, J.A. Safranek
SLAC, Menlo Park, California, USA

During the short run in early July, 2014, we made changes to the Matlab LOCO setup for NSLS-II and applied LOCO successfully to the machine. The MML setup was verified with I/O tests for all quadrupole families. The LOCO setup was further tested with an intentional quadrupole error. After the successful LOCO correction, the rms beta beat was reduced from the initial values of 5.5% x and 5.6% y, to 1.9% x and 1.0% y, respectively. The rms horizontal dispersion error was reduced from 21 mm to 6 mm. It is critical to keep the same closed orbit for LOCO correction to take effect. Because presently some correctors are nearly saturated, closed orbit cannot be controlled for additional iterations. We expect LOCO to achieve better optics correction after the orbit control is improved.

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TUPTY025

Betatron Cleaning for Heavy Ion Beams with IR7 Dispersion Suppressor Collimators

proton, heavy-ion, collimation, simulation

2057

P.D. Hermes, R. Bruce, J.M. Jowett, S. Redaelli
CERN, Geneva, Switzerland

The betatron collimators in IR7 constitute the backbone of the collimation system of the LHC. A fraction of the secondary halo protons or heavy-ion fragments, scattered out of the primary collimator, is not captured by the secondary collimators but hit cold magnets in the IR7 dispersion suppressor (DS) where the dispersion starts to increase. A possible approach to reduce these losses is based on the installation of additional collimators in the DS region. In this paper, simulations of the cleaning efficiency for Pb⁸²⁺ ions are used to evaluate the effect of the additional collimators. The results indicate a significant improvement of the heavy-ion cleaning efficiency.

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TUPTY028

Collimator Layouts for HL-LHC in the Experimental Insertions

collimation, luminosity, proton, heavy-ion

2064

R. Bruce, F. Cerutti, L.S. Esposito, J.M. Jowett, A. Lechner, E. Quaranta, S. Redaelli, M. Schaumann, E. Skordis, G.E. Steele
CERN, Geneva, Switzerland
H. Garcia Morales, R. Kwee-Hinzmann
JAI, Egham, Surrey, United Kingdom

This paper presents the layout of collimators for HL-LHC in the experimental insertions. On the incoming beam, we propose to install additional tertiary collimators to protect potential new aperture bottlenecks in cells 4 and 5, which in addition reduce the experimental background. For the outgoing beam, the layout of the present LHC with three physics debris absorbers gives sufficient protection for high-luminosity proton operation. However, collisional processes for heavy ions cause localized beam losses with the potential to quench magnets. To alleviate these losses, an installation of dispersion suppressor collimators is proposed.

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TUPTY047

ERL with Non-Scaling Fixed Field Alternating Gradient Lattice for eRHIC

electron, linac, hadron, collider

2120

D. Trbojevic, J.S. Berg, S.J. Brooks, Y. Hao, V. Litvinenko, C. Liu, F. Méot, M.G. Minty, V. Ptitsyn, T. Roser, P. Thieberger, N. Tsoupas
BNL, Upton, Long Island, New York, USA

Funding: Work performed under Contract Number DE-AC02-98CH10886 with the auspices of the US Department of Energy.
The proposed eRHIC electron-hadron collider uses a "non-scaling FFAG" lattice to recirculate 16 turns of different energy through just two beamlines located in the RHIC tunnel. This paper presents lattices for these two FFAGs that are optimised for low magnet field and to minimise total synchrotron radiation across the energy range. The higher number of recirculations in the FFAG allows a shorter linac (1.322GeV) to be used, drastically reducing cost, while still achieving a 21.2GeV maximum energy to collide with one of the existing RHIC hadron rings at up to 250GeV. eRHIC uses many cost-saving measures in addition to the FFAG: the linac operates in energy recovery mode, so the beams also decelerate via the same FFAG loops and energy is recovered from the interacted beam. All magnets will constructed from NdFeB permanent magnet material, meaning chillers and large magnet power supplies are not needed. This paper also describes a smaller prototype ERL-FFAG accelerator that will test all of these technologies in combination to reduce technical risk for eRHIC.

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TUPTY078

Fixed-energy Cooling and Stacking for an Electron Ion Collider

electron, ECR, space-charge, collider

2214

P.M. McIntyre, S. Assadi, J. Gerity, A. Sattarov
Texas A&M University, College Station, Texas, USA

The proposed designs for polarized-beam electron-ion colliders require cooling of the ion beam to achieve and sustain high luminosity. One attractive approach is to make a fixed-energy storage ring in which ions are con-tinuously cooled and stacked during a collider store, then transferred to the collider and accelerated for a new store when the luminosity decreases. An example design is reported for a 6 GeV/u superferric storage ring, and for a d.c. electron cooling system in which electron space charge is fully neutralized so that high-current magnetized e-cooling can be used to best advantage.

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TUPTY082

Scanning Synchronization of Colliding Bunches for MEIC Project

cavity, controls, electron, collider

2229

Y.S. Derbenev, V.P. Popov
JLab, Newport News, Virginia, USA
Y.D. Chernousov
ICKC, Novosibirsk, Russia
G.M. Kazakevich
Euclid TechLabs, LLC, Solon, Ohio, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
Synchronization of colliding beams is one of the major issues of an electron-ion collider (EIC) design because of sensitivity of ion revolution frequency to beam energy. A conventional solution for this trouble is insertion of bent chicanes in the arcs space. In our report we consider a method to provide space coincidence of encountering bunches in the crab-crossing orbits Interaction Region (IR) while repetition rates of two beams do not coincide. The method utilizes pair of fast kickers realizing a bypass for the electron bunches as the way to equalize positions of the colliding bunches at the Interaction Point (IP). A dipole-mode warm or SRF cavities fed by the magnetron transmitters are used as fast kickers, allowing a broad-band phase and amplitude control. The proposed scanning synchronization method implies stabilization of luminosity at a maximum via a feedback loop. This synchronization method is evaluated as perspective for the Medium Energy Electron-Ion collider (MEIC) project of JLab with its very high bunch repetition rate.

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TUPWI003

Proton Beam Applications for Silicon Bulk Micromachining

proton, experiment, linac, quadrupole

2241

P. Nenzi, G. Bazzano, F. Marracino, L. Picardi, C. Ronsivalle, V. Surrenti, M. Vadrucci
ENEA C.R. Frascati, Frascati (Roma), Italy
F. Ambrosini
University of Rome La Sapienza, Rome, Italy
F. Ambrosini
Università di Roma "La Sapienza", SAPIENZA-DIET, Roma, Italy
M. Balucani, A. Klyshko
University of Rome "La Sapienza", Rome, Italy
C. Snels, M. Tucci
ENEA Casaccia, Roma, Italy

The irradiation of silicon with ion beams is an established technique to modify its properties. Protons are used for micromachining applications, in conjunction with porous silicon. Porous silicon does not form in areas irradiated with a given fluence of protons (>10¹⁴ cm^-2). Our work concentrated on the applicability of masked irradiation of silicon wafers with 1.8 MeV proton beams delivered by the TOP-IMPLART LINAC. In our experiments 1-10 Ω*cm n,p-type silicon wafers were masked and irradiated with protons at fluences between 10¹⁴ and 10¹⁵ protons/cm². Porous silicon did not form in the irradiated areas up to a distance from the surface corresponding to the stopping range (30um). The suppression of porous silicon formation is due to the to the neutralization of dopant impurities by implanted protons that increases the local resistivity. The interest in using RF LINAC for micromachining applications lies in the possibility of deep implantation, that allows the realization of 3D structures for MEMS applications. The use of metal masks with uniform beams, instead of scanned micro- and nano-metric ion probes, increases throughput achievable in industrial processing of wafers.

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TUPWI021

Progress on a 30 - 350 MeV Normal-Conducting Scaling FFAG for Proton Therapy

proton, lattice, injection, extraction

2285

J.M. Garland, R.B. Appleby, H.L. Owen, S.C. Tygier
UMAN, Manchester, United Kingdom

Funding: Work supported by the STFC (UK) under grant no. ST/K002503/1
We present our progress on a new design for a 30 - 350 MeV scaling FFAG for proton therapy and tomography - NORMA (NOrmal-conducting Racetrack Medical Accelerator) which allows the realisation of proton computed tomography (pCT) and utilises normal conducting magnets in both a circular and racetrack configuration which are designed using advanced optimisation algorithms developed in PyZgoubi. The ring and racetrack configurations have average circumferences of around 60 and 70 m respectively, peak magnetic fields of < 1.8 T, average orbit excursions < 50 cm and dynamic aperture calculations of > 50 mm.mrad using a novel technique. The racetrack design has a total magnet-free straight length of 4.9 m at two opposing points, designed to ease injection and extraction systems.

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TUPWI029

Baseline Scheme for Polarization Preservation and Control in the MEIC Ion Complex

polarization, collider, controls, solenoid

2301

V.S. Morozov, Y.S. Derbenev, F. Lin, Y. Zhang
JLab, Newport News, Virginia, USA
Y. Filatov
MIPT, Dolgoprudniy, Moscow Region, Russia
A.M. Kondratenko, M.A. Kondratenko
Science and Technique Laboratory Zaryad, Novosibirsk, Russia

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The scheme for preservation and control of the ion polarization in the Medium-energy Electron-Ion Collider (MEIC) has been under active development in recent years. The figure-8 configuration of the ion rings provides a unique capability to control the polarization of any ion species including deuterons by means of "weak" solenoids rotating the particle spins by small angles. Insertion of "weak" solenoids into the magnetic lattices of the booster and collider rings solves the problem of polarization preservation during acceleration of the ion beam. Universal 3D spin rotators designed on the basis of "weak" solenoids allow one to obtain any polarization orientation at an interaction point of MEIC. This paper presents the baseline scheme for polarization preservation and control in the MEIC ion complex.

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TUPWI031

Status of the MEIC Ion Collider Ring Design

electron, collider, dipole, optics

2307

V.S. Morozov, Y.S. Derbenev, L. Harwood, A. Hutton, F. Lin, F.C. Pilat, Y. Zhang
JLab, Newport News, Virginia, USA
Y. Cai, Y. Nosochkov, M.K. Sullivan, M.-H. Wang, U. Wienands
SLAC, Menlo Park, California, USA
J. Gerity, T.L. Mann, P.M. McIntyre, N. Pogue, A. Sattarov
Texas A&M University, College Station, Texas, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported in part by the US DOE Contract No. DE-AC02-76SF00515.
We present an update on the design of the ion collider ring of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The design is based on the use of super-ferric magnets. It provides the necessary momentum range of 8 to 100 GeV/c for protons and ions, matches the electron collider ring design using PEP-II components, fits readily on the JLab site, offers a straightforward path for a future full-energy upgrade by replacing the magnets with higher-field ones in the same tunnel, and is more cost effective than using presently available current-dominated super-conducting magnets. We describe complete ion collider optics including an independently-designed modular detector region.

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TUPWI032

Progress on Optimization of the Nonlinear Beam Dynamics in the MEIC Collider Rings

sextupole, optics, distributed, dynamic-aperture

2311

Y. Nosochkov, Y. Cai, M.K. Sullivan, M.-H. Wang, U. Wienands
SLAC, Menlo Park, California, USA
Y.S. Derbenev, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under US DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported by the US DOE Contract DE-AC02-76SF00515.
One of the key design features of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab is a small beta function at the interaction point (IP) allowing one to achieve a high luminosity of up to 10³⁴ cm^-2s^-1. The required strong beam focusing unavoidably causes large chromatic effects such as chromatic tune spread and beam smear at the IP, which need to be compensated. This paper reports recent progress in our development of a chromaticity correction scheme for the ion ring including optimization of dynamic aperture and momentum acceptance.

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TUPWI034

Capture, Acceleration and Bunching RF Systems for the MEIC Booster and Storage Rings

cavity, collider, electron, bunching

2318

S. Wang, J. Guo, F. Lin, V.S. Morozov, R.A. Rimmer, H. Wang, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
The MEIC, proposed by Jefferson Lab, consists of a series of accelerators. The electron collider ring accepts electrons from CEBAF at energies from 3 to 12 GeV. Protons and ions are delivered to a booster and captured in a long bunch before ramping and transfer to the ion collider ring. The ion collider ring accelerates a small number of long ion bunches to colliding energy before they are re-bunched into a high frequency train of very short bunches for colliding. Two sets of low frequency RF systems are needed for the long ion bunch energy ramping in the booster and ion collider ring. Another two sets of high frequency RF cavities are needed for re-bunching in the ion collider ring and compensating synchrotron radiation energy loss in the electron collider ring. The requirements from energy ramping, ion beam bunching, electron beam energy compensation, collective effects, beam loading and feedback capability, RF power capability, etc. are presented. The preliminary designs of these RF systems are presented. Concepts for the baseline cavity and RF station configurations are described, as well as some options that may allow more flexible injection and acceleration schemes.

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TUPWI035

MEIC Proton Beam Formation with a Low Energy Linac

booster, collider, linac, proton

2322

Y. Zhang
JLab, Newport News, Virginia, USA

The MIEC proton and ion beams are generated, accumulated, accelerated and cooled in a new green-field ion injector complex designed specifically to support its high luminosity goal. This injector consists of sources, a linac and a small booster ring. In this paper we explore feasibility of a short ion linac that injects low energy protons and ions into the booster ring.

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TUPWI037

Electron Cooling Study for MEIC

electron, proton, emittance, solenoid

2326

H. Zhang, Y.S. Derbenev, D. Douglas, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and No. DE-AC02-06CH11357.
Electron cooling of the ion beams is one critical R&D to achieve high luminosities in JLab’s MEIC proposal. In the present MEIC design, a multi-staged cooling scheme is adapted, which includes DC electron cooling in the booster ring and bunched beam electron cooling in the collider ring at both the injection energy and the collision energy. We explored the feasibility of using both magnetized and non-magnetized electron beam for cooling, and concluded that a magnetized electron beam is necessary. Electron cooling simulation results for the newly updated MEIC design is also presented.

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TUPWI038

A High Energy e-p/A Collider Based on CepC-SppC

proton, electron, collider, luminosity

2329

Y. Zhang
JLab, Newport News, Virginia, USA
Y.M. Peng
IHEP, Beijing, People's Republic of China

Construction of CepC and SppC, the proposed future energy frontier circular e⁺e⁻ and pp colliders in China, provides an opportunity to realize e-p or e-A collisions in a CM energy range up to 4.1 TeV. This paper presents a preliminary conceptual design of this e-p/A collider. The design parameters and anticipated luminosities will be given. We also discuss staging approaches to realize this collider with a low cost and at an earlier time.

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TUPWI039

Modeling Crabbing Dynamics in an Electron-Ion Collider

electron, proton, betatron, collider

2333

A. Castilla, J.R. Delayen, T. Satogata
ODU, Norfolk, Virginia, USA
A. Castilla, J.R. Delayen, V.S. Morozov, T. Satogata
JLab, Newport News, Virginia, USA
A. Castilla
DCI-UG, León, Mexico

Funding: *Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A local crabbing scheme requires π/2 (mod π) horizontal betatron phase advances from an interaction point (IP) to the crab cavities on each side of it. However, realistic phase advances generated by sets of quadrupoles, or Final Focusing Blocks (FFB), between the crab cavities located in the expanded beam regions and the IP differ slightly from π/2. To understand the effect of crabbing on the beam dynamics in this case, a simple model of the optics of the Medium Energy Electron-Ion Collider (MEIC) including local crabbing was developed using linear matrices and then studied numerically over multiple turns (1000 passes) of both electron and proton bunches. The same model was applied to both local and global crabbing schemes to determine the linear-order dynamical effects of the synchro-betatron coupling induced by crabbing.

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TUPWI051

Study of Orbit Correction for eRHIC FFAG Design

lattice, simulation, electron, alignment

2366

C. Liu, Y. Hao, V. Litvinenko, F. Méot, M.G. Minty, V. Ptitsyn, D. Trbojevic
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The chromaticities in the eRHIC linear non-scaling Fixed Field Alternating Gradient (FFAG) lattice are very large. Therefore, particles will decohere in phase space given the presence of lattice errors. The decoherence causes a deviation of the orbit response which is the basis for orbit corrections. In this report we will present a study of the linearity of the orbit response in a lattice with large chromaticity, a comparison of the results of orbit corrections for several cases together with a conclusion that correcting the average orbit with a measured orbit response works as good as an orbit correction for on-momentum particles.
The work was performed under Contract No. DE-AC02-98CH10886
with the U.S. Department of Energy.

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TUPWI059

Influence of Plasma Loading in a Hybrid Muon Cooling Channel

plasma, electron, cavity, emittance

2381

D. Stratakis
BNL, Upton, Long Island, New York, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
K. Yonehara
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In a hybrid 6D cooling channel, cooling is accomplished by reducing the beam momentum through ionization energy loss in wedge absorbers and replenishing the momentum loss in the longitudinal direction with gas-filled rf cavities. While the gas acts as a buffer to prevent rf breakdown, gas ionization may also occur as the beam passes through a HPRF cavity. The resulting plasma, may gain substantial energy from the rf electric field which it can transfer via collisions to the gas, an effect known as plasma loading. In this paper, we investigate the influence of plasma loading on the cooling performance of a rectilinear hybrid channel. With the aid of numerical simulations we examine the sensitivity in cooling performance and plasma loading to key parameters such as the rf gradient and gas pressure.

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WEXC1

Machine and Personnel Protection for High Power Hadron Linacs

linac, radiation, hadron, controls

2418

M. Ikegami
FRIB, East Lansing, Michigan, USA

Machine and personnel safety are increasingly important for high power hadron linacs as involved beam power increases. Design requirements and characteristic features of machine protection system and personnel protection system for operating and proposed high power hadron linacs, such as J-PARC, SNS, FRIB, ESS, and IFMIF, are reviewed.

Slides WEXC1 [9.859 MB]

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WEPWA012

Design of a Microwave Frequency Sweep Interferometer for Plasma Density Measurements in ECR Ion Sources

plasma, simulation, diagnostics, ion-source

2512

G. Torrisi, R. Agnello, G. Castro, L. Celona, V. Finocchiaro, S. Gammino, D. Mascali, L. Neri, S. Passarello
INFN/LNS, Catania, Italy
T. Isernia, G. Torrisi
Universitá Mediterranea di Reggio Calabria, Reggio Calabria, Italy
G. Sorbello
University of Catania, Catania, Italy

Electron Cyclotron Resonance Ion Sources (ECRIS) are among the candidates to support the growing request of intense beams of multicharged ions. Their further development is related to the availability of new diagnostic tools, nowadays consisting of few types only of devices designed on purpose for such compact machines. Microwave Interferometry is a non-invasive method for plasma diagnostics and represents the best candidate for the whole plasma density measurements. Interferometry in ECR Ion Sources is a challenging task due to their compact size. The typical density range of ECR plasmas (10¹¹-10¹² cm^-3) causes the probing beam wavelength to be in the order of few centimetres, which is comparable to the chamber radius. The paper describes the design of a new microwave interferometer based on the so-called "frequency sweep" method: the density is here derived by the frequency shift of a beating signal obtained during the fast sweep of both probing and reference microwave signals; inner cavity multipaths contributions can thereby be suppressed by cleaning the spurious frequencies from the beating signal spectrum.

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WEPWA025

RF Acceleration of Ions Produced by Short Pulse Laser

laser, rfq, experiment, bunching

2548

Y. Fuwa, M. Hashida, Y. Iwashita, S. Sakabe, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
M. Okamura
BNL, Upton, Long Island, New York, USA
A. Yamazaki
Nagoya University, Nagoya, Japan

Funding: This work was supported by Grant-in-Aid for Exploratory Research Number 23654085.
RF acceleration of ions produced by short pulse laser is investigated. An RF cavity is prepared for the acceleration. Some experimental results will be presented.

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WEPWA027

Gas Flow Influence on Negative Hydrogen Ion Generation within the Microwave-Driven Negative Ion Source

ion-source, electron, operation, experiment

2555

S.X. Peng, J.E. Chen, Z.Y. Guo, H.T. Ren, Y. Xu, A.L. Zhang, J.F. Zhang, T. Zhang, J. Zhao
PKU, Beijing, People's Republic of China
J. Zhao
State Key Laboratory of Nuclear Physics and Technology, Beijing, Haidian District, People's Republic of China

H⁻ ion was generated through two processes within a volume Cs- free source. The density of molecule hydrogen gas will impact the electron temperature within the primary discharge chamber that will influence the population of vibrationally excited H2*. Within the extraction region, the interaction between molecule hydrogen and H⁻ ion will is cause the dissociation of negative ion. To better understand the gas flow influence on H⁻ ion generation within a volume negative ion source, a new Cs-free volume microwave-driven H⁻ source body with two gas inlets was developed at Peking University (PKU). Experiment on gas flow and gas pressure distribution within the plasma chamber was carried out with this source body. In the meantime a two dimensional (2D) model for gas flow was developed. Details will be presented in this paper.
[1] S.X. Peng, H.T. Ren, Y. Xu, T. Zhang, etc., CW/Pulsed H⁻ Ion Beam Generation with PKU Cs-free 2.45 GHz Microwave Driven Ion Source. O5-06, NIBS 2014, Accepted for publication in AIP, 2014/11/04.

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WEPWA031

A Compact Multiply Charged Ion Source for Hadrontherapy Facility

plasma, injection, ion-source, solenoid

2563

L. Celona, L. Andò, G. Castro, F. Chines, G. Ciavola, S. Gammino, O. Leonardi, D. Mascali, L. Neri, D. Nicolosi, F. Noto, F. Romano, G. Torrisi
INFN/LNS, Catania, Italy
G. Ciavola
CNAO Foundation, Milan, Italy
G. Torrisi
Universitá Mediterranea di Reggio Calabria, Reggio Calabria, Italy

The ion sources, required by medical applications, must provide intense ion beams, with high reproducibility, stability and brightness. AISHa (Advanced Ion Source for Hadrontherapy) is a compact ECRIS whose hybrid magnetic system consists of a permanent Halbach-type hexapole magnet and a set of independently energized superconducting coils. These will be enclosed in a compact cryostat with two cryocoolers to operate without LHe. The microwave injection system has been designed for maximizing the beam quality through a fine frequency tuning within the 17.3-18.4 GHz band which is possible by using an innovative variable frequency klystron. The introduction of an integrated oven will allow the production of metal ions beams with relatively high intensity. “Accel-decel” extraction system will be used. The LEBT line will consist of a solenoid and a 90° dipole for ions selection. Two diagnostic boxes, made of Faraday cups, beam wires and slits, will allow the investigation of the beam composition and its properties. Moreover, a system of scintillating screens and CCD cameras, placed after the solenoid will allow the investigation of the Frequency Tuning Effect on the source performances.

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WEPWA041

Plans for a Linear Paul Trap at Rutherford Appleton Laboratory

multipole, quadrupole, plasma, resonance

2590

D.J. Kelliher, S. Machida, D.C. Plostinar, C.R. Prior, S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

For over a decade, Linear Paul Traps (LPT) have been used in the study of accelerator beam dynamics. LPT studies exploit the similarity of the Hamiltonian with that of a beam in a quadrupole channel while having advantages in the flexibility of parameter choice, compactness and low cost. In collaboration with Hiroshima University, LPT research planned at STFC Rutherford Appleton Laboratory in the UK aims to investigate a range of topics including resonance crossing, halo formation, long-term stability studies and space-charge effects. Initially, a conventional quadrupole-based LPT will be built at RAL and used for a variety of experiments. In parallel, a design for a more advanced LPT that incorporates higher order multipoles will be pursued and later constructed. This multipole trap will allow non-linear lattice elements to be simulated and so broaden considerably the range of experiments that can be conducted. These will include the investigation of resonance crossing in non-linear lattices, a more detailed study of halo formation and the effect of detuning with amplitude. In this paper we report on progress made in the project to date and future plans.

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WEPWA059

RF Plasma-Based Ion Source Modeling on Unstructured Meshes

simulation, ion-source, plasma, electron

2637

S.A. Veitzer, K.R.C. Beckwith, M. Kundrapu
Tech-X, Boulder, Colorado, USA

Funding: This work was performed under the auspices of the Department of Energy, Office of Basic Energy Sciences Award #DE-SC0009585.
Ion source performance for accelerators and industrial applications can be improved through detailed numerical modeling and simulation. There are a number of technical complexities with developing robust models, including a natural separation of important time scales (rf, electron and ion motion), inclusion of plasma chemistry, and surface effects such as secondary electron emission and sputtering. Due to these computational requirements, it is typically difficult to simulate ion sources with Particle-In-Cell codes. An alternative is to use fluid-based codes coupled with electromagnetics in order to model ion sources. These types of models can simulate plasma evolution and rf-driven flows while maintaining good performance. We show here recent results on modeling the H⁻ ion source for the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) using the fluid plasma modeling code USim. We present new meshing capabilities for generating and parallelizing unstructured computational meshes that have increased our parallel code performance and enabled us to model inductively coupled plasmas for long periods of operation.

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WEPWA063

Beam-Plasma Effects in Muon Ionization Cooling Lattices

plasma, simulation, electron, space-charge

2649

J.S. Ellison, P. Snopok
IIT, Chicago, Illinois, USA

Funding: Work is supported by the U.S. Department of Energy.
New computational tools are essential for accurate modeling and simulation of the next generation of muon based accelerator experiments. One of the crucial physics processes specific to muon accelerators that has not yet been implemented in any current simulation code is beam induced plasma effect in liquid, solid, and gaseous absorbers. We report here on the progress of developing the required simulation tools and applying them to study the properties of plasma and its effects on the beam in muon ionization cooling channels.

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WEPJE001

Optimal Positron-Beam Excited Plasma Wakefields in Hollow and Ion-Wake Channels

plasma, electron, positron, wakefield

2674

A. A. Sahai, T.C. Katsouleas
Duke ECE, Durham, North Carolina, USA

Funding: DE-SC-0010012, NSF-PHY-0936278
A positron-beam interacting with the plasma electrons drives radial suck-in, in contrast to an electron-beam driven blow-out in the over-dense regime, n_b>n₀. In a homogeneous plasma, the electrons are radially sucked-in from all the different radii. The electrons collapsing from different radii do not simultaneously compress on-axis driving weak fields. A hollow-channel allows electrons from its channel-radius to collapse simultaneously exciting coherent fields *. We analyze the optimal channel radius. Additionally, the low ion density in the hollow allows a larger region with focusing phase. We have shown the formation of an ion-wake channel behind a blow-out electron bubble-wake. Here we explore positron acceleration in the over-dense regime comparing an optimal hollow-plasma channel to the ion-wake channel **. The condition for optimal hollow-channel radius is also compared. We also address the effects of a non-ideal ion-wake channel on positron-beam excited fields.
* S Lee, T Katsouleas, Phys. Rev. E, vol 64, 045501(R) (2001)
** A A Sahai, T Katsouleas, Non-linear ion-wake excitation by ultra relativistic electron wakefields, in review (http://arxiv.org/pdf/1504.03735v1.pdf)

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WEPJE011

High Reliability, Long Lifetime, Continuous Wave H⁻ Ion Source

ion-source, electron, plasma, extraction

2695

P. Barrows, G.E. Becerra
PNL, Madison, Wisconsin, USA

Funding: Small Business Innovation Research (SBIR) Phase II
Phoenix Nuclear Labs (PNL) is developing a high-current, long-lifetime negative hydrogen (H⁻) ion source in partnership with Fermilab as part of an ion beam injector for future Intensity Frontier particle accelerators. In this application, continuous output with long lifetime and high reliability and efficiency are critical. Existing ion sources at Fermilab rely on plasma-facing electrodes and are limited to lifetimes of a few hundred hours, while requiring relatively high gas loads on downstream components. PNL's H⁻ ion source uses an electrodeless microwave plasma generator which has been extensively developed in PNL's positive ion source systems, demonstrating 1000+ hours of operation and >99% continuous uptime. A magnetic filter preferentially blocks energetic electrons produced in the plasma, while allowing cold electrons and fast neutrals through toward a cesiated surface converter to produce the desired H⁻ ions, which are extracted into a low energy beam using electrostatic lenses. The design specifications are 5-10 mA of continuous H⁻ current at 30 keV with <0.2 pi-mm-mrad beam emittance. Construction and testing of the H⁻ ion source is underway at PNL.

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WEPMA018

Status of the Ring RF Systems for FAIR

cavity, operation, antiproton, PLC

2789

M. Frey, R. Balß, C. Christoph, O. Disser, G. Fleischmann, U. Hartel, P. Hülsmann, S. Jatta, A. Klaus, H. Klingbeil, H.G. König, U. Laier, D.E.M. Lens, D. Mondry, K.-P. Ningel, H. Richter, S. Schäfer, C. Thielmann, T. Winnefeld, B. Zipfel
GSI, Darmstadt, Germany
K. Groß, H. Klingbeil
TEMF, TU Darmstadt, Darmstadt, Germany

For the FAIR (Facility for Antiproton and Ion Research) synchrotron SIS100 and the storage ring CR (Collector Ring), different RF cavity systems are currently being realized. In addition to the standard RF bucket generation and acceleration, these ring RF systems also allow more complex beam manipulations such as barrier bucket operation or bunch rotation in phase space. Depending on their purpose, the cavities are either loaded with ferrite material or with MA (Magnetic Alloy) ring cores. Independent of the type of cavity, a complete cavity system consists of the cavity itself, a tetrode-based power amplifier, a solid-state pre-amplifier, a supply unit including PLC (Programmable Logic Control), and an RF control system (so-called LLRF, low level RF system). In this contribution, the different systems are described, and their current status is presented.

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WEPMA023

Advanced Multipoles and Appropriated Measurement Tools for Field Characterization of SIS100 Magnets

multipole, dipole, vacuum, superconducting-magnet

2805

P. Schnizer, E.S. Fischer, A. Gottsmann, F. Kaether, A. Mierau, H.G. Weiss
GSI, Darmstadt, Germany
B. Schnizer
TUG/ITP, Graz, Austria

The heavy ion synchrotron SIS100 utilises fast ramped superconducting magnets. Describing and measuring these magnets requires advanced multipoles next to well adapted measurement techniques. We cover briefly the required theory adapted to the measurements, show which designs were available and which decisions had to be taken for measuring curved superconducting magnets. The series of SIS100 dipole magnets is going to be produced. These magnets will be measured at GSI. We present the foreseen field measurement procedure, outline the currently ongoing tests and give our calibration strategy.

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WEPMA024

System Design for a Deterministic Bunch-to-Bucket Transfer

synchrotron, simulation, LLRF, timing

2809

T. Ferrand
TEMF, TU Darmstadt, Darmstadt, Germany
J.N. Bai
IAP, Frankfurt am Main, Germany

Funding: Supported by GSI and the Technical University Darmstadt in the frame of the cooperation for FAIR.
A deterministic bunch to bucket transfer system is currently under development in the frame of the FAIR project at GSI. To achieve our accuracy and stability requirements, a set of hardware modules will be implemented. These hardware modules are expected to provide values such as the relative phase advance between the RF systems of both, the source and the target synchrotron according to an external timing system. These values are exchanged via optical fibers between different supply rooms, and the considered RF signals are re-synthesized locally. These re-synthesized signals are synchronized to enable a precise phase advance control between the synchrotrons’ RF systems. The first step of the development consists in modeling the actual DDS and DSP-based LLRF environment of the SIS18 under Ptolemy-II. Measurements on real devices will be performed concurrently to the simulation. We expect to use this simulation to refine our timing expectations regarding the synchronization process and the inter-module communication protocols and design the synchronization function, which will be implemented on the hardware modules.

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WEPMA034

Bakeout Concept for the HESR at FAIR

dipole, vacuum, heavy-ion, controls

2832

H. Jagdfeld, N. Bongers, P. Chaumet, F.M. Esser, F. Jordan, F. Klehr, G. Langenberg, U. Pabst, L. Semke
FZJ, Jülich, Germany

Forschungszentrum Jülich has taken the leadership of a consortium being responsible for the design of the High-Energy Storage Ring (HESR) going to be part of the FAIR project at GSI. The HESR is designed for antiprotons but can be used for heavy ion experiments as well. Therefore the vacuum is expected to be 10^-11 mbar or better. To achieve this also in the curved sections where 44 bent dipole magnets with a length of around 4.5 m will be installed, NEG coated dipole chambers will be used to reach the needed pumping speed and capacity. For activation of the NEG-material a bakeout system must be installed. The bakeout concept including the layout of the control system and the systematization of the heater packages for all components of the vacuum system are presented. Also the special design of the heater jackets inside the dipole will be shown where the geometrical parameters are very critical and space is very limited. The results of the simulation of temperature distribution in the dipole iron are compared to temperature measurements carried out at a testbench with different layouts of the heater jackets. The final design of the dipole heater jackets will be illustrated.

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WEPMA057

Development of HTS magnets

dipole, neutron, cyclotron, target

2905

K. Hatanaka, M. Fukuda, K. Kamakura, T. Saito, H. Ueda, Y. Yasuda, T. Yorita
RCNP, Osaka, Japan

We have been developing magnets utilizing high-temperature superconducting (HTS) wires for this decade. We built three model magnets, a mirror coil for an ECR ion source, a set of coils for a scanning magnet and a super-ferric dipole magnet to generate magnetic field of 3 T. They were excited with AC/pulse currents as well as DC currents. Recently we fabricated a cylindrical magnet for a practical use which polarizes ultracold neutrons (UCN). It consists of 10 double pancakes and the field strength at the center is higher than 3.5 T which is required to fully polarize 210 neV neutrons. It was successfully cooled and excited. The magnet was used to polarized UCN generated by the RCNP-KEK superthermal UCN source, One dipole magnet has been manufactured which is used as a switching magnet after the RCNP ring cyclotron and is excited by pulse currents. It becomes possible to deliver beams to two experimental halls by time sharing. Their designs and performances are presented in the talk.

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WEPMN021

Design and Research of Secondary Electron Emission Test Equipment with Low Electron Energy

electron, gun, vacuum, accumulation

2970

Y.H. Xu, L. Fan, Y.Z. Hong, X.T. Pei, J. Wang, Y. Wang, W. Wei, B. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

In particle accelerators, the secondary electrons resulting from the interaction between particles and vacuum chamber have a great impact on beam quality. Especially for positron, proton and heavy ion accelerators, massive electrons lead to electron cloud, which affects the stability, energy, emittance and beam life adversely. We have studied the secondary electron emission (SEE) of metal used for accelerators. A secondary electron emission measurement system with low electron energy has been designed and used to measure the SEE yield of metal and non-evaporable getter materials. With the equipment, we have obtained the characteristic of the SEE yield of stainless steel and oxygen free copper (OFC).

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WEPMN024

Exploration of Multi-fold Symmetry Element-loaded Superconducting Radio Frequency Structure for Reliable Acceleration of Low- & Medium-Beta Ion Species

cavity, acceleration, SRF, RF-structure

2978

S.C. Huang
IMP/CAS, Lanzhou, People's Republic of China
R.L. Geng
JLab, Newport News, Virginia, USA

Reliable acceleration of low- to medium-beta proton or heavy ion species is needed for future high current superconducting radio frequency accelerators. Due to the high-Q nature of a superconducting RF resonator, it is sensitive to many factors such as loading variation (from either the accelerated beam or from parasitic field emitted electrons), mechanical vibration, and liquid helium bath pressure fluctuation etc. To increase the stability against those factors, a mechanically strong and stable RF structure is desirable. Guided by this consideration, multi-fold symmetry element-loaded superconducting radio frequency structures, cylindrical tanks with multiple (n>=3) rod-shaped radial elements, are being explored. The top goal of its optimization is to improve mechanical stability. A natural consequence of this structure is a lowered ratio of the peak surface electromagnetic field to the acceleration gradient as compared to the traditional spoke cavity. A disadvantage of this new structure is an increased size for a fixed resonant frequency and optimal beta. This paper describes the optimization of EM design and preliminary mechanical analysis for such structures.

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WEPMN025

Harmonic Resonant Kicker Design for the MEIC Electron Circular Cooler Ring

cavity, electron, impedance, kicker

2981

Y.L. Huang
IMP/CAS, Lanzhou, People's Republic of China
R.A. Rimmer, H. Wang, S. Wang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S.DOE Contract No. DE-AC05-06OR23177.
Bunched-beam electron cooling of the high-energy ion beam emittance may be a crucial technology for the proposed Medium energy Electron Ion Collider (MEIC) to achieve its design luminosity. A critical component is a fast kicker system in the Circular Ring (CR) that periodically switches electron bunches in and out of the ring from and to the driver Energy Recovery Linac (ERL). Compared to a conventional strip-line type kicker, a quarter wave resonator (QWR) based deflecting structure has a much higher shunt impedance and so requires much less RF power. The cavity has been designed to resonate simultaneously at many harmonic modes that are integer multiples of the fundamental mode. In this way the resulting waveform will kick only a subset of the circulating bunches. In this paper, analytical shunt impedance optimization, the electromagnetic simulations of this type of cavity, as well as tuner and coupler concept designs to produce 5 odd and 5 even harmonics of 47.63MHz will be presented, in order to kick every 10th bunch in a 476.3 MHz bunch train.

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WEPMN052

A New RF Laboratory for Developing Accelerator Cavities at the University of Huelva

cavity, heavy-ion, rfq, network

3046

I. Martel, C. Bonțoiu, J.A. Dueñas, D. Gordo-Yáñez, A.K. Orduz, J. Sanchez-Segovia
University of Huelva, Huelva, Spain

The University of Huelva is presently involved in R&D projects for developing RF accelerator cavities. Two types of cavities are presently under design, a prototype of room temperature RFQ injector and a quarter-wave resonator for high intensity heavy-ion linear accelerators. The laboratory is equipped with dedicated test-bench for RF measurements, which includes high-power RF generators, network analyzer, amplifiers and power meters. A clean room is also available having a dedicated space for high-precision mechanical metrology and cavity mounting, together with a vertical cryostat for superconducting cavity test.

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WEPMN057

Calculation and Design of a RF Cavity for a Novel Compact Superconducting Cyclotron for Radioisotope Production

cavity, cyclotron, focusing, simulation

3055

D. Gavela, J. Calero, L. García-Tabarés, A. Guirao, D. Obradors-Campos, C. Oliver, J.M. Pérez Morales, I. Podadera, F. Toral
CIEMAT, Madrid, Spain

Funding: Work partially funded by CDTI and the Spanish Ministry of Economy and Competitiveness, under the subprogram CENIT, project AMIT, reference CEN-20101014
The AMIT cyclotron will be a 8.5 MeV, 10 microAmp, CW, H⁻ accelerator for the purpose of radioisotope production. It includes a superconducting, weak focusing, 4 T magnet, which allows for a low extraction radius and a compact design. The RF cavity design has to deal with challenging requirements: high electric fields created by the required accelerating voltage (60 kV – 70 kV) on a small gap, a small aperture of the magnet leading to high capacitances and thermal losses, and a requirement for a low overall size of the cavity. A quarter wave resonator with one dee (two acceleration gaps) design was chosen. Calculations with HFSS have been performed to compute the resonant frequency, tuners sensitivity, S-parameters, power losses and geometry for input coupler and pickup. A structural Ansys model has been used to analyze the stresses and the deformations of the cavity. A thermal Ansys model was used for the design of the cooling circuits and the calculation of the temperature distribution. Finally, the fluid dynamics of the cooling circuits have been carefully studied. The results of these calculations and the consequent design decisions are presented in this paper.

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WEPHA009

Propagation of Radioactive Contaminants Along the Isolde Beamline

vacuum, target, simulation, proton

3115

R. Kersevan, M. Ady, A. Dorsival, A. Gottberg, M. Maietta, G. Vandoni
CERN, Geneva, Switzerland

The vacuum system of RIB facilities is entirely hermetical, with storage of effluents and controlled release to atmosphere after a decay time. In Isolde, distributed primary pumping is sectorized in three parts, but all effluents are conveyed together in a unique tank. Thus, highly contaminated gas from the target and front end may be mixed with less contaminated gas from the beam transfer lines. This study aims at analysing and quantifying the distribution and propagation of neutral rare gas radioactive isotopes along the Isolde beam-line by numerical simulation (steady-state and time resolved Test-Particle Monte-Carlo, Molflow+) and experimental means. The time-resolved Monte-Carlo integrates decay time for the propagating species. To measure the distribution of contaminants, sampling filters are installed at the exhaust of the vacuum turbo-molecular pumps. Comparison between simulation and experiment shows excellent agreement, confirming the pertinence of the Monte-Carlo tool to radioactive species propagation. The filtering effect of magnetic sectors, the RFQ Cooler, and Buncher on the propagating neutral isotopes are quantified.

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WEPHA010

The Vacuum System of the Extra-Low Energy Antiproton Decelerator ELENA at CERN

vacuum, antiproton, dipole, electron

3119

R. Kersevan
CERN, Geneva, Switzerland

The Extra-Low ENergy Antiproton decelerator (ELENA) project is under way since 2011. In the past 3 years, it has considerably evolved into a detailed design for the ring and the transfer lines. It is a small machine, ~30 m in circumference, with a rather tight specification for the average pressure seen by the anti-proton beams injected by the anti-proton decelerator (AD). The average pressure in ELENA must be limited to 4x10^-12 mbar (H2-equivalent) in order to limit the charge-exchange losses during the rather long deceleration process (several tens of seconds), during which the energy of the beam is reduced and the electron-cooler is used twice in order to decrease the transverse emittance of the anti-proton beam. This paper will discuss the design of the chambers of the injection line, extraction line and the ring. It will also mention the actual status of the vacuum system for the transfer lines to the experiments, LNE, which are under finalisation. The results of detailed 3D simulations made with the test-particle montecarlo code Molflow+ will be discussed, alongside with the choice for the pumping system, mainly distributed NEG-coatings and integrated NEG/ion-pumps.

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WEPHA022

Characterization of Nb Coating in HIE-ISOLDE QWR Superconducting Accelerating Cavities by means of SEM-FIB and TEM

cavity, interface, electron, niobium

3155

B. Bártová, S. Calatroni, A. Sublet, M. Taborelli
CERN, Geneva, Switzerland
A.B. Aebersold, D.T.L. Alexander, M. Cantoni
EPFL, Lausanne, Switzerland

The Quarter Wave Resonators (QWR) high-β cavities (0.3m diameter and 0.9m height) are made from OFE 3D-forged copper and are coated by DC-bias diode sputtering with a thin superconducting layer of niobium. The Nb film thickness, morphology, purity and quality are critical parameters for RF performances of the cavity. They have been investigated in a detailed material study. The coating structure at different positions along a test cavity was observed by cross-section imaging using SEM-FIB instrument. The samples from the top of the cavity showed presence of unexpected porosities, whose volume was investigated using FIB tomography. TEM lamella was prepared for two samples (top part and inner conductor of the cavity) to study in detail the grain orientation in the coating, its chemical composition and structure. The 14-layer structure in thick coating was indeed evidenced by the TEM analysis. Chemical mapping revealed the presence of a few nm in size copper precipitates close to the Nb/Cu interface and a passivating oxide layer of 10 nm thickness on top of the coating and around porosities. However no impurities or interface layer along the coating profile were present.

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WEPHA046

Outgassing Analysis During Transport for 14m Long Arc-Cell Vacuum Chambers of the Taiwan Photon Source

vacuum, photon, storage-ring, electron

3219

L.H. Wu, C.K. Chan, C.H. Chang, C.-C. Chang, S.W. Chang, Y.P. Chang, B.Y. Chen, J.-R. Chen, Z.W. Chen, C.M. Cheng, G.-Y. Hsiung, S-N. Hsu, H.P. Hsueh, C.S. Huang, Y.T. Huang, T.Y. Lee, I.C. Yang
NSRRC, Hsinchu, Taiwan
J.-R. Chen
National Tsing Hua University, Hsinchu, Taiwan

An outgassing analysis during transportation for the large, 14-m-long, ultra-high-vacuum aluminum arc-cell chambers of the Taiwan Photon Source (TPS) was performed using residual gas analysis (RGA). Each cell was baked to 150 °C in the laboratory to achieve ultra-high vacuum. Under pumping by primarily ion pumps (IP) and non-evaporable getter (NEG) pumps, the cells obtained pressures of 6.4×10^-9 Pa on average, and the main residual gas was H2. Here, vacuum pressure measurements and residual gas analyses were performed in situ while a cell chamber was being transported. It was found that the vibration of the arc-cell vacuum chamber caused the pressure to rise abruptly; in this case, the main outgassing gas was CH4. Once the arc cell had been fully installed, the vacuum pressure gradually decreased to the original vacuum pressure because of the pumping effect of the ion gauges.

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WEPTY028

Fermilab Linac Laser Notcher

laser, linac, booster, cavity

3328

D.E. Johnson, K.L. Duel, M.H. Gardner, T.R. Johnson, V.E. Scarpine, R. Tesarek
Fermilab, Batavia, Illinois, USA

Synchrotrons or storage rings require a small section of their circumference devoid of any beam (i.e. a “notch”) to allow for the rise time of an extraction kicker device. In multi-turn injection schemes, this notch in the beam may be generated either in the linac pulse prior to injection or in the accelerator itself after injection. In the case of the Fermilab Booster, the notch is created in the ring near injection energy by the use of fast kickers, thus depositing the beam in a shielded collimation region within the accelerator tunnel. With increasing beam powers, it is desirable to create this notch at the lowest possible energy to minimize activation. Fermilab has undertaken an R&D project to build a laser system to create the notch within a linac beam pulse, immediately after the RFQ at 750 keV, where activation issues are negligible. We will describe the concept for the laser notcher and discuss our current status and future plans for installation of the device.

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WEPTY048

An RFQ Direct Injection Scheme for the IsoDAR High Intensity H²⁺ Cyclotron

rfq, cyclotron, injection, ion-source

3384

D. Winklehner, J.R. Alonso, J.M. Conrad
MIT, Cambridge, Massachusetts, USA
R.W. Hamm
R&M Technical Enterprises, Pleasanton, California, USA

IsoDAR is a novel experiment designed to measure neutrino oscillations through electron-antineutrino disappearance, thus providing a definitive search for sterile neutrinos. In order to generate the necessary anti-neutrino flux, a high intensity primary proton beam is needed. In IsoDAR, H²⁺ is accelerated, and is stripped into protons just before the target, to overcome space charge issues at injection. As part of the design, we have refined an old proposal to use an RFQ to axially inject bunched H²⁺ ions into the driver cyclotron. This method has several advantages over a classical low energy beam transport (LEBT) design: (1) The bunching efficiency is higher than for the previously considered two-gap buncher and thus the overall injection efficiency is higher. This relaxes the constraints on the H²⁺ current required from the ion source. (2) The overall length of the LEBT can be reduced. (3) The RFQ can also accelerate the ions. This enables the ion source platform high voltage to be reduced from 70 kV to 30 kV, making underground installation easier. We will present preliminary RFQ design parameters and first beam dynamics simulations from the ion source to the spiral inflector.

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WEPTY061

Progress on the Cryogenic and Current Tests of the MSU Cyclotron Gas Stopper Superconducting Magnet

cyclotron, cryogenics, vacuum, dipole

3415

M.A. Green, G. Bollen, S. Chouhan, A.F. Zeller
FRIB, East Lansing, Michigan, USA
J. DeKamp, C. Magsig, D.J. Morrissey, J. Ottarson, S. Schwarz
NSCL, East Lansing, Michigan, USA

Funding: This work reported in this paper was supported in part by an NSF grant PHY-0958726
The Michigan State University (MSU) cyclotron gas stopper magnet is a warm iron superconducting cyclotron dipole. The desired field shape is obtained by the pole iron profile. Each coil of the two halves is in a separate cryostat and connected in series through a warm electrical connection. The entire system is mounted on a high voltage platform, and is cooled using six two-stage 4.2 K pulse tube coolers. This paper presents the progress on the magnet fabrication, cooling, and current testing.

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WEPWI012

First Attempt of At-cavity X-ray Detection in a CEBAF Cryomodule for Field Emission Monitoring

cavity, cryomodule, cryogenics, electron

3515

R.L. Geng, E. Daly, M.A. Drury, A.D. Palczewski
JLab, Newport News, Virginia, USA

We report on the first result of at-cavity X-ray detection in a CEBAF cryomodule for field emission monitoring. In the 8-cavity cryomodule F100, two silicon diodes were installed near the end flange of each cavity. Each cavity was individually tested during the cryomodule test in JLab’s cryomodule test facility. The behaviors of these at-cavity cryogenic X-ray detectors were compared with those of the standard “in air” Geiger-Muller tubes. Our initial experiments establish correlation between X-ray response of near diodes and the field emission source cavity in the 8-cavity string. For two out of these eight cavities, we also carried out at-cavity X-ray detection experiment during their vertical testing. The aim is to track field emission behavior uniquely from vertical cavity testing to horizontal cavity testing in the cryomodule.

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WEPWI022

RF System Requirements for a Medium-Energy Electron-Ion Collider (MEIC) at JLab

electron, collider, booster, SRF

3536

R.A. Rimmer, J. Guo, J. Henry, H. Wang, S. Wang
JLab, Newport News, Virginia, USA
Y.L. Huang
IMP/CAS, Lanzhou, People's Republic of China

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
JLab is studying options for a medium energy electron-ion collider that could fit on the JLab site and use CEBAF as a full-energy electron injector. A new ion source, linac and booster would be required, together with collider storage rings for the ions and electrons. In order to achieve the maximum luminosity these will be high current storage rings with many bunches. We present the high level RF system requirements for the storage rings, ion booster ring and high-energy ion beam cooling system, and describe the technology options under consideration to meet them. We also present options for staging that might reduce the initial capital cost while providing a smooth upgrade path to a higher final energy. The technologies under consideration may also be useful for other proposed storage ring colliders or ultimate light sources.

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WEPWI024

Vacuum Characterization and Improvement for the Jefferson Lab Polarized Electron Source

electron, vacuum, background, gun

3540

M.L. Stutzman, P.A. Adderley, M. Poelker
JLab, Newport News, Virginia, USA
M.A. Mamun
Old Dominion University, Norfolk, Virginia, USA

Operating the JLab polarized electron source with high reliability and long lifetime requires vacuum near the XHV level (<=1x10^-12 Torr). This paper describes ongoing vacuum research at Jefferson Lab including characterization of outgassing rates for surface coatings and heat treatments, ultimate pressure measurements, investigation of pumping including an XHV cryopump, and characterization of ionization gauges in this pressure regime.

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WEPWI040

Experiment and Results on Plasma Etching of SRF Cavities

cavity, plasma, SRF, niobium

3581

J. Upadhyay, J.J. Peshl, S. Popović, L. Vušković
ODU, Norfolk, Virginia, USA
D.S. Im
Old Dominion University, Norfolk, Virginia, USA
H.L. Phillips, A-M. Valente-Feliciano
JLab, Newport News, Virginia, USA

The inner surfaces of SRF cavities are currently chemically treated (etched or electro polished) to achieve the state of the art RF performance. We designed an apparatus and developed a method for plasma etching of the inner surface for SRF cavities. The process parameters (pressure, power, gas concentration, diameter and shape of the inner electrode, temperature and positive dc bias at inner electrode) are optimized for cylindrical geometry. The etch rate non-uniformity has been overcome by simultaneous translation of the gas point-of-entry and the inner electrode during the processing. A single cell SRF cavity has been centrifugally barrel polished, chemically etched and RF tested to establish a baseline performance. This cavity is plasma etched and RF tested afterwards. The effect of plasma etching on the RF performance of this cavity will be presented and discussed.

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THXC2

Ion Beam Therapy with Ions Heavier than Protons: Performance and Prospects

proton, neutron, radiation, shielding

3654

U. Linz
FZJ, Jülich, Germany

Starting from a short discussion on the pros and cons of heavier ions for therapy, the presentation will concentrate on two aspects of the therapy with ions heavier than protons: technical equipment and choice of ion. As major components of an IBT facility, accelerator and gantry issues will dominate the part on equipment. Biophysical, medical, and economical considerations will be discussed in the part featuring the choice of the proper ion.

Slides THXC2 [10.744 MB]

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THPF003

BEST 70P Cyclotron Factory Test

ion-source, cyclotron, injection, emittance

3680

V. Sabaiduc, T. Boiesan, M. Carlson, D. Du, F.S. Grillet, R.R. Johnson, F.S. Labrecque, B.F. Milton, L. AC. Piazza, R. Ruegg, V. Ryjkov, W. Stazyk, K. Suthanthiran, S. Talmor, B.A. Versteeg, J. Zhu
BCSI, Vancouver, BC, Canada
T. Evans, J. Harris, N. Matte, J. Panama, P. Zanetti
Best Theratronics Ltd., Ottawa, Ontario, Canada

Best Cyclotron Systems Inc (BCSI) designed and manufactured a 70MeV compact cyclotron for radioisotope production and research applications. The cyclotron undergone exhaustive factory testing that has been successfully completed at Best Theratronics facility in Ottawa, Canada. The first 70MeV cyclotron has been build for the INFN-LNL laboratory in Legnaro, Italy. The cyclotron has external negative hydrogen ion source, four radial sectors with two dees in opposite valleys, cryogenic vacuum system and simultaneous beam extraction on opposite lines. The beam intensity is 700μA with variable extraction energy between 35 and 70MeV. We are reporting the factory acceptance testing results confirming the individual cyclotron systems performance and beam acceleration to 1MeV probe. Detail measurements of each system stability and performance have been taken as well as full characterisation of beam acceleration through the injection line and on to the 1MeV probe. The BEST70p cyclotron may also be used as injector to a post-accelerator or for the production of the radioactive beams.

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THPF007

Optimization of Multi-turn Injection into a Heavy-Ion Synchrotron using Genetic Algorithms

injection, space-charge, emittance, linac

3689

S. Appel, O. Boine-Frankenheim
GSI, Darmstadt, Germany
O. Boine-Frankenheim
TEMF, TU Darmstadt, Darmstadt, Germany

For heavy-ion synchrotrons an efficient multi-turn injection (MTI) from the injector linac is crucial in order to reach the specified currents using the available machine acceptance. The beam loss during the MTI must not exceed the limits determined by machine protection and vacuum requirements. Especially for low energy and intermediate charge state ions, the beam loss can cause a degradation of the vacuum and a corresponding reduction of the beam lifetime. In order to optimize the MTI a genetic algorithm based optimization is used to simultaneously minimize the loss and maximize the multiplication factor (e.g. stored currents in the synchrotron). The effect of transverse space charge force on the MTI has also been taken into account. The optimization resulted in injection parameters, which promise a significant improvement of the MTI performance for intense beams in the SIS18 synchrotron at GSI.

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THPF008

U²⁸⁺ Intensity Record Applying a H2-Gas Stripper Cell

operation, target, heavy-ion, acceleration

3693

W.A. Barth, A. Adonin, Ch.E. Düllmann, M. Heilmann, R. Hollinger, E. Jäger, J. Khuyagbaatar, J. Krier, H. Vormann, A. Yakushev
GSI, Darmstadt, Germany
P. Scharrer
HIM, Mainz, Germany

Meeting the FAIR science requirements higher beam intensity has to be achieved in the present GSI-accelerator complex. An advanced upgrade program for the UNILAC aimed to meet the FAIR requirements. Stripping is a key technology for all heavy ion accelerators. For this an extensive research and development program was carried out to optimize for high brilliance heavy ion operation. After upgrade of the supersonic N2-gas jet, implementation of high current foil stripping and preliminary investigation of H2 gas jet operation, recently a newly developed H2 gas cell uses a pulsed gas regime synchronized with arrival of the beam pulse. An obviously enhanced stripper gas density as well as a simultaneously reduced gas load for the pumping system result in an increased stripping efficiency, while the beam emittance remains the same. A new record intensity (7.8 emA) for U²⁸⁺ beams at 1.4 MeV/u has been achieved applying the pulsed high density H2 stripper target, while the MeVVa ion source with a newly developed extraction system delivered a high intensity U⁴⁺ beam. The experimental results will be presented in detail.

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THPF010

Simulation and Experimental Investigation of Heavy Ion Induced Desorption from Cryogenic Targets

target, cryogenics, simulation, experiment

3699

Ch. Maurer, D.H.H. Hoffmann
TU Darmstadt, Darmstadt, Germany
L.H.J. Bozyk, H. Kollmus, Ch. Maurer, P.J. Spiller
GSI, Darmstadt, Germany

Funding: Bundesministerium für Bildung und Forschung FKZ 06DA7031
Heavy-ion impact induced gas desorption is the key process that drives beam intensity limiting dynamic vacuum losses. Minimizing this effect, by providing low desorption yield surfaces, is an important issue for maintaining a stable ultra high vacuum during operation with medium charge state heavy ions. For room temperature targets, investigation shows a scaling of the desorption yield with the beam's near-surface electronic energy loss, i.e. a decrease with increasing energy*,**. An optimized material for a room temperature ion-catcher has been found. But for the planned superconducting heavy-ion synchrotron SIS100 at the FAIR accelerator complex, the ion catcher system has to work in a cryogenic environment. Desorption measurements with the prototype cryocatcher for SIS100 showed an unexpected energy scaling***, which needs to be explained. Understanding this scaling might lead to a better suited choice of material, resulting in a lower desorption yield. Here, new experimental results will be presented along with insights gained from gas dynamics simulations.
* H. Kollmus et al., AIP Conf. Proc. 773, 207 (2005))
** E. Mahner et al., Phys. Rev. ST Accel. Beams 14, 050102 (2011)
*** L.H.J. Bozyk, H. Kollmus, P.J. Spiller, Proc. of IPAC 2012, p. 3239

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THPF013

UNILAC Proton Injector Operation for FAIR

proton, cavity, linac, operation

3709

M. Heilmann, A. Adonin, S. Appel, W.A. Barth, P. Gerhard, F. Heymach, R. Hollinger, W. Vinzenz, H. Vormann, S. Yaramyshev
GSI, Darmstadt, Germany
W.A. Barth
HIM, Mainz, Germany

The pbar physics program at the Facility for Antiproton and Ion Research (FAIR) requires a high number of cooled pbars per hour. The FAIR proton injector with coupled CH-cavities will provide for a high intensity (35 mA) pulsed 70 MeV proton beam at a repetition rate of 4 Hz. The recent heavy ion UNIversal Linear Accelerator (UNILAC) at GSI is able to deliver proton as well as heavy ion beams for injection into the FAIR-synchrotrons. Recently GSI UNILAC could provide for a two orders of magnitude higher proton beam current in routine operation. A hydrocarbon beam (CH3) from the MUCIS ion source was accelerated inside High Current Injector and cracked in a supersonic nitrogen gas jet into stripped protons and carbon ions. A new proton beam intensities record (3 mA) could be achieved during machine experiments in October 2014. Potentially up to 25% of the FAIR proton beam performance is achievable at a maximum UNILAC beam energy of 20 MeV and a repetition rate of 4 Hz. The UNILAC can be used as a high performance proton injector for initial FAIR-commissioning and as a redundant option for the first FAIR-experiments.

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THPF015

Status of the FAIR Heavy Ion Synchrotron Project SIS100

quadrupole, dipole, cryogenics, injection

3715

P.J. Spiller, U. Blell, L.H.J. Bozyk, J. Ceballos Velasco, T. Eisel, E.S. Fischer, O.K. Kester, H.G. König, H. Kollmus, V. Kornilov, P. Kowina, J.P. Meier, A. Mierau, C. Mühle, C. Omet, D. Ondreka, N. Pyka, H.R. Ramakers, P. Rottländer, C. Roux, P. Schnizer, St. Wilfert
GSI, Darmstadt, Germany

The procurements of major technical components for the heavy ion synchrotron SIS100 are progressing. Especially the production of the long lead items, the main superconducting dipole and quadrupole magnets and the main Rf systems could be started. The system layout for the injection system and the specifications for all injection devices has been completed. In parallel, the Digital Mock-Up (DMU) and design for major extraction components has been developed. Certain technical challenges observed during the acceptance tests of First of Series (FOS) components and risks and their mitigation will be presented.

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THPF018

Simulation Studies of Plasma-based Charge Strippers

target, plasma, electron, heavy-ion

3721

O.S. Haas
TEMF, TU Darmstadt, Darmstadt, Germany

Calculations on the charge state distributions in different charge stripping media are presented. The main focus of this work is the width and peak efficiency of the final charge state distribution. For equal number densities fully-stripped plasma stripping media achieve much higher charge states than gas stripping media of the same nuclear charge. This is due to the reduced electron capture rates of free target electrons compared to bound target electrons. Furthermore, targets with low nuclear charge like hydrogen achieve higher charge states than targets with high nuclear charge like nitrogen in the case of both a plasma and a gas target. Equal final mean charge states can thus be achieved with lower density for plasmas and targets with low nuclear charge. The widths of the charge state distributions are very similar, slightly smaller for plasmas due to the different scaling of the dielectronic recombination rate. In comparison with calculations and measurements published in literature this work underestimates the width of targets with higher nuclear charge like, e.g., nitrogen gas. This is mainly due to the omission of multiple loss processes in the presented calculations. In the future we intend to expand the methods and models used in this work to improve the agreement with different measurements on charge state distributions in plasmas and gases.

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THPF019

Status and First Measurement Results for a High Gradient CH-Cavity

cavity, linac, resonance, operation

3724

A. Almomani, U. Ratzinger
IAP, Frankfurt am Main, Germany

Funding: BMBF, contract no. 05P12RFRB9
This pulsed linac activity aims on compact designs and on a considerable increase of the voltage gain per meter. A high gradient CH-cavity operated at 325 MHz was developed at IAP-Frankfurt. The mean effective accelerating field for this cavity is expected well above 10 MV/m at β = 0.164. This cavity is developed within a funded project. The results might influence the rebuilt of the UNILAC-Alvarez section, aiming to achieve the beam intensities specified for the GSI - FAIR project (15 mA U²⁸⁺). Another motivation is the development of an efficient pulsed ion accelerator for significantly higher energies like 60 AMeV. The new GSI 3 MW Thales klystron test stand will be used for the cavity RF power tests. Detailed studies on two different types of copper plating will be performed with this cavity.

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THPF024

LEBT Dynamics and RFQ Injection

solenoid, rfq, injection, collimation

3739

P.P. Schneider, M. Droba, O. Meusel, H. Niebuhr, D. Noll, O. Payir, H. Podlech, A. Schempp, C. Wiesner
IAP, Frankfurt am Main, Germany

The Low Energy Beam Transport (LEBT) section at the accelerator-driven neutron source FRANZ* consists of four solenoids, two of which match the primary proton beam into the chopper. The remaining two solenoids are intended to prepare the beam for injection into the RFQ. In the first commissioning phase, the LEBT successfully transported a 14 keV He beam at low intensities**. In the current commissioning phase, the beam energy is increased to the RFQ injection energy of 120 keV. In the upcoming step, the intensity will be increased from 2 mA to 50 mA. Beam dynamics calculations include effects of different source emittances, position and angle offsets and the effects of space charge compensation levels. In addition, the behavior of the undesired hydrogen fractions, H²⁺ and H³⁺, and their influence on the performance within the RFQ is simulated.
* Meusel, O., et al. "FRANZ–Accelerator Test Bench And Neutron Source", MO3A03, LINAC 2012.
** Wiesner, C., et al. "Chopping High-Intensity Ion Beams at FRANZ", WEIOB01, LINAC 2014.

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THPF025

Beam Dynamics for the SC CW Heavy Ion LINAC at GSI

linac, cavity, heavy-ion, emittance

3742

M. Schwarz, M. Amberg, M. Basten, F.D. Dziuba, H. Podlech, U. Ratzinger, R. Tiede
IAP, Frankfurt am Main, Germany
M. Amberg, K. Aulenbacher, M. Miski-Oglu
HIM, Mainz, Germany
W.A. Barth, V. Gettmann, M. Heilmann, S. Mickat, A. Orzhekhovskaya, S. Yaramyshev
GSI, Darmstadt, Germany

Funding: Work supported by BMBF contr. No. 05P12RFRBL
For future experiments with heavy ions near the coulomb barrier within the SHE (super-heavy elements) research project a multi-stage R&D program of GSI, HIM and IAP is currently in progress*. It aims at developing a superconducting (sc) continuous wave (cw) LINAC with multiple CH cavities as key components downstream the High Charge Injector (HLI) at GSI. The beam dynamics concept is based on EQUUS (equidistant multigap structure) constant-beta cavities. Advantages of its periodicity are a high simulation accuracy, easy manufacturing and tuning with minimized costs as well as a straightforward energy variation. The next milestone will be a full performance beam test of the first LINAC section, comprising two solenoids and a 15-gap CH cavity inside a cryostat (Demonstrator).
*W. Barth et al., ‘‘Further R&D for a new Superconducting cw Heavy Ion LINAC@GSI'', THPME004, IPAC'14, Dresden, Germany (2014)

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THPF027

Ten Gap Model of a New Alvarez DTL Cavity at GSI

simulation, cavity, DTL, impedance

3748

A. Seibel, O.K. Kester
IAP, Frankfurt am Main, Germany
X. Du, L. Groening, S. Mickat
GSI, Darmstadt, Germany

In order to meet the challenges of the FAIR project at GSI requiring highest beam intensities an upgrade of the existing Universal Linear Accelerator (UNILAC) is planned. The 10⁸ MHz cavities will be replaced by new rf-structures of the same frequency. Simulations are done to improve the rf-properties. The geometry of the drift tubes is to be changed to a smoother curvature to reach a homogeneous surface field distribution and higher shunt impedances. To check the necessity of cooling channels, simulations on the temperature distribution at the drift tubes and stems are conducted. A test bench for low power rf-measurements with a 10 gap aluminum model (scale 1:3) is under construction. The modular mechanical design of the model will allow probing experimentally a wide range of drift tube and stem geometries. With the bead pull method the electrical field distribution will be measured as well as the field stability with respect to parasitic modes. Additionally, appropriate locations along the cavity to place fixed and dynamic rf-frequency tuners will be determined.

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THPF028

Conceptual Design of a Novel RFQ for Medical Accelerators

rfq, simulation, alignment, ion-source

3751

R. Cee, E. Feldmeier, Th. Haberer, A. Peters, T.W. Winkelmann
HIT, Heidelberg, Germany

At the Heidelberg Ion Beam Therapy Centre HIT we operate a 4-rod RFQ as first stage of a 7 MeV/u injector linac followed by an IH-DTL. During the first years of patient treatment the injector performance was perfectly adequate, even though the transmission of the linac remained below the theoretical expectations. New developments in dose delivery technology already realised or to come in the future increase the demand on higher beam intensities which will finally result in shorter irradiation times. As measurements performed at our test bench have confirmed that there is a margin for higher transmissions especially for the RFQ we are currently preparing for a new RFQ design. While keeping the original design parameters, the new RFQ should be optimised with respect to the transmission of beams from different ion sources such as electron cyclotron resonance or electron beam ion sources. All parts of the RFQ will be put up for discussion including electrodes, stems, tank and the integrated rebuncher. The design work will profit from new concepts that have evolved at our own and other medical heavy ion facilities in operation and from the progress modern simulation tools have run through.

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THPF029

Preparation of an Ion Source for an Extra Low Energy Synchrotron

extraction, ion-source, antiproton, electron

3755

R. Gebel, O. Felden, R. Maier, S. Mey, D. Prasuhn
FZJ, Jülich, Germany

Funding: The work is supported within the framework of the Helmholtz Association’s Accelerator Research and Development (ARD) program.
ELENA* is a compact ring for cooling and further deceleration of 5.3 MeV antiprotons delivered by the CERN Antiproton Decelerator (AD) down to 100 keV. Because of the long AD cycle of 100 s, it is foreseen to use a source for protons and H⁻ with a kinetic energy of 100 keV for commissioning and start-ups. The source, designed to provide 0.2 to 2.0μsec pulses with 3x10⁷ ions, is based on a proven multicusp volume source used at the COSY/Jülich** injector cyclotron. The source and its auxiliaries were refurbished, upgraded to ±100 keV operation at the Forschungszentrum Jülich and have been set in operation at CERN in April 2015 for first tests of new equipments.
* V. Chohan [ed.], ELENA ring and its Transfer Lines – Design Report
Geneva 2014, DOI 10.5170/CERN-2014-002
** R. Maier Nucl. Instr. Meth. A 390 (1997) P.1.

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THPF035

Stripping of High Intensity Heavy-Ion Beams in a Pulsed Gas Stripper Device at 1.4 MeV/u

brilliance, emittance, dipole, acceleration

3773

P. Scharrer, W.A. Barth, Ch.E. Düllmann, J. Khuyagbaatar
HIM, Mainz, Germany
W.A. Barth, M. Bevcic, Ch.E. Düllmann, L. Groening, K.P. Horn, E. Jäger, J. Khuyagbaatar, J. Krier, A. Yakushev
GSI, Darmstadt, Germany
Ch.E. Düllmann
Mainz University, Mainz, Germany

As part of an injector system for FAIR, the GSI UNILAC has to meet high demands in terms of beam brilliance at a low duty factor. To accomplish this goal an extensive upgrade program has started. To increase the beam intensity behind the UNILAC, it is aimed to increase the efficiency of the 1.4 MeV/u gas stripper. A modification of the stripper setup was developed to replace the N2-jet with a pulsed gas injection, synchronized with the transit of the beam pulse. The pulsed gas injection lowers the gas load for the differential pumping system, rendering possible the use of other promising gas targets. In recent measurements the performance of the modified setup was tested using an 238U-beam with various stripper media, including H2, He, and N2. The data provide a systematic basis for an improved understanding of slow heavy ions passing through gaseous media. The stripping performance of the current N2-jet was excelled by using H2 at increased gas densities, enabled by the new pulsed gas cell.

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THPF036

Compact Cyclotron for 35 MeV Protons and 8 AMeV of H²⁺

cyclotron, proton, extraction, acceleration

3776

A. Calanna, L. Calabretta
INFN/LNS, Catania, Italy
T. Boiesan, R.R. Johnson, L. AC. Piazza, V. Sabaiduc
BCSI, Vancouver, BC, Canada

The design characteristics and parameters of a compact cyclotron able to accelerate H⁻ ions up to an energy of 35 MeV and H²⁺ ions up to an energy of 8 AMeV are presented. This cyclotron is a 4 sector machine and its special feature is the possibility to modify the profiles of the sector hills to allow for the acceleration of the two different species. When equipped with two RF cavities and operated in harmonic mode 4, it accelerates the H⁻ beam, which is extracted by stripping. The resulting proton beam is used for the commercial goal of radioisotope production. On the other hand, when equipped with four RF cavities, also operated in harmonic mode 4, it accelerates a high intensity H²⁺ beam that is of interest for the IsoDAR* experiment. Here, the presented cyclotron takes on the role of a prototype for the central region design of the final IsoDAR* cyclotron (60 A MeV H²⁺). By increasing the number of cavities, the energy gain per turn as well as the vertical focusing along the first orbit are increased, thereby optimizing the acceptance. Moreover, to minimize space-charge effects, the injection energy of H²⁺ is raised to 70 keV compared to the H⁻ injection energy of 40 keV.
arXiv:1307.2949 Whitepaper on the DAEδALUS Program. The DAEδALUS Collaboration

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THPF037

Upgrade of the LNS Superconducting Cyclotron

extraction, cyclotron, experiment, closed-orbit

3779

A. Calanna, L. Calabretta, G. Cuttone, G. Dagostino, D. Rifuggiato
INFN/LNS, Catania, Italy
M. Maggiore
INFN/LNL, Legnaro (PD), Italy
A. Radovinsky
MIT/PSFC, Cambridge, Massachusetts, USA

The superconducting cyclotron of the LNS-INFN has been working for about 20 years delivering ion beams from proton to gold in the wide energy range from 15 AMeV to 80 AMeV. The beam extraction is performed by means of two electrostatic deflectors and a set of magnetic channels. Recently, the experiment NUMEN has been proposed to study the nuclear matrix element for the double beta decay . The requirements on target are light ion beams (A<30), with an energy range of 15-60 AMeV and a beam power of 1-5 kW. To achieve this goal we have studied the feasibility of extraction by stripping through the existing extraction channel with an increased transversal section. In addition, a new extraction channel has been designed to increase as much as possible the number of the extracted ions and energies. To allow the realization of these new channels, a new superconducting magnet is needed. The major changes and the expected performances for the upgraded cyclotron, as well as the state-of-art of the design, are here presented.

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THPF038

RIB Transport and Selection for the SPES Project

rfq, emittance, simulation, target

3782

M. Comunian, L. Bellan, A. Pisent
INFN/LNL, Legnaro (PD), Italy
A.D. Russo
INFN/LNS, Catania, Italy

The SPES project, at Legnaro National Laboratories (LNL) in Italy, is a RIB ISOL facility for the production and acceleration of “neutron-rich” radioactive ion beams. The beam dynamics of the re-accelerator part is presented with the focus on the preselection and transfer to the charge breeder device and from this device to the CW RFQ used as injector to the LNL linac ALPI.

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THPF046

Operation of the RHIC Injector Chain with Ions from EBIS

booster, emittance, injection, extraction

3804

C.J. Gardner, J.G. Alessi, E.N. Beebe, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, J.J. Butler, C. Carlson, W. Fischer, D.M. Gassner, D. Goldberg, T. Hayes, H. Huang, P.F. Ingrassia, J.P. Jamilkowski, N.A. Kling, J.S. Laster, D. Maffei, M. Mapes, I. Marneris, G.J. Marr, A. Marusic, D.R. McCafferty, K. Mernick, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, S. Perez, A.I. Pikin, D. Raparia, T. Roser, P. Sampson, J. Sandberg, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, P. Thieberger, J.E. Tuozzolo, B. Van Kuik, A. Zaltsman, K. Zeno, W. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Since 2012 gold and all other ions for the RHIC injector chain have been provided by an Electron Beam Ion Source (EBIS). The source is followed by an RFQ, a short Linac, and a 30 m transport line. These components replace the Tandem van de Graaff and associated 840 m transfer line. They provide ions at 2 MeV per nucleon (kinetic energy) for injection into the AGS Booster. The setup and operation of Booster and AGS with various ions from the new source are reviewed.

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THPF059

RHIC Electron Lenses Upgrades

electron, proton, cathode, controls

3830

X. Gu, Z. Altinbas, S. Binello, D. Bruno, M.R. Costanzo, K.A. Drees, W. Fischer, D.M. Gassner, M. Harvey, J. Hock, K. Hock, Y. Luo, A. Marusic, K. Mernick, C. Mi, R.J. Michnoff, T.A. Miller, M.G. Minty, A.I. Pikin, G. Robert-Demolaize, T. Samms, V. Schoefer, T.C. Shrey, Y. Tan, R. Than, P. Thieberger
BNL, Upton, Long Island, New York, USA
S.M. White
ESRF, Grenoble, France

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In the Relativistic Heavy Ion Collider (RHIC) 100 GeV polarized proton run in 2015[1], two electron lenses [2] were used for the first time to partially compensate for the head-on beam-beam effect. Here, we describe the design of the current electron lens, detailing the hardware modifications made after the 2014 commissioning run with heavy ions. A new electron gun with 15-mm diameter cathode is characterized. The electron beam transverse profile was measured using a YAG screen and fitted with a Gaussian distribution. During operation, the overlap of the electron and proton beams was achieved using the electron backscattering detector in conjunction with an automated orbit control program.

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THPF070

Prototyping Progress of SSR1 Single Spoke Resonator for RAON

cavity, target, simulation, vacuum

3842

H.J. Cha, H. Kim, H.J. Kim, W.K. Kim, G.-T. Park
IBS, Daejeon, Republic of Korea

The fabrication of prototypes for four different types of superconducting cavities (QWR, HWR, SSR1, and SSR2) for the Korean heavy ion accelerator, “RAON” is in progress. In this presentation, we report the current status of the SSR1 cavity (β=0.3 and f=325 MHz) prototype fabrication based on the technical designs. The simulation results on the target frequency determination for the clamp-up test of the prototype are also given.

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THPF073

Progress of the RAON Heavy Ion Accelerator Project

cryomodule, ECR, rfq, ion-source

3848

D. Jeon
IBS, Daejeon, Republic of Korea

Construction of the RAON heavy ion accelerator facility is under way in Korea that includes both the In-flight Fragment (IF) and Isotope Separation On-Line (ISOL) facilities to support cutting-edge researches in various science fields. Prototyping and testing of major components are proceeding including 28 GHz ECR ion source, RFQ, superconducting cavities, cryomodules, superconducting magnets. Superconducting magnets of 28 GHz ECR ion source are fabricated and tested. First article of prototype superconducting cavities are delivered that were fabricated through domestic vendors and tested at TRIUMF. Prototype HTS(High Tc Superconducting) magnets is in progress. Progress report of the RAON accelerator systems is presented.

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THPF074

Progress on Superconducting Linac for the RAON Heavy Ion Accelerator

cavity, linac, cryomodule, electron

3851

H.J. Kim, H.C. Jung, W.K. Kim
IBS, Daejeon, Republic of Korea

The RISP (Rare Isotope Science Project) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. It can deliver ions from proton to Uranium. Proton and Uranium beams are accelerated upto 600 MeV and 200 MeV/u respectively. The facility consists of three superconducting linacs of which superconducting cavities are independently phased. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the RISP linac design, the prototyping of superconducting cavity and cryomodule.

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THPF075

Proton Beam of 2 MeV 1.6 mA on a Tandem Accelerator with Vacuum Insulation

neutron, vacuum, proton, high-voltage

3854

S.Yu. Taskaev, D.A. Kasatov, A.S. Kuznetsov, A.N. Makarov, I.M. Shchudlo, I.N. Sorokin
BINP SB RAS, Novosibirsk, Russia

Funding: The research is conducted with the financial support of the Ministry of Education and Science of the Russian Federation (a unique identifier for applied scientific research – RFMEFI60414X0066).
New type of charged particles accelerator, tandem accelerator with vacuum insulation, was proposed in BINP. The accelerator is characterized by fast acceleration of charged particles, long distance between ion beam and insulator (on which electrodes are mounted), big stored energy in the accelerating gaps and strong input electrostatic lens. High-voltage strength of vacuum gaps, dark currents, ion beam focusing, accelerating and stripping were investigated. Stationary proton beam with 2 MeV energy, 1.6 mA current has just been obtained. The beam is characterized by high energy monochromaticity – 0.1%, and high current stability – 0.5%. Here we report the results of these investigations and discuss the proposal for obtaining 2.5 MeV 3 mA proton beam. The accelerator is considered to be a part of epithermal neutron source for boron neutron capture therapy and monoenergetic neutron source for calibration of dark matter detector.

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THPF093

Status of the LHC Injectors Upgrade (LIU) Project at CERN

brightness, proton, linac, injection

3915

M. Meddahi, J. Coupard, H. Damerau, A. Funken, S.S. Gilardoni, B. Goddard, K. Hanke, L. Kobzeva, A.M. Lombardi, D. Manglunki, S. Mataguez, B. Mikulec, G. Rumolo, E.N. Shaposhnikova, M. Vretenar
CERN, Geneva, Switzerland

CERN is currently carrying out an ambitious improvement programme of the full LHC Injectors chain in order to enable the delivery of beams with the challenging HL-LHC parameters. The LHC Injectors Upgrade project coordinates this massive upgrade program, and covers a new linac (Linac4 project) as well as upgrades to the Proton Synchrotron Booster, the Proton Synchrotron and Super Proton Synchrotron. The heavy ion injector chain is also included, adding the Linac3 and Low Energy Ion Ring to the list of accelerators concerned. The performance objectives and roadmap of the main upgrades will be presented, including the work status and outlook. The machine studies and milestones during LHC Run 2 will be discussed and a preliminary Long Shutdown 2 installation planning given. Finally, for the LHC Run 3, the beam performance across the full injector chain after all the upgrades will be estimated and the required commissioning stages outlined.

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THPF099

Upgrade of the SPS Ion Injection System

injection, emittance, kicker, simulation

3938

J.A. Uythoven, J. Borburgh, E. Bravin, S. Burger, E. Carlier, J.-M. Cravero, L. Ducimetière, S.S. Gilardoni, B. Goddard, J. Hansen, E.B. Holzer, M. Hourican, T. Kramer, F.L. Maciariello, D. Manglunki, F.-X. Nuiry, A. Perillo Marcone, G.E. Steele, F.M. Velotti, H. Vincke
CERN, Geneva, Switzerland

As part of the LHC Injectors Upgrade Project (LIU) the injection system into the SPS will be upgraded for the use with ions. The changes will include the addition of a Pulse Forming Line parallel to the existing PFN to power the kicker magnets MKP-S. With the PFL a reduced magnetic field rise time of 100 ns should be reached. The missing deflection strength will be given by two new septum magnets MSI-V, to be installed between the existing septum MSI and the kickers MKP-S. A dedicated ion dump will be installed downstream of the injection elements. The parameter lists of the elements and studies concerning emittance blow-up coming from the injection system are presented. The feasibility of the 100 ns kicker rise time and the small ripple of the septum power converter are presented. Material studies of the ion dump are presented together with the radiation impact.

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THPF104

Design of a Scaled High Duty Factor High Current Negative Penning Surface Plasma Source

plasma, cathode, electron, simulation

3956

D.C. Faircloth, S.R. Lawrie, T. Rutter, M. Whitehead, T. Wood
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
V.G. Dudnikov
Muons, Inc, Illinois, USA

The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) requires a 60 mA, 2 ms, 50 Hz H− beam. The present source can only deliver the current and pulse length requirements at 25 Hz. At 50 Hz there is too much droop in the beam current. To rectify this, a scaled source is being developed. This paper details the new source design and the experiments conducted that are guiding the design.

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THPF105

Status of the RAL Front End Test Stand

rfq, emittance, proton, quadrupole

3959

A.P. Letchford, M.A. Clarke-Gayther, M. Dudman, D.C. Faircloth, S.R. Lawrie
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
S.M.H. Alsari, M. Aslaninejad, J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
J.J. Back
University of Warwick, Coventry, United Kingdom
G.E. Boorman, A. Bosco, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
R.T.P. D'Arcy, S. Jolly
UCL, London, United Kingdom
J.K. Pozimski
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

The Front End Test Stand (FETS) under construction at RAL is a demonstrator of front end systems for future high power proton linacs. Possible applications include a linac upgrade for the ISIS spallation neutron source, new future neutron sources, accelerator driven sub-critical systems, high energy physics proton drivers etc. Designed to deliver a 60mA H-minus beam at 3MeV with a 10% duty factor, FETS consists of a high brightness surface plasma ion source, magnetic solenoid low energy beam transport (LEBT), 4-vane 324MHz radio frequency quadrupole and medium energy beam transport (MEBT) containing a high speed beam chopper and non-destructive laser diagnostics. This paper describes the current status of the project and future plans.

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THPF108

EBIS Charge Breeder at ANL and its Integration into ATLAS

beam-transport, dipole, simulation, electron

3969

A. Perry, A. Barcikowski, G.L. Cherry, C. Dickerson, B. Mustapha, P.N. Ostroumov
ANL, Argonne, Illinois, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract DE-AC02-06CH11357.
An Electron Beam Ion Source charge breeder (EBIS-CB) has been developed to breed CARIBU radioactive beams at ATLAS and is in the final stages of off-line commissioning. Within the next year, the EBIS-CB will replace the existing ECR charge breeder to increase the intensity and improve the purity of reaccelerated radioactive ion beams. Integration of the new EBIS-CB requires: a. Building a compact fully electrostatic low energy beam transport line (LEBT) from CARIBU to the EBIS-CB that satisfies the spatial constraints and ensures the successful ion seeding into the EBIS trap. b. Modifications to the existing ATLAS LEBT to purify the EBIS beams by q/A selection and accommodate the injection of the charge bred ions into ATLAS. In this paper, we will describe the beam line design and present beam dynamics simulation results.

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THPF110

Offline Testing of the CARIBU EBIS Charge Breeder

electron, operation, ion-source, rfq

3973

C. Dickerson, S.A. Kondrashev, P.N. Ostroumov, R.C. Vondrasek
ANL, Argonne, Illinois, USA
A. Perry
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under contract number DE-AC02-06CH11357.
In 2015 an electron beam ion source (EBIS) will be installed at the ATLAS facility to charge breed radioactive beams from the Californium Rare Isotope Breeder Upgrade (CARIBU). Currently an ECR ion source is used to charge breed CARIBU beams. The EBIS will provide beams with much less contamination and higher breeding efficiencies. In preparation for its installation at ATLAS the EBIS has been successfully commissioned offline. The EBIS was configured in the offline facility to closely mimic the conditions expected in the ATLAS installation, so commissioning results should be representative of its performance with CARIBU. The EBIS breeding efficiency was tested with pulses of 133Cs¹⁺ from a surface ionization source, and for multiple operational modes maximum breeding efficiencies greater than 25% could be achieved. After transmission losses the total efficiency of the system was 15-20%. The contaminants were expectedly very low for a UHV system with nominal pressures of ~1 – 3 x 10^-10 Torr.

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THPF123

Modeling Proton- and Light Ion-Induced Reactions at Low Energies in the MARS15 Code

proton, neutron, target, light-ion

4003

I.L. Rakhno, N.V. Mokhov
Fermilab, Batavia, Illinois, USA
K. K. Gudima
Institute of Applied Physics, Chisinau, Republic of Moldova

Funding: This work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
Correct predictions of secondary particles generated in proton-nucleus interactions below a few tens of MeV is required for radiation studies for front-end of many proton accelerators, energy deposition studies for detectors, radiation damage calculations. Cascade models of various flavors fail to properly describe this energy region. Therefore, we opted to use the existing TENDL library provided in the ENDF/B format in the energy range from 1 to 200 MeV. A much more time-consuming approach utilized in a modified code ALICE was also looked at. For both the options, the energy and angle distributions of all secondary particles are described with the Kalbach-Mann systematics. The following secondaries are taken into account: gammas, nucleons, deuterons, tritons, He-3, He-4 and all generated residual nuclei. Comparisons with experimental data for both the options are presented. The corresponding software is written in C++. Initialization of required evaluated data is performed dynamically whenever the modeling code encounters a nuclide not accounted for yet. It enables us to significantly reduce the amount of requested memory for extended systems with large number of materials.

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THPF126

PXIE Low Energy Beam Transport Commissioning

solenoid, emittance, ion-source, simulation

4013

L.R. Prost, M.L. Alvarez, R. Andrews, J.-P. Carneiro, R.T.P. D'Arcy, B.M. Hanna, V.E. Scarpine, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA
R.T.P. D'Arcy
UCL, London, United Kingdom
C. Wiesner
IAP, Frankfurt am Main, Germany

Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
The Proton Improvement Plan II at Fermilab is a program of upgrades to the injection complex [1]. At its core is the design and construction of a CW-compatible, pulsed H⁻ superconducting RF linac. To validate the concept of the front-end of such machine, a test accelerator (a.k.a. PXIE) is under construction [2]. It includes a 10 mA DC, 30 keV H⁻ ion source, a 2m-long LEBT, a 2.1 MeV CW RFQ, followed by a MEBT that feeds the first of 2 cryomodules taking the beam energy to ~25 MeV, and a High Energy Beam Transport section (HEBT) that takes the beam to a dump. The ion source and LEBT, which includes 3 solenoids, several clearing electrodes/collimators and a chopping system, have been built, installed, and commissioned to full specification parameters. This report presents the outcome of our commissioning activities, including phase-space measurements at the end of the beam line under various neutralization schemes obtained by changing the electrodes’ biases and chopper parameters.

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THPF127

Scheme for a Low Energy Beam Transport with a Non-neutralized Section

space-charge, emittance, ion-source, rfq

4016

A.V. Shemyakin, L.R. Prost
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
A Low Energy Beam Transport (LEBT) line is the part of a modern ion accelerator between an ion source (IS) and a Radio-Frequency Quadrupole (RFQ). Typically, it includes 1-3 solenoidal lenses for focusing and relies on transport dynamics with nearly complete beam space charge neutralization over the entire length of the LEBT. In this paper, we discuss the possibility and rationality of imposing un-neutralized transport in the portion of the LEBT adjacent to the RFQ. For estimations, we will use the parameters from PXIE, a test accelerator presently being constructed at Fermilab.

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THPF141

Design of a Compact All-Permanent Magnet ECR Ion Source Injector for ReA at MSU NSCL

ECR, ion-source, injection, extraction

4054

A.N. Pham, P. Glennon, A. Lajoie, D. Lawton, D. Leitner, G. Machicoane, J. Ottarson, M. Portillo, J. Wenstrom
NSCL, East Lansing, Michigan, USA

Funding: Work supported by Michigan State University and the National Science Foundation Grant PHYS-1102511.
The design of a compact all-permanent magnet electron cyclotron resonance (ECR) ion source injector for the ReAccelerator Facility (ReA) at the Michigan State University (MSU) National Superconducting Cyclotron Laboratory (NSCL) is currently being carried out. The ECR ion source injector will augment the electron beam ion trap (EBIT) charge breeder as an off-line stable ion beam injector for the ReA linac. The objective of the ECR ion source injector will be to provide CW beams of heavy ions from hydrogen to masses up to 136Xe within the ReA charge-to-mass ratio (Q/A) operational range from 0.2 to 0.5. The ECR ion source will be mounted on a high-voltage platform that can be adjusted to provide the required 12 keV/u injection energy into a room temperature radio-frequency quadrupole (RFQ) for further acceleration. The beam line consists of a 30 kV tetrode extraction system, mass analyzing section, and optical matching section for injection into the existing ReA Low Energy Beam Transport (LEBT) line. The design of the ECR ion source and the associated beam line are discussed.

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THPF142

High Intensity Source of He Negative Ions

ion-source, target, polarization, electron

4057

V.G. Dudnikov
Muons, Inc, Illinois, USA
A.V. Dudnikov
BINP SB RAS, Novosibirsk, Russia
V.S. Morozov
JLab, Newport News, Virginia, USA

He- ion can be formed by an attachment of additional electron to the excited metastable 23S1 He atom. Electron affinity in this metastable He- ion is A=0.08 eV with excitation energy 19.8 eV. Production of He- ions is difficult because the formation probability is very small but destruction probability is very high. Efficiency of He- ions generation was improved by using of an alkali vapor targets for charge exchange He- sources. Low current He- beams were used in tandem accelerators for research and technological diagnostics (Rutherford scattering). The development of high-intensity high-brightness arc-discharge ion sources at the Budker Institute of Nuclear Physics (BINP) has opened up an opportunity for efficient production of more intense and more brighter He- beam which can be used for alpha particles diagnostics in a fusion plasma and for realization of a new type of a polarized 3He− ion source. This report discusses the high intense He- beams production and a polarized 3He− ion source based on the large difference of extra-electron auto-detachment lifetimes of the different 3He− ion hyperfine states.

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THPF143

Saddle Antenna RF Ion Sources for Efficient Positive and Negative Ions Production

plasma, extraction, operation, electron

4060

V.G. Dudnikov, R.P. Johnson
Muons, Inc, Illinois, USA
G. Dudnikova
UMD, College Park, Maryland, USA
B. Han, S.N. Murray, T.R. Pennisi, C. Piller, M. Santana, M.P. Stockli, R.F. Welton
ORNL, Oak Ridge, Tennessee, USA

Funding: Work supported in part by US DOE Contract DE-AC05-00OR22725 and by STTR grant DE-SC0011323.
Existing RF Surface Plasma Sources (SPS) for accelerators have specific efficiencies for H⁺ and H⁻ ion generation ~3-5 mA/cm² kW, where about 50 kW of RF power is typically needed for 50 mA beam current production. The Saddle Antenna (SA) SPS described here was developed to improve H⁻ ion production efficiency, reliability and availability. In SA RF ion source the efficiency of positive ion generation in the plasma has been improved to 200 mA/cm² kW. After cesiation, the current of negative ions to the collector was increased from 1 mA to 10 mA with RF power ~1.5 kW in the plasma (6 mm diameter emission aperture) and up to 30 mA with ~4 kW RF. Continuous wave (CW) operation of the SA SPS has been tested on the test stand. The general design of the CW SA SPS is based on the pulsed version. Some modifications were made to improve the cooling and cesiation stability. CW operation with negative ion extraction was tested with RF power up to 1.8 kW from the generator (~1.2 kW in the plasma) with production up to Ic=7 mA. Long term operation was tested with 1.2 kW from the RF generator (~0.8 kW in the plasma) with production of Ic=5 mA, Iex ~15 mA (Uex=8 kV, Uc=14 kV).

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THPF147

Increasing the Beam Brightness of a Duoplasmatron Proton Ion Source

emittance, extraction, brightness, ion-source

4070

Y.K. Batygin, I.N. Draganic, C.M. Fortgang
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396
The LANSCE accelerator facility operates with two independent ion injectors for H⁺ and H⁻ particle beams. The H⁺ ion beam is formed using a duoplasmatron source followed by a 750 keV Cockroft-Walton accelerating column. Formation of an optimal plasma meniscus is an important feature for minimizing beam emittance and maximizing beam brightness. An experimental study was performed to determine optimal conditions of extracted H⁺ beam for maximizing beam brightness. Study was based on measurements of beam emittance versus variable beam current and extraction voltage. Measurements yielded 0.52 as the best ratio of beam perveance to Child - Langmuir perveance for maximizing beam brightness. As a result of optimization, beam brightness was increased by a factor of 2.

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THPF148

LANSCE H⁺ RFQ Status

rfq, beam-transport, ion-source, linac

4073

R.W. Garnett, Y.K. Batygin, C.A. Chapman, I.N. Draganic, C.M. Fortgang, S.S. Kurennoy, R.C. McCrady, J.F. O'Hara, E.R. Olivas, L. Rybarcyk, H.R. Salazar
LANL, Los Alamos, New Mexico, USA
J. Haeuser
Kress GmbH, Biebergemuend, Germany
B. Koubek, A. Schempp
IAP, Frankfurt am Main, Germany

Funding: This work is supported by the U. S. Department of Energy Contract DE-AC52-06NA25396.
The LANSCE linear accelerator at Los Alamos National Laboratory provides H⁻ and H⁺ beams to several user facilities that support Isotope Production, NNSA Stockpile Stewardship, and Basic Energy Science programs. These beams are initially accelerated to 750 keV using Cockcroft-Walton (CW) based injectors that have been in operation for over 37 years. To reduce long-term operational risks and to realize future beam performance goals for LANSCE we are completing fabrication of a 4-rod Radio-Frequency Quadrupole (RFQ) and design of an associated beam transport line that together will eventually become the modern injector replacement for the existing obsolete H⁺ injector system. A similar H⁻ system is also planned for future implementation. An update on the status and progress of the project will be presented.

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FRXB1

The DOE Long-Term Accelerator R&D Stewardship Program

laser, cyclotron, experiment, controls

4082

E.R. Colby
OHEP/DOE, Germantown, Maryland, USA
M. Farkhondeh
DOE/NP, Germantown, USA
E.S. Lessner
DOE/BES, Germantown, Maryland, USA
M.S. Zisman
US DOE, Washington, USA

Funding: U. S. Department of Energy, Office of Science
Since the Accelerators for America's Future (AfAF) Symposium in 2009, the U. S. Dept. of Energy's Office of High Energy Physics (DOE-HEP) has worked to broaden its accelerator R&D activities beyond supporting only discovery science to include medicine, energy and environment, defense and security, and industry. Accelerators play a key role in many aspects of everyday life, and improving their capabilities will enhance U.S. economic competitiveness and the scientific research that drives it. Funded for the first time in 2014, the DOE Office of Science Accelerator Stewardship Program has launched initiatives to facilitate access to DOE accelerator infrastructure, develop innovative accelerator technologies that solve critical problems, and catalyze new partnerships across the accelerator user community. We will discuss the formulation and evolution of the Accelerator Stewardship program, the current status of initiatives, and plans for engagement with the accelerator and user communities for future stewardship activities.

Slides FRXB1 [3.429 MB]

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FRXB3

Advances in CW Ion Linacs

linac, rfq, cavity, cryomodule

4085

P.N. Ostroumov
ANL, Argonne, Illinois, USA

Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics and Nuclear Physics, under Contracts DE-AC02-76CH03000 and DE-AC02-06CH11357.
Substantial research and development related to CW proton and ion accelerators are being performed at ANL. A normal conducting CW RFQ and a 4K cryomodule with seven quarter-wave resonators (QWR) and SC solenoids have been developed, built, commissioned and operated as an upgrade of the CW ion linac, ATLAS, to achieve higher efficiency and beam intensities. The new CW RFQ and cryomodule were fully integrated into ATLAS and have been in routine operation for more than a year. Currently we are engaged in development of the first cryomodule for a CW H linac being built at FNAL. This work is well aligned with the development of a 1 GeV 25 MW linac as the driver of a sub-critical assembly for near-term spent nuclear fuel disposal. A 2K cryomodule with eight 162.5-MHz SC half wave resonators (HWR) and eight SC solenoids is being developed for FNAL and scheduled for commissioning in 2017. The testing of the first 2 HWRs demonstrated remarkable performance. Experience with the development and reliable operation of new copper and superconducting accelerating structures is an essential precursor for advanced, reliable future large scale high power CW accelerators.

Slides FRXB3 [4.963 MB]

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FRXC1

The Luminosity Upgrade at RHIC

luminosity, heavy-ion, operation, lattice

4091

G. Robert-Demolaize
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Starting with the high energy heavy ion run for Fiscal Year 07 (Run7), the Relativistic Heavy Ion Collider (RHIC) underwent a series of upgrades in all three tiers of its activities: machine hardware, lattice design and operational efficiency. The following presents a review of these upgrades and how their combined contributions to heavy ion operations lead to average store luminosities that exceed the initial RHIC design by a factor of 25.

Slides FRXC1 [4.570 MB]

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