IPAC2015 - List of Keywords (experiment)

Paper	Title	Other Keywords	Page
MOAC1	Awake: the Proof-of-principle R&D Experiment at CERN	proton, laser, electron, plasma	34
	P. Muggli MPI, Muenchen, Germany M. Bernardini, T. Bohl, C. Bracco, A.C. Butterworth, S. Cipiccia, H. Damerau, S. Döbert, V. Fedosseev, E. Feldbaumer, E. Gschwendtner, W. Höfle, A. Pardons, A.V. Petrenko, J.S. Schmidt, M. Turner, H. Vincke CERN, Geneva, Switzerland
	The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) is a proof-of-principle R&D experiment at CERN. It is the world’s first proton driven plasma wakefield acceleration experiment, using a high-energy proton bunch to drive a plasma wakefield for electron beam acceleration. The AWAKE experiment will be installed in the former CNGS facility and uses the 400 GeV proton beam bunches from the SPS, which will be sent to a plasma source. An electron beam will be injected into the plasma cell to probe the accelerating wakefield. Challenging modifications in the area and new installations are required for AWAKE. First proton beam to the experiment is expected late 2016. The accelerating electron physics will start late 2017. This paper gives an overview of the project from a physics and engineering point of view, it describes the main activities, the milestones, the organizational set-up for the project management and coordination.
	Slides MOAC1 [21.632 MB]
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MOPWA009	Channeling Radiation Experiment at Fermilab ASTA	electron, photon, brilliance, detector	95
	D. Mihalcea, P. Piot Northern Illinois University, DeKalb, Illinois, USA D.R. Edstrom, P. Piot, T. Sen Fermilab, Batavia, Illinois, USA W.D. Rush KU, Lawrence, Kansas, USA
	Electron beams with moderate energy ranging from 4 to 50 MeV can be used to produce x-rays through the Channeling Radiation (CR) mechanism. Typically, the x-ray spectrum from these sources extends up to 140 keV and this range covers the demand for most practical applications. The parameters of the electron beam determine the spectral brilliance of the x-ray source. The electron beam produced at the Fermilab new facility Advanced Superconducting Test Accelerator (ASTA) meets the requirements to assemble an experimental high brilliance CR x-ray source. In the first stage of the experiment the energy of the beam is 20 MeV and due to the very low emittance (100 nm) at low bunch charge (20 pC) the expected average brilliance of the x-ray source is 0.8x10⁷ photons/[s-(mm-mrad)²-0.1%BW]. In the second stage of the experiment the beam energy will be increased to 50 MeV and consequently the average brilliance will be 4.8x10⁸ photons/[s-(mm-mrad)²-0.1%BW]. Also, the x-ray spectrum will be extended from about 30 keV to 140 keV.
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MOPWA036	Status of Injection Studies into the Figure-8 Storage Ring	injection, simulation, kicker, ion	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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MOPWA046	Lattice and Beam Dynamics of the Energy Recovery Mode of the Mainz Energy-recovering Superconducting Accelerator MESA	linac, cryomodule, lattice, simulation	220
	D. Simon, K. Aulenbacher, R.G. Heine, F. Schlander IKP, Mainz, Germany
	Funding: Work supported by the German Federal Ministry of Education and Research (BMBF) and German Research Foundation (DFG) under the Cluster of Excellence PRISMA. The mainz energy recovering superconducting accelerator (MESA) is a proposed multi-turn energy recovery linac for particle physics experiments. It will be built at the institute for nuclear physics (KPH) at Mainz University. Because of the multi-turn energy recovery mode there are particular demands at the beam dynamics. We present the current status of the lattice development.
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MOPJE023	3D Computer Simulations of the Ultrarelativistic Beam Dynamics in Super Colliders	simulation, collider, focusing, plasma	326
	M.A. Boronina, V.A. Vshivkov ICM&MG SB RAS, Novosibirsk, Russia G. Dudnikova ICT SB RAS, Novosibirsk, Russia
	Funding: The work is supported by RFBR Grants 14-01-31088, 14-01-00392, 14-07-00241. The problem of numerical modeling of beam-beam interaction with high relativistic factor (~10⁴) is considered. We present 3D a self-consistent simulation model based on particle-in-cell method. The mixed Euler-Lagrangian decomposition is used in parallel algorithm for achieving good load balancing and reducing communication cost. Stable regimes of beam dynamics, depending on the beams configuration (beta-function, emittance, energy, currents and relative offset) can be found on the base of the model. In the calculations we used 10⁸ particles on the grid 100x100x100, the number of processors depends highly on the beam shape. The Lomonosov Super Computer and Siberian Supercomputer Centre cluster were used to perform the presented simulations.
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MOPJE044	Beam Dynamics Studies of the ELENA Electrostatic Transfer Lines	quadrupole, antiproton, optics, simulation	385
	M.A. Fraser, W. Bartmann, R. Ostojić CERN, Geneva, Switzerland D. Barna University of Tokyo, Tokyo, Japan
	The low-energy ELENA ring at the Antiproton Decelerator (AD) facility at CERN will lower the kinetic energy of antiproton beams from 5.3 MeV to 100 keV, significantly increasing the antiproton trapping efficiency at the experiments. The antiprotons from ELENA will be distributed to two experimental areas housing several different experiments through a system of electrostatic transfer lines totalling 90 m in length. A significant optimisation of the electrostatic optical elements (deflectors, quadrupoles, and correctors) has been carried out to improve the beam quality delivered to the experiments and facilitate installation of the beam lines into the AD hall. A general overview of the beam optics is presented, including end-to-end particle tracking and error studies from the extraction point in the ELENA ring to the experiments.
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MOPJE077	Progress on Simulation of Fixed Field Alternating Gradient Accelerators	simulation, closed-orbit, betatron, acceleration	495
	S.L. Sheehy JAI, Oxford, United Kingdom A. Adelmann PSI, Villigen PSI, Switzerland M. Haj Tahar, F. Méot BNL, Upton, Long Island, New York, USA Y. Ishi, Y. Kuriyama, Y. Mori, M. Sakamoto, T. Uesugi Kyoto University, Research Reactor Institute, Osaka, Japan D.J. Kelliher, S. Machida, C.R. Prior, C.T. Rogers STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	Fixed Field Alternating Gradient accelerators have been realised in recent decades thanks partly to computational power, enabling detailed design and simulation prior to construction. We review the specific challenges of these machines and the range of different codes used to model them including ZGOUBI, OPAL and a number of in-house codes from different institutes. The current status of benchmarking between codes is presented and compared to the results of recent characterisation experiments with a 150 MeV FFAG at KURRI in Japan. Finally, we outline plans toward ever more realistic simulations including space charge, material interactions and more detailed models of various components.
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MOPJE084	Particle-in-cell Simulations of a Plasma Lens at Daresbury Laboratory	plasma, focusing, emittance, simulation	518
	K. Hanahoe, O. Mete, G.X. Xia UMAN, Manchester, United Kingdom D. Angal-Kalinin, J.K. Jones STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom J.D.A. Smith TXUK, Warrington, United Kingdom
	Feasibility of a focusing element using the transverse fields provided by a plasma cell was studied numerically. In this paper, an experimental set up is proposed for various beam parameters available from the VELA and CLARA beam lines at Daresbury Laboratory. 2D simulation results from VSim, and expected results from planned measurement stations are presented. Field properties and the advantages and disadvantages of such an instrument compared to conventional focusing elements are discussed.
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MOPMA022	Numerical Analysis of Parasitic Crossing Compensation with Wires in DAΦNE	positron, luminosity, beam-beam-effects, collider	589
	A. Valishev Fermilab, Batavia, Illinois, USA C. Milardi, M. Zobov INFN/LNF, Frascati (Roma), Italy D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	Funding: This work was partially supported by the US LARP. The HiLumi LHC Design Study is partially funded by the European Commission Grant Agreement 284404. Current bearing wire compensators were successfully used in the 2005-2006 running of the DAΦNE collider to mitigate the detrimental effects of parasitic beam-beam interactions. A marked improvement of the positron beam lifetime was observed in machine operation with the KLOE detector. In view of the possible application of wire beam-beam compensators for the High Luminosity LHC upgrade, we revisit the DAΦNE experiments. We use an improved model of the accelerator with the goal to validate the modern simulation tools and provide valuable input for the LHC upgrade project.
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MOPMA049	Development of a Single-pass Amplifier for an Optical Stochastic Cooling Proof-of-principle Experiment at Fermilab's IOTA facility	laser, undulator, radiation, focusing	659
	M.B. Andorf, P. Piot Northern Illinois University, DeKalb, Illinois, USA V.A. Lebedev, P. Piot Fermilab, Batavia, Illinois, USA
	Optical stochastic cooling (OSC) is a method of beam cooling which is expected to provide cooling rates orders of magnitude larger than ordinary stochastic cooling. Light from an undulator (the pickup) is amplified and fed back onto the particle beam via another undulator (the kicker). Fermilab is currently exploring a possible proof-of-principle experiment of the OSC at the integrable-optics test accelerator (IOTA) ring. To implement effective OSC a good correction of phase distortions in the entire band of the optical amplifier is required. In this contribution we present progress in experimental characterization of phase distortions associated to a Titanium Sapphire crystal laser-gain medium (a possible candidate gain medium for the OSC experiment to be performed at IOTA). We also discuss a possible option for a mid-IR amplifier.
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MOPMN020	Longitudinal Impedance of RHIC	synchrotron, impedance, storage-ring, scattering	746
	M. Blaskiewicz, J.M. Brennan, K. Mernick 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 longitudinal impedance of the two RHIC rings has been measured using the effect of potential well distortion on longitudinal Schottky measurements. With Z/n about 5 Ω the impedance of the yellow ring is roughly twice that of the blue ring.
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MOPHA015	Measurement of Momentum Compaction Factor via Depolarizing Resonances at ELSA	resonance, polarization, electron, extraction	811
	J.F. Schmidt, W. Hillert, M. Schedler, J.-P. Thiry ELSA, Bonn, Germany
	Funding: DFG Measuring beam depolarization at energies in close proximity to a depolarizing integer resonance is an established method to determine the beam energy of a circular accelerator. This technique offers high accuracy due to the small resonance widths. Thus, also other accelerator parameters related to beam energy can be measured based on this method. This contribution presents a measurement of the momentum compaction factor with a high precision of 10^-4. It was performed at the 164 m stretcher ring of the Electron Stretcher Facility ELSA at Bonn University, which provides a polarized electron beam of up to 3.2 GeV.
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MOPHA039	A Fast Gated Intensified Camera Setup for Transversal Beam Diagnostics at the ANKA Storage Ring	storage-ring, radiation, synchrotron, bunching	872
	P. Schütze, A. Borysenko, E. Hertle, N. Hiller, B. Kehrer, A.-S. Müller, P. Schönfeldt KIT, Karlsruhe, Germany
	ANKA, the synchrotron light source at Karlsruhe Institute of Technology (KIT), can be operated in different modes including the short bunch operation with bunch lengths compressed to a few picoseconds. In this mode, coherent synchrotron radiation (CSR) is emitted leading to beam instabilities. For gaining further insight into those processes, a setup based on a fast gated intensified camera was installed recently at the visible light diagnostics beamline of the ANKA storage ring. The experimental layout consists of an optical setup, which magnifies the image of the beam in the horizontal and demagnifies it in the vertical plane to obtain a projection of the horizontal beam shape, the camera itself and a fast scanning galvanometric mirror that sweeps this image across the sensor. This allows the tracking of the horizontal bunch size and position over many turns. In this paper we present the setup and show first measurement results.
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MOPHA044	Testing a Digital Beam Position Stabilization for the P2-experiment at MESA	FPGA, feedback, controls, electron	888
	M. Dehn, K. Aulenbacher, J. Diefenbach, F. Fichtner, R. Herbertz, W. Klag IKP, Mainz, Germany
	Funding: Work supported by the German Federal Ministry of Education and Research (BMBF) and German Research Foundation (DFG) under the Collaborative Research Center 1044 and the Cluster of Excellence "PRISMA" The Mainz Energy recovering Superconducting Accelerator (MESA) will be built at the institute for nuclear physics at Mainz University. Besides the multi-turn energy recovery mode an external beam mode is foreseen to provide 155 MeV electrons of 85% polarization at 150 μA for parity violating experiments. To achieve the required stability of the main beam parameters a dedicated digital position stabilization is currently developed and tested at the Mainz Microtron (MAMI).
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MOPTY014	An Experimental Study of Higher-Order Modes Excited by High Repetition Rate Electron Beam in an SRF Cavity	HOM, electron, SRF, cavity	965
	Y. Gao, J.E. Chen, L.W. Feng, J.K. Hao, S. Huang, L. Lin, K.X. Liu, X. Luo, S.W. Quan, F. Wang, Zh.W. Wang PKU, Beijing, People's Republic of China
	Funding: National Natural Science Foundation of China (No. 11275014) Higher-order modes (HOMs) excited by electron beam traversing a superconducting rf (SRF) cavity contain lots of information and can be used for intra-cavity electron beam diagnostics. Unlike single bunch, multiple bunches would excite HOMs with a much complicated spectrum. In this paper, we present our recent research on HOMs excited by a high repetition rate electron beam in an SRF cavity. Especially, we focus on the integer multiple frequency peaks in the HOM spectrum, which are determined by the nearest eigen HOM peaks. The experiments were carried out on the DC-SRF photoinjector, which was operated at MHz repetition rate. The results agree well with theoretic analysis.
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MOPTY022	Bunch by Bunch DBPM Processor Development and Preliminary Experiment in SSRF*	injection, hardware, betatron, FPGA	984
	Y.B. Leng, Z.C. Chen, L.W. Lai, Y.B. Yan, Y. Yang SSRF, Shanghai, People's Republic of China
	Funding: Work supported by Chinese NSFC11375255. Digital BPM processor with turn-by-turn capability has been widely used in synchrotron radiation facilities over the world, which is proved to be very useful and powerful for daily operation and linear optics study but not good enough in the case of individual bunch information required. In order to sufficient individual bunch diagnostics requirements a development plan of the next generation DBPM processor with bunch-by-bunch capability has been initiated in SINAP since 2012. The whole development was divided into three steps: a concept processor based on digital oscilloscope IOC, an algorithm prototype processor based on commercial high speed ADC board, and a custom designed dedicated processor. The progress of this work and several preliminary beam experiments will be discussed in this paper.
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MOPTY045	ESS Availability and Reliability Approach	neutron, operation, proton, target	1033
	E. Bargalló, K.H. Andersen, R. Andersson, A. De Isusi, A. Nordt, E.J. Pitcher ESS, Lund, Sweden
	Reliability and availability are key metrics for achieving the scientific vision of the ESS. The approach taken to analyze and to improve these metrics in order to achieve the goals is described in this contribution. The methodology used to obtain the requirements considers not only the availability and reliability figures but also the specific needs extracted from users expectations from the neutron source in order to succeed in their experiments. A top-down requirements allocation is being developed at the same time that bottom-up reliability and availability analyses is being performed. The experiments expected at ESS and their needs in terms of neutron beam performance (reliability, availability and quality) are described as well as the tools used to analyze it. Moreover, the consequences of these analyses in the design phase are discussed.
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MOPTY052	Experimental and Simulation Studies of Hydrodynamic Tunneling of Ultra-Relativistic Protons	target, simulation, proton, cavity	1048
	F. Burkart, R. Schmidt, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland A.R. Piriz Universidad de Castilla-La Mancha, Ciudad Real, Spain A. Shutov IPCP, Chernogolovka, Moscow region, Russia N.A. Tahir GSI, Darmstadt, Germany
	The expected damage due to the release of the full LHC beam energy at a single aperture bottleneck has been studied. These studies have shown that the range of the 7 TeV LHC proton beam is significantly extended compared to that of a single proton due to hydrodynamic tunneling effect. For instance, it was evaluated that the protons and their showers will penetrate up to a length of 25 m in solid carbon compared to a static range of around 3 m. To check the validity of these simulations, beam- target heating experiments using the 440 GeV proton beam generated by the SPS were performed at the HiRadMat test facility at CERN . Solid copper targets were facially irradiated by the beam and measurements confirmed hydrodynamic tunneling of the protons and their showers. Simulations have been done by running the energy deposition code FLUKA and the 2D hydrodynamic code, BIG2, iteratively. Very good agreement has been found between the simulations and the experimental results * providing confidence in the validity of the studies for the LHC. This paper presents the simulation studies, the results of a benchmarking experiment, and the detailed target investigations. * N.A. Tahir et al., Phys. Rev. Special Topics Accel. Beams 15 (2012) 051003. ** R. Schmidt et al., Phys. Plasmas 21 (2014) 080701.
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MOPTY058	Response of Polycrystalline Diamond Particle Detectors Measured with a High Intensity Electron Beam	detector, electron, radiation, beam-losses	1069
	O. Stein, F. Burkart, B. Dehning, R. Schmidt, C.B. Sørensen, D. Wollmann CERN, Geneva, Switzerland E. Griesmayer CIVIDEC Instrumentation, Wien, Austria
	Comprehensive understanding of beam losses in the LHC is required to ensure full machine protection and efficient operation. The existing BLM system using ionization chambers is not adequate to resolve losses with a time resolution below some 10 us. Ionization chambers are also not adequate to measure very large transient losses, e.g. beam impacting on collimators. Diamond particle detectors with bunch-by-bunch resolution have therefore been used in LHC to measure fast particle losses with a time resolution down to a level of single bunches. Diamond detectors have also successfully been used for material damage studies in other facilities, e.g. HiRadMat at the CERN-SPS. To fully understand their potential, such detectors were characterized with an electron beam at the BTF in LNF INFN Italy, with bunch intensities from 10³ to 10⁹ electrons. The detector response and efficiency has been measured with a 50 Ω and a 1 Ω read-out system. This paper describes the experimental setup and the results of the experiment. In particular, the responses of three samples of 100 um single-crystalline diamond detectors and two samples of 500 um polycrystalline diamond detectors are presented.
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MOPTY060	Pulse Compressor Phase and Amplitude Modulation Based on Iterative Learning Control	klystron, controls, operation, linac	1076
	A. Řežaeizadeh, R. Kalt, T. Schilcher PSI, Villigen PSI, Switzerland R. Smith Automatic Control Laboratory, ETH Zurich, Zurich, Switzerland
	This paper presents an alternative way to produce flat-topped RF pulses at the pulse compressor output. Flat-topped RF pulses are suitable for multi-bunch operation where it is often required that beams experience the same accelerating gradient. Moreover, the energy gain, in this case, is less sensitive to timing jitters. The proposed approach is based on Iterative Learning Control technique, which iteratively updates the input waveforms, in order to generate the desired output waveforms.
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MOPTY062	The Energy Saving Processes for Utility System in TPS	controls, operation, photon, factory	1082
	C.S. Chen, W.S. Chan, J.-C. Chang, Y.C. Chang, Y.-C. Chung, C.W. Hsu, C.Y. Liu, Z.-D. Tsai NSRRC, Hsinchu, Taiwan
	There are more and more non-linear electronic equipments such as inverters using in facility nowadays. These non-linear electronic equipments let us achieve energy saving, but induce other electrical pollution to the whole power grid in contrast. Among these electrical pollutions, electric harmonic is the most common and harmful to power facility. Therefore, how to monitor the electrical noises from these non-linear equipments becomes an important issue. In this article, a set of power quality monitoring system based on FPGA (Field-Programmable Gate Arrays) modules and PAC (Programmable Automatic Controller) has been built because of their programmability and fast processing speed. By using this monitoring system, any abnormality in power system and its spectrum will be recorded thoroughly. On the other hand, the maintainer could follow the trace of noise and then propose a suitable solution to eliminate the electrical interference too.
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MOPWI004	Novel Single Shot Bunch Length Diagnostic using Coherent Diffraction Radiation	electron, radiation, laser, optics	1150
	R.B. Fiorito, C.P. Welsch, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom A.G. Shkvarunets UMD, College Park, Maryland, USA
	Funding: European Union’s grant agreement no. 624890 and STFC Cockcroft core grant No. ST/G008248/1; US Office of Naval Research and DOD Joint Technology Office. Current beam bunch length monitors which measure the spectral content of beam-associated coherent radiation to determine the longitudinal bunch form factor usually require wide bandwidth detection or Fourier transformation of interferometric data and multiple beam pulses. The data must then be Fourier transformed to obtain the bunch length. In this contribution we discuss progress in the development of a novel single shot method that utilizes the frequency integrated angular distribution (AD) of coherent diffraction radiation (CDR) to measure the RMS bunch length directly. We also present simulation results which show how the AD changes with bunch length for several electron beam linacs, where we are planning to test this new method, our single shot measurement technique and plans for comparison to other bunch length monitors.
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MOPWI006	Development of a Supersonic Gas-jet Monitor to Measure Beam Profile Non-destructively	ion, vacuum, electron, storage-ring	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	ion, electron, diagnostics, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI009
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MOPWI015	A Low Time-Dispersion Refractive Optical Transmission Line for Streak Camera Measurements	electron, database, resonance, plasma	1178
	J.G. Power, G. Ha ANL, Argonne, Illinois, USA G. Ha POSTECH, Pohang, Kyungbuk, Republic of Korea
	Funding: Work supported by the U.S. Department of Energy office of High Energy Physics. Streak camera measurements of the charge particle bunch length are limited in resolution due to several factors: (1) the light from the source (optical transition radiation, Cherenkov, synchrotron radiation, etc.); (2) time dispersion introduced in the optical transmission line between the source and the streak camera; and finally (3) the streak camera resolution. The limiting resolution usually arises from the optical transmission line. While an all-reflective transmission line can eliminate dispersion, the system is complicated and expensive. In this paper, we consider how to design a refractive optical transport line to minimize the time dispersion while maximizing the signal. We present a theoretical model of the dispersion, modeling, and measurements of the time dispersion for several different lens materials.
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MOPWI017	Beam Extinction Monitoring in the Mu2e Experiment	proton, target, detector, shielding	1185
	E. Prebys, A. Gaponenko, P.H. Kasper Fermilab, Batavia, Illinois, USA L.M. Bartoszek Bartoszek Engineering, Aurora, Illinois, USA
	Funding: This work is supported by the US Department of Energy under contract No. De-AC02-07CH11359. The Mu2e Experiment at Fermilab will search for the conversion of a muon to an electron in the field of an atomic nucleus with unprecedented sensitivity. The experiment requires a beam consisting of proton bunches approximately 200ns FW long, separated by 1.7 microseconds, with no out-of-time protons at the 10^-10 fractional level. The verification of this level of extinction is very challenging. The proposed technique uses a special purpose spectrometer which will observe particles scattered from the production target of the experiment. The acceptance will be limited such that there will be no saturation effects from the in-time beam. The precise level and profile of the out-of-time beam can then be built up statistically, by integrating over many bunches.
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MOPWI032	Analysis of Primary Stripper Foils at SNS by an Electron Beam Foil Test Stand	electron, proton, gun, operation	1230
	E.P. Barrowclough, C.S. Feigerle University of Tennessee, Knoxville, Tennessee, USA C.F. Luck, M.A. Plum, R.W. Shaw, L.L. Wilson ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. Diamond foils are used at the Spallation Neutron Source (SNS) as the primary strippers of hydride ions. A nanocrystalline diamond film, typically 17x45 mm with an aerial density of 0.35 mg/cm², is deposited on a corrugated silicon substrate by plasma-assisted chemical vapor deposition. After growth, 30 mm of the silicon substrate is etched away, leaving a freestanding diamond foil with a silicon handle that can be inserted into SNS for operation. An electron beam test facility was constructed to study stripper foil degradation and impact on foil lifetime. The electron beam capabilities include: current up to 5 mA, focused spot size of 0.30 mm², and rastering in the x- and y-directions. A 30 keV and 1.6 mA/mm² electron beam deposits the same power density on a diamond foil as a 1.4 MW beam on SNS target. Rastering of the electron beam can expose a similar area of the foil as SNS beams. Experiments were conducted using the foil test stand to study: foil flutter and lifetime; effects of corrugation patterns, aerial densities, crystal size (micro vs. nano), and boron doping; temperature distributions and film emissivity; and conversion rate of nanocrystalline diamond into graphite.
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MOPWI036	Investigation of Continuous Scan Methods for Rapid Data Acquisition	detector, data-acquisition, software, hardware	1243
	C.L. Li East China University of Science and Technology, Shanghai, People's Republic of China A.M. Kiss SLAC, Menlo Park, California, USA W.J. Zhang University of Saskatchewan, Saskatoon, Canada
	It is common practice to perform spatially resolved X ray data acquisition by automatically moving components to discrete locations and then measuring beam intensity with the system at rest. While effective, scanning in this manner can be time consuming, with motors needing to accelerate, move and decelerate at each location before recording data. Information between data points may be missed unless fine grid scans are performed, which accounts for a further increase of scan time. Recent advances in commercial hardware and software enables a continuous scan capability for a wide range of applications, which saves the start and end of step motors. To compare scanning performance, both step and continuous scan modes were examined using the SPEC command language with both commercial and in-house hardware. The advantages and limitations of each are discussed.
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TUXB3	700 kW Main Injector Operations for NOvA at FNAL	booster, proton, operation, electron	1286
	P. Adamson Fermilab, Batavia, Illinois, USA
	Following a successful career as an antiproton storage and cooling ring, the Fermilab Recycler was repurposed as a proton stacker as part of the NOvA project, in order to increase the maximum NuMI beam power from 400 kW to 700 kW. Using the Recycler to prepare beam for acceleration in the Main Injector, we have been able to increase the beam power delivered to NuMI to a sustained weekly average in excess of 400 kW and a best hourly average of 482.8 kW. I discuss the commissioning progress to date, and describe the remaining steps along the way to achieving the 700 kW design goal.
	Slides TUXB3 [3.401 MB]
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TUYC2	Multi-GeV Plasma Acceleration Results at BELLA	laser, plasma, electron, injection	1319
	A.J. Gonsalves, C. Benedetti, S.S. Bulanov, J. Daniels, E. Esarey, C.G.R. Geddes, H.S. Mao, D.E. Mittelberger, K. Nakamura, C.B. Schroeder, C. Tóth, J. van Tilborg LBNL, Berkeley, California, USA W. Leemans UCB, Berkeley, California, USA
	Funding: U.S. Department of Energy under Contract No. DE-AC02-05CH11231 Laser-plasma accelerators (LPAs)* are being investigated as a compact driver for light sources and high-energy linear colliders. Recently 2 GeV beams were generated by focusing ≈ 100 J laser pulses onto a gas target. We report here on the generation of beams with energy up to 4.2 GeV using 16 J of laser pulse energy at the BErkeley Lab Laser Accelerator (BELLA). This was achieved by using laser pulses of high spatial and temporal quality coupled to a pre-formed capillary discharge waveguide of length 9 cm. The waveguide (in conjunction with self-guiding) allowed for mitigation of diffraction. High spatial quality (Strehl ratio at focus 0.8±0.1) was achieved using a deformable mirror placed before the focusing optic. The dominant contribution to the non-Gaussian content of the focal spot was the near-field intensity profile. For maximum efficiency high-power femtosecond systems employ super-Gaussian near-field profiles of the form I(r)∝e^-2(r/w^N), where I is the intensity, r is the radial coordinate, w is the spot size, and N is the order. Compared with Gaussian laser pulses where N=2, pulses from the BELLA laser system had N=10. Simulations showed that an increased contribution of self-guiding was required to effectively confine the laser energy for optimum acceleration and mitigation of damage to the capillary waveguide. Through appropriate choice of plasma density electron beams with energy up to 4.2 GeV were observed. In this regime the electron beam angular fluctuations were > 2 mrad rms, caused in part by errors in waveguide alignment and by laser-induced damage to the capillary that introduces plasma asymmetry. Improved alignment of the waveguide and mitigation of capillary damage allowed for reduction in angular fluctuations to 0.6 mrad rms. The electron beams had energy of 2.7±0.1 GeV, charge of 150 pC, and divergence less than 1 mrad. E. Esarey, et al., Rev. Mod. Phys. 81, 1229 (2009) X. Wang, et al., Nat. Communications 4, 1988 (2013) * W. P. Leemans, et al., Phys. Rev. Lett. 113, 245002 (2014)
	Slides TUYC2 [13.023 MB]
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TUYC3	Scaling Down Synchronous Acceleration: Recent Results, Current Status, and Future Plans of a Subrelativistic Dielectric Laser Acceleration Project	electron, laser, acceleration, focusing	1325
	J.C. McNeur, P. Hommelhoff, M. Kozak, A. Li, N. Schönenberger, A.D. Tafel University of Erlangen-Nuremberg, Erlangen, Germany
	This talk will describe the latest results using laser powered dielectric accelerators. Recent experiments in the US (SLAC) and Europe (MPQ) have fabricated dielectric accelerators powered with optical lasers and used them to accelerate electrons with gradients between 25 and 300 MeV/m. The latest results will be reviewed and prospects and applications for the future will be discussed.
	Slides TUYC3 [21.295 MB]
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TUBC1	Recent Progress and Operational Status of the Compact ERL at KEK	laser, operation, quadrupole, beam-losses	1359
	S. Sakanaka, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondou, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sasaki, K. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida KEK, Ibaraki, Japan E. Cenni Sokendai, Ibaraki, Japan R. Hajima, S. Matsuba, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma JAEA, Ibaraki-ken, Japan J.G. Hwang KNU, Deagu, Republic of Korea M. Kuriki Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan Y. Seimiya HU/AdSM, Higashi-Hiroshima, Japan
	Funding: Work supported by the Photon and Quantum Basic Research Coordinated Development Program from the MEXT, and by the MEXT grant for promoting technology for nuclear security. The Compact Energy Recovery Linac (cERL) is a superconducting test accelerator aimed at establishing technologies for the ERL-based future light source. After its construction during 2009 to 2013, the first CW beams of 20 MeV were successfully transported through the recirculation loop in February 2014. Then, initial tuning of beams and evaluations of beam properties were carried out. From September to December in 2014, we are constructing a Laser Compton Scattering (LCS) source* which aims at demonstrating technology for the future high-flux quasi-monochromatic gamma-ray source. In the next run of the cERL, which begins at the end of January 2015, we plan such works as an increase in the beam current (from 10 uA to 100 uA), commissioning of the LCS source, and sustained tuning of beams for lower emittance. We will report up-to-date results of these developments. * N. Nakamura et al., IPAC2014, MOPRO110; S. Sakanaka et al., LINAC14, TUPOL01. ** R. Nagai et al., IPAC2014, WEPRO003.
	Slides TUBC1 [2.679 MB]
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TUPWA020	BNL ATF II Beamlines Design	electron, laser, cavity, linac	1445
	M.G. Fedurin, Y.C. Jing, D. Stratakis, C. Swinson 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 Brookhaven National Lab. Accelerator Test Facility (BNL ATF) is currently undergoing a major upgrade (ATF-II). Together with a new location and much improved facilities, the ATF will see an upgrade in its major capabilities: electron beam energy and quality and CO2 laser power. The electron beam energy will be increased in stages, first to 100-150 MeV followed by a further increase to 500 MeV. Combined with the planned increase in CO2 laser power (from 1-100 TW), the ATF-II will be a powerful tool for Advanced Accelerator research. A high-brightness electron beam, produced by a photocathode gun, will be accelerated and optionally delivered to multiple beamlines. Besides the energy range (up to a possible 500 MeV in the final stage) the electron beam can be tailored to each experiment with options such as: small transverse beam size (<10 um), flat beam, short bunch length (<100 fs) and, combined short and small bunch options. This report gives a detailed overview of the ATF-II capabilities and beamlines configuration.
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TUPWA029	ARES: Accelerator Research Experiment at SINBAD	electron, cavity, bunching, linac	1469
	B. Marchetti, R.W. Aßmann, C. Behrens, R. Brinkmann, U. Dorda, K. Flöttmann, J. Grebenyuk, M. Hüning, Y.C. Nie, H. Schlarb, J. Zhu DESY, Hamburg, Germany
	ARES is a planned linear accelerator for R&D for production of ultra-short electron bunches. It will be hosted at the SINBAD facility, at DESY in Hamburg. The goal of ARES is to produce low charge (0.2-50pC), ultra-short (from few fs to sub-fs) bunches, with high arrival time stability (less than 10fs) for various applications, such as external injection for Laser Plasma Wake-Field acceleration. The baseline layout of the accelerator foresees an S-band photo-injector which compresses low charge electron bunches via velocity bunching and accelerates them to 100 MeV energy. In the second stage, it is planned to install a third S-band accelerating cavity to reach 200 MeV as well as two X-band cavities: One for the linearization of the longitudinal phase space (subsequently allowing an improved bunch compression) and another one as a transverse deflecting cavity for longitudinal beam diagnostics. Moreover a magnetic bunch compressor is envisaged allowing to cut out the central slice of the beam** or hybrid bunch compression. * R. Assmann et al., TUPME047, Proceedings of IPAC 2014. R. Assmann, J. Grebenyuk, TUOBB01, Proceedings of IPAC 2014. * P. Emma et al., PRL 92 7 (2004).
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TUPWA045	Further Investigations on the MESA injector	coupling, linac, simulation, space-charge	1515
	R.G. Heine, K. Aulenbacher, S. Friederich, C. Matejcek, F. Schlander IKP, Mainz, Germany
	Funding: work supported by the German Federal Ministery of Education and Research under the Cluster of Excellence "PRISMA" The MESA ERL to be build at Mainz in the next years is a multi turn recirculating linac with beam currents of up to 10 mA. The dynamic range of the beam currents demanded by the experiments is of at least two orders of magnitude. This is a special challenge for the layout design of an injector. In this paper we present the current status of the design of the injector linac called MAMBO (MilliAMpereBOoster).
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TUPWA054	The FERMI Seeded FEL Facility: Operational Experience and Future Perspectives	FEL, laser, electron, operation	1538
	M. Svandrlik, E. Allaria, L. Badano, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, P. Cinquegrana, M. Coreno, R. Cucini, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, P. Finetti, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, L. Giannessi, F. Iazzourene, M. Kiskinova, S. Krecic, M. Lonza, N. Mahne, C. Masciovecchio, M. Milloch, F. Parmigiani, G. Penco, L. Pivetta, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, E. Roussel, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	FERMI is the seeded FEL user facility in Trieste, Italy, producing photons from the VUV to the soft X-rays with a high degree of coherence and spectral stability. Both FEL lines, FEL-1 and FEL-2, are now available for users, down to the shortest wavelength of 4 nm. We will report on the completion of the commissioning of the high energy FEL line, FEL-2, and on the operational experience for users, in particular those requiring specific FEL configurations, like two-colour experiments. We will also give a perspective on the improvements and upgrades which have been triggered by our experience and are aiming to maintain as well as to constantly improve the performance of the facility for our user community.
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TUPWA058	Study of a C-band Harmonic RF System to Optimize the RF Bunch Compression Process of the SPARC Beam	cavity, gun, linac, emittance	1552
	A. Gallo, D. Alesini, M. Bellaveglia, M. Ferrario INFN/LNF, Frascati (Roma), Italy A. Bacci, V. Petrillo, A.R. Rossi, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy F. Cardelli, L. Piersanti INFN-Roma1, Rome, Italy B. Marchetti DESY, Hamburg, Germany M. Rossetti Conti Universita' degli Studi di Milano & INFN, Milano, Italy
	The SPARC linac at the INFN Frascati Labs is a high brilliance electron source with a wide scientific program including production of THz and Thomson backscattering radiation, FEL studies and plasma wave acceleration experiments. The linac is based on S-band RF and consists in an RF Gun followed by 3 accelerating structures, while an energy upgrade based on 2 C-band accelerating structures is ready to be implemented. Short bunches are ordinarily produced by using the linear RF bunch compression concept. A harmonic RF structure interposed between the Gun and the 1st accelerating structure can be used to optimize the RF compression by a longitudinal phase space pre-correction, allowing to reach shorter bunches, a much more uniform current distribution and in general to control better the whole compression process. Here we report the results of numerical studies on the SPARC bunch compression optimization through the use of a harmonic cavity, and the design of a C-band RF system to implement it. The proposed system consists in a multi-cell SW cavity powered by a moderate portion of the total RF power spilled from the C-band power plant already installed for the linac energy upgrade.
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TUPWA062	GaAs Photocathode Activation with CsTe Thin Film	photon, electron, cathode, vacuum	1567
	M. Kuriki, Y. Seimiya, K. Uchida HU/AdSM, Higashi-Hiroshima, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	Funding: This work is partly supported by MEXT/JSPS KAKENHI (Grant-in-Aid for scientific research) 24654054. GaAs is an unique and advanced photocathode which can generate highly polarized and extremely low emittance electron beam. The photo-emission is possible up to 900nm wavelength. These advantages are due to NEA (Negative Electron Affinity) surface where the conduction band minimum is higher than the vacuum energy state. The NEA surface is artificially made with Cs-O/F evaporation on the cleaned GaAs surface, but the NEA surface is fragile, so that the emission is easily lost by poor vacuum environment and high emission density. NEA activation with any vital material is desirable. We found that the GaAs can be activated by CsTe thin film which is known as a vital photo-cathode material. The photo-electron emission spectrum extends up to 900 nm wavelength which corresponds to the band-gap energy of GaAs. The result strongly suggests that the surface becomes effectively NEA state by the CsTe thin film.
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TUPJE004	Narrow Band Coherent Edge Radiation at UVSOR-III	radiation, electron, laser, storage-ring	1613
	M. Hosaka, O. Oodake, Y. Takashima, N. Yamamoto Nagoya University, Nagoya, Japan S. Bielawski, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France M. Katoh, T. Konomi, J. Yamazaki UVSOR, Okazaki, Japan H. Zen Kyoto University, Kyoto, Japan
	Edge radiation can be an interesting new light source because of its property that the radiation is well collimated and is radially polarized. We are developing coherent light sources in the THz region at UVSOR-III storage ring. We have already succeeded in producing a narrow band coherent THz radiation by manipulating the interaction of a relativistic electron bunch with an amplitude modulated laser with. Recently a simplified tentative beamline for detection of the edge radiation is installed at downstream of a short straight section of UVSOR-III. Coherent radiation from electron bunches after the interaction with the amplitude modulated laser is observed. Detailed measurements of polarizations and special distribution of the radiation are underway. The latest status of the study will be reported.
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TUPJE012	Preliminary Result of Photon Counting Acquisition Scheme for Laser Pump/X-ray Probe Experiments	laser, synchrotron, detector, timing	1638
	J. He, J.S. Cao, G. Gao, Y.F. Sui, Y. Tao, J.H. Yue, Z. Zhang, Y.F. Zhou IHEP, Beijing, People's Republic of China
	Funding: This work is supported by the NSFC under grant No.11305186 R&D project has been initiated for a proposed ultralow emittance (~50pm.rad) synchrotron light source built in Beijing. The R&D includes the development of high repetition rate laser pump/X-ray probe for ultrafast dynamics detection in future source. In a typical laser pump/X-ray probe measurement, the X-ray pulse follows a laser pulse in adjustable delay. We are interested in the difference between laser on and laser off at different delay, which will snapshot dynamic process. To capture this trivial difference, it requires the acquisition system to single out the signal from this special X-ray pulse at adequate S/N ratio. For the R&D of high repetition rate pump-probe, we have set up a prototype counting acquisition system based on NIM modular electronics, which was tested in Beijing Synchrotron Radiation Facility (BSRF). The laser will be synchronized with a camshaft bunch at 124 kHz, a tenth of the revolution frequency. Avalanche Photo Diode (APD) was used to detect the X-ray pulse from this camshaft bunch due to its nanosecond response. Before the laser is delivered, we mimic the 124 kHz laser- on signal. The signals from APD are separated by power dividers into two Constant Fraction Discriminator (CFD) input channels. The signal in laser-on/off channel is gated out at 1.24MHz using the 1.24MHz timing signal divided from 499.8 MHz RF signal, while the mimic laser-on signal gated out at 124 kHz. Multiplied by ten times, the mimic laser-on signal counts should be consistent with the laser-on+off counts, if our counting modular works well. We carried out this test at 1W1B wiggler beam line to measure the Fe fluorescence signal. The performance of our system is demonstrated in the good consistency between mimic laser on and laser on+off signals.
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TUPJE058	Preparation of Polycrystalline and Thin Film Metal Photocathodes for Normal Conducting RF Guns	cathode, gun, electron, cavity	1759
	S. Mistry, M.D. Cropper Loughborough University, Leicestershre, United Kingdom A.N. Hannah, K.J. Middleman, B.L. Militsyn, T.C.Q. Noakes, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	A comparison of quantum efficiency (QE) and work function (wf) measurements of polycrystalline and thin film metal photocathodes for use in NCRF guns, similar to the S-band gun under development for CLARA project at Daresbury, are reported. Cu and Nb thin films were grown onto a Si substrate by magnetron sputtering and subsequently were prepared by annealing and Ar ion sputtering. To determine the surface chemistry, x-ray photoelectron spectroscopy was employed. QE measurements were enabled using a UV laser source giving 266 nm light. Wf measurements were carried out using a kelvin probe and ultraviolet photoelectron spectroscopy. Annealing the Cu thin film to 250°C yielded a QE of 1.2E-4; one order of magnitude higher than the QE for sputter cleaned and post annealed polycrystalline Cu. The optimum QE measurement for Nb thin film was 2.6·10^-4, which was found to be comparable to the results obtained for cleaned bulk Nb. Analysis of XPS data of these metals suggest surface composition and surface chemistry are main contributing factors to the QE and WF.
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TUPMA042	THz Radiation Generation in a Multimode Wakefield Structure	radiation, wakefield, electron, linac	1929
	S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA M.G. Fedurin BNL, Upton, Long Island, New York, USA W. Gai, D. Wang, A. Zholents ANL, Argonne, Illinois, USA
	Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0009571 A number of methods for producing sub-picosecond beam microbunching have been developed in recent years. A train of these bunches is capable of generating THz radiation via multiple mechanisms like transition, Cherenkov and undulator radiation. We utilize a bunch train with tunable spacing to selectively excite high order TM0n - like modes in a multimode structure. In this paper we present experimental results obtained at the Accelerator Test Facility of Brookhaven National Laboratory.
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TUPMA043	Experimental Test of Semiconductor Dechirper	electron, wakefield, FEL, emittance	1932
	S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA S. Baturin LETI, Saint-Petersburg, Russia M.G. Fedurin, K. Kusche, C. Swinson BNL, Upton, Long Island, New York, USA W. Gai, S. Stoupin, A. Zholents ANL, Argonne, Illinois, USA
	Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0006299 We report the observation of de-chirping of a linearly chirped (in energy) electron bunch by its passage through a 4 inch long rectangular waveguide loaded with two silicon bars 0.25 inch thick and 0.5 inch wide. Silicon being a semiconductor has a conductivity that allows it to drain the charge fast in case if some electrons get intercepted by the dechirper. At the same time the conductivity is low enough for the skin depth to be large (on the order of 1 cm) making the silicon loaded waveguide a slow wave structure supporting wakefields that dechirp the beam.
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TUPTY027	SixTrack Simulations of Beam Cleaning During High-beta Operation in the LHC	simulation, background, proton, collimation	2060
	R. Bruce CERN, Geneva, Switzerland
	The 1000 m high-beta run in the LHC provided very clean conditions for observing experimental backgrounds. In ATLAS, a much higher background was observed for Beam 2 than for Beam 1, suspected to be caused by upstream showers from beam losses on collimators or aperture. However, no local beam losses were observed in the vicinity. This paper presents SixTrack simulations of the beam cleaning during the high-beta run. The results demonstrate that, for the special optics and collimator settings used, the highest loss location in IR1 is at the TAS absorber just in front of the ATLAS detector, where no beam loss monitor is installed. Furthermore, the highest losses are seen in Beam 2. The results could thus provide a possible explanation of the ATLAS observations, although detailed shower calculations would be needed for a quantitative comparison.
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TUPTY056	Beam-Based Measurements of Long Range Transverse Wakefields in CLIC Main Linac Accelerating Structure	wakefield, positron, electron, linac	2153
	H. Zha, A. Grudiev, A. Latina, D. Schulte, A. Solodko, W. Wuensch CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway G. De Michele EPFL, Lausanne, Switzerland G. De Michele PSI, Villigen PSI, Switzerland N. Lipkowitz, G. Yocky SLAC, Menlo Park, California, USA
	The baseline design of CLIC (Compact Linear Collider) uses X-band accelerating structures in the main linac. Every accelerating structure cell has four waveguides, terminated with individual RF loads, to damp the unwanted long-range transverse wakefields, in order to maintain beam stability in multi-bunch operation. In order to experimentally verify the calculated suppression of the wakefields, a prototype structure has been built and installed in FACET test facility at SLAC. The results of the measurements of the wakefields in the prototype structure by means of positron and electron bunches are presented.
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TUPWI003	Proton Beam Applications for Silicon Bulk Micromachining	proton, ion, 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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TUPWI005	Proton Irradiations of Micro-TOM Red Hairy Roots to Mimic Space Conditions	proton, controls, radiation, framework	2249
	M. Vadrucci, A. Ampollini, G. Bazzano, P. Nenzi, L. Picardi, C. Ronsivalle, V. Surrenti ENEA C.R. Frascati, Frascati (Roma), Italy F. Ambrosini Università di Roma "La Sapienza", SAPIENZA-DIET, Roma, Italy E. Benvenuto, A. Desiderio, S. Massa, C. Snels, M.E. Villani ENEA Casaccia, Roma, Italy
	Funding: Radiation Sources Laboratory UTAPRAD Department ENEA C.R. Frascati Via E. Fermi, 45 00044 Frascati (RM), Italy ENEA The purpose of the BIOxTREME project, launched by ENEA and funded by ASI (Italian Space Agency), is to formulate new biological drugs having a stimulant activity on the immune system finalizing the production for a ready to use resource in Bioregenerative Life Support Systems (BLSSs) for space missions with extended durations, in deep space, and with multiple crews. One of the project tasks is to study the effects of physical insults on plants, simulating cosmic environment on production platforms by static magnetic fields, microgravity and ionizing radiation. In order to examine the biological effects, to test plant radio-resistance and to build dose-response curves we carried out proton irradiations of a tomato cultivar Micro-Tom red hairy roots with the TOP-IMPLART accelerator at the ENEA Frascati Research center. The biological samples were placed in a holder specially made in a movable real-time monitoring chamber calibrated in dose. The fluence-homogeneity measurements over the sample and the calibration of the monitoring system were performed using GafChromic EBT3 films. The paper describes the experimental set-up and reports the preliminary results.
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TUPWI017	Single-shot Multi-MeV Ultrafast Electron Diffraction on VELA at Daresbury Laboratory	electron, gun, FEL, scattering	2278
	L.K. Rudge, D. Angal-Kalinin, J.A. Clarke, F. Jackson, J.K. Jones, A. Kalinin, S.L. Mathisen, J.W. McKenzie, B.L. Militsyn, B.D. Muratori, T.C.Q. Noakes, Y.M. Saveliev, D.J. Scott, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom P. Aden, R.J. Cash, D.M.P. Holland, M.D. Roper STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom P.D. Lane, D.A. Wann University of York, York, United Kingdom M. Surman STFC/DL/SRD, Warrington, Cheshire, United Kingdom J.G. Underwood UCL, London, United Kingdom
	Funding: This work was funded by STFC Accelerator based Ultrafast Electron Diffraction (UED) is a technique for obtaining static structures and for studying sub-100 fs dynamic structural changes on the atomic scale. In this paper we present the first electron diffraction results obtained from the VELA accelerator in 2014. The accelerator was operated to provide typically 4MeV/c electron bunches. Diffraction patterns were observed with <<1 pC transported to the detection screen. Single shot and multi-shot accumulated diffraction data are presented from single crystal and polycrystalline samples, including Au, Al, Pt and C. Contamination of the diffraction pattern with dark current contributions is an issue. A variable size aperture directly in front of the sample offers some mitigation, but at the expense of reduced charge contributing to the diffraction pattern. We discuss future developments for electron diffraction on VELA including further beam optimization, measurement of bunch length with a newly installed Transverse Deflecting Cavity, and the planned developments for pump-probe studies.
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TUPWI028	Varying Amplitude Raster Pattern for High Power Isotope Production Targets	target, isotope-production, flattop, proton	2298
	J.S. Kolski, J. Audia, H.T. Bach, Y.K. Batygin, J.T. Bradley III, M. Connors, J.W. Engle, E. Espinoza, E. Figueroa, M.J. Hall, M.P. Martinez, F.M. Nortier, D. Reass, W. Roybal, H.A. Watkins LANL, Los Alamos, New Mexico, USA
	The Isotope Production Facility (IPF) at LANSCE produces medical radionuclides strontium-82 and germanium-68 by bombarding rubidium chloride and gallium metal targets respectively with a 100 MeV proton beam, 230 uA average current. Rastering the proton beam is necessary to distribute beam power deposited as heat in the target and allow for higher average beam current for isotope production. We currently use a single circle raster pattern with constant amplitude and frequency. In this paper, we demonstrate two different varying amplitude raster patterns (concentric circle and spiral) to achieve uniform target coverage and expose more target volume to beam heating. In this proof-of-principle experiment, we compare beam spot uniformity measured by irradiating films and foils for both raster patterns.
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TUPWI042	Initial Results from Streaked Low-energy Ultra-fast Electron Diffraction System	electron, gun, simulation, diagnostics	2339
	J.J. Hartzell, R.B. Agustsson, S. Boucher, L. Faillace, A.V. Smirnov RadiaBeam, Santa Monica, California, USA P. Musumeci, E.W. Threlkeld UCLA, Los Angeles, USA
	RadiaBeam, in collaboration with UCLA, is developing an inexpensive, low-energy, ultra-fast, streaked electron diffraction (S-UED) system which allows one to reconstruct a single ultrafast event with a single pulse of electrons using and RF deflector. The high-frequency (GHz), high voltage, phase-locked RF field in the deflector enables temporal resolution of atomic events as fine as sub-100 fs. In this paper, we present an overview of the system being developed and the initial experimental results. We also discuss the challenges based on our design of a UED system that incorporates a novel, high-resolution dielectric-loaded RF deflector and a solid-state X-band amplifier.
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TUPWI048	Experimental Demonstration of an Interaction Region Beam Waist Position Knob for Luminosity Leveling	luminosity, optics, controls, detector	2357
	Y. Hao, Y. Luo, A. Marusic, G. Robert-Demolaize, X. Shen BNL, Upton, Long Island, New York, USA M. Bai FZJ, Jülich, Germany Z. Duan IHEP, Beijing, People's Republic of China
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In this paper, we report on the experimental implementation of the model-dependent control of the interaction region beam waist position (s* knob) at the Relativistic Heavy Ion Collider (RHIC). The s* adjustment provides an alternative way of controlling the luminosity and is the only known method to control the luminosity and to reduce the pinch effect of the future eRHIC. We first demonstrate the effectiveness of the s* knob in luminosity controlling and its application in the future electron ion collider, eRHIC, followed by details of the experimental demonstration of such knob in RHIC.
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WEXB1	Coherent Synchrotron Radiation in Energy Recovery Linacs	FEL, electron, linac, dipole	2387
	C.C. Hall, S. Biedron, A.L. Edelen, S.V. Milton CSU, Fort Collins, Colorado, USA S.V. Benson, D. Douglas, R. Li, C. Tennant JLab, Newport News, Virginia, USA B.E. Carlsten LANL, Los Alamos, New Mexico, USA
	Collective beam effects, including coherent synchrotron radiation (CSR), have been studied on free-electron lasers (FELs). Here we will discuss a particular case of the CSR effects, that in energy-recovery linacs (ERLs). Special consideration is given to these machines because of their high average beam power and the architecture of the machine for energy recovery forces extreme bends. A recent study conducted on the JLab IR FEL looked at how CSR impacts both average energy and the energy spectrum of the beam. Such studies are important, both broadly, to the understanding of CSR and more specifically for a number of proposed ERL projects. A few proposed examples include the MEIC bunched beam cooler ERL design and ERL FELs for potential lithography purposes that would operate in the EUV range.
	Slides WEXB1 [16.383 MB]
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WEXB3	Realization of Pseudo Single Bunch Operation with Adjustable Frequency	kicker, operation, timing, resonance	2396
	C. Sun, G.J. Portmann, D. Robin, C. Steier LBNL, Berkeley, California, USA
	Funding: This work is supported by the Director Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 We present the concept and results of pseudo-single-bunch (PSB) operation–a new operational mode at the advanced light source–that can greatly expand the capabilities of synchrotron light sources to carry out dynamics and time-of-flight experiments. In PSB operation, a single electron bunch is displaced transversely from the other electron bunches using a short-pulse, high-repetition-rate kicker magnet. Experiments that require light emitted only from a single bunch can stop the light emitted from the other bunches using a collimator. Other beam lines will only see a small reduction in flux due to the displaced bunch. As a result, PSB allows to run timing experiments during the multibunch operation. Furthermore, the time spacing of PSB pulses can be adjusted from milliseconds to microseconds with a novel “kick-and-cancel” scheme, which can significantly alleviate complications of using high-power choppers and substantially reduce the rate of sample damage.
	Slides WEXB3 [128.794 MB]
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WEYB1	Benchmarking and Application of Space Charge Codes for Rings	space-charge, simulation, resonance, lattice	2402
	S. Machida STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	This presentation should present an overview of efforts for benchmarking and application of space charge codes for rings. After briefly recalling the historical background of the simulation efforts of space charge effects in rings, we will overview the present benchmarking efforts against experimental results.
	Slides WEYB1 [6.541 MB]
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WEAB2	Beam and Spin Dynamics for Storage Ring Based EDM Search	dipole, simulation, storage-ring, resonance	2454
	A. Lehrach FZJ, Jülich, Germany
	Funding: On behalf of the JEDI collaboration and JARA-FAME (Jülich Aachen Research Alliance) Permanent EDMs (electric dipole moment) of fundamental particles violate both time invariance T and parity P. Assuming the CPT theorem this implies CP violation. The Standard Model (SM) predicts non-vanishing EDMs, their magnitudes, however, are expected to be unobservably small with current techniques. Hence, the discovery of a non-zero EDM would be a signal for “new physics”. As a first step towards EDM searches of charged particles in storage rings, R&D work at the Cooler Synchrotron COSY is pursued. On a longer time scale, the design and construction of a dedicated storage ring will be carried out. Spin-tracking simulations are absolutely crucial to explore the feasibility of the planned storage ring EDM experiments and to investigate systematic limitations. For a detailed study during the storage and buildup of the EDM signal, one needs to track a large sample of particles for billions of turns. Benchmarking experiments are performed at the Cooler Synchrotron COSY to check and to further improve the simulation tools and prototype accelerator components are tested. Finally, the layout of a dedicated storage ring has to be optimized by a full simulation of spin motion.
	Slides WEAB2 [1.459 MB]
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WEAD1	Commissioning and Recent Experimental Results at the Argonne Wakefield Accelerator Facility (AWA)	wakefield, electron, acceleration, laser	2472
	M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, J.H. Shao, D. Wang, C. Whiteford, E.E. Wisniewski ANL, Argonne, Illinois, USA S.P. Antipov, C.-J. Jing, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA G. Ha POSTECH, Pohang, Kyungbuk, Republic of Korea J.H. Shao, D. Wang TUB, Beijing, People's Republic of China
	Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357. The commissioning of the upgraded AWA facility has been recently completed. The L-band electron gun has been fully commissioned and has been successfully operated with its Cesium Telluride photocathode at a gradient of 80 MV/m. Single bunches of up to 100 nC, and bunch trains of up to 32 bunches have been generated. The six new pi-mode accelerating cavities bring the beam energy to 75 MeV. Initial measurements of the beam parameters have been performed. This intense beam has been used to drive high gradient wakefields in several structures. A second beamline provides electron bunches to probe the wakefields generated by the intense drive beam. One of the main goals of the facility is to generate short RF pulses with GW power levels, corresponding to accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure.
	Slides WEAD1 [2.091 MB]
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WEPWA005	Simulations Study for Self-Modulation Experiment at PITZ	plasma, electron, wakefield, simulation	2496
	G. Pathak, F.J. Grüner Uni HH, Hamburg, Germany C. Benedetti, C.B. Schroeder LBNL, Berkeley, California, USA M. Groß, F. Stephan DESY Zeuthen, Zeuthen, Germany A. Martinez de la Ossa, T.J. Mehrling, J. Osterhoff DESY, Hamburg, Germany
	Self-modulation (SM) of proton beams in plasma has recently gained interest in context with the ongoing PWFA experiment of the AWAKE collaboration at CERN. Instrumental for that experiment is the SM of a proton beam to generate bunchlets for resonant wave excitation and efficient acceleration. A fundamental understanding of the underlying physics is vital, and hence an independent experiment has been set up at the beamline of the Photo Injector Test Facility at DESY, Zeuthen Site (PITZ), to study the SM of electron beams in a plasma. This contribution presents simulation results on SM experiments at PITZ using the particle-in-cell code HiPACE. The simulation study is crucial to optimize the beam and plasma parameters for the experiment. Of particular interest is the energy modulation imprinted onto the beam by means of the generated wakefields in the plasma. With the support of simulations the observation of this information in the experiment can be used to deduce key properties of the accelerating electric fields such as their magnitude and their phase velocity, both of significant importance for the design of self-modulated plasma-based acceleration experiments.
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WEPWA006	Laser Propagation Effects During Photoionization of Meter Scale Rubidium Vapor Source	laser, plasma, proton, wakefield	2499
	J.T. Moody, F. Batsch, A. Joulaei, P. Muggli, E. Öz MPI-P, München, Germany N. Berti, J. Kasparian University of Geneva, GAP Biophotonics, Carouge, Switzerland
	The baseline AWAKE experiment requires a 10 meter long plasma source with a density of 10¹⁵ cm􀀀^-3 and a density uniformity of 0.2%. To produce this plasma, a temperature stabilized rubidium vapor source is photoionized by a terawatt peak power laser pulse. In this paper we describe the laser pulse evolution within the plasma source including the dispersive, diffractive, and photoionization effects on the laser pulse. These calculations will be experimentally investigated in a meter long heat pipe oven using scaled laser parameters.
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WEPWA007	The AWAKE Proton-driven Plasma Wakefield Experiment at CERN	plasma, electron, wakefield, injection	2502
	P. Muggli MPI-P, München, Germany
	Funding: For the AWAKE collaboration The AWAKE experiment at CERN * aims at studying plasma wakefield generation and acceleration driven by proton bunches. The first experiments will focus on the self-modulation instability of the long (~12cm, rms) proton bunch in the plasma. This instability is used to transform the incoming bunch into a train of short bunches with a period approximately equal to the plasma wavelength, ~1.2mm at a nominal plasma electron density of 7·10¹⁴/cc. These experiments are planned for the end of 2016. Later, low energy (~15MeV) electrons will be externally injected to sample the wakefields and be accelerated beyond 1GeV. The main goals of the experiment will be summarized and the progress with the plasma source, beam diagnostics and injection method will be presented. * AWAKE Collaboration, Plasma Phys. Control. Fusion 56 084013 (2014)
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WEPWA014	Low Temperature Properties of 20 K Cooled Test Cavity for C-band 2.6-cell Photocathode RF Gun	cavity, cryogenics, gun, resonance	2519
	T. Tanaka, M. Inagaki, K. Nakao, K. Nogami, T. Sakai LEBRA, Funabashi, Japan M.K. Fukuda, T. Takatomi, J. Urakawa, M. Yoshida KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan T.S. Shintomi Nihon University, Tokyo, Japan
	Funding: Work supported by the Photon and Quantum Basic Research Coordinated Development Program of the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT). A cryogenic C-band 2.6-cell photocathode RF gun, which operates at 20 K, is under development at Nihon University for future possibility of use in a compact linac-driven X-ray source. The cavity material is 6N8 high purity copper, the RRR of which being expected to be higher than 3000. A 2.6-cell pi-mode test cavity was fabricated for investigation of the properties under low temperature of 20 K. Ultraprecision machining and diffusion bonding of the cavity were carried out in KEK. The operating frequency of the RF gun cavity is 5712 MHz. The machining dimensions of the test cavity were determined by taking into account the contraction of copper from room temperature to 20 K by approximately 0.33 %. The resonant frequency observed at around 21 K was 5711.761 MHz, which is 185 kHz higher than the expected value that was deduced from the resonant frequency obtained at 23.5 degree C in vacuum and the linear expansion coefficient data for OFC copper by NIST. The unloaded Q-value of 64500 obtained at 21 K is in agreement with the SUPERFISH calculation when the surface resistance of the RRR=3000 copper was specified with taking the anomalous skin effect into account. T. Tanaka et al., Proceedings of IPAC2014, 658-660, http://accelconf.web.cern.ch/AccelConf /IPAC2014/papers/mopri030.pdf ** http://cryogenics.nist.gov/MPropsMAY/OFHC%20Copper/OFHC_Copper_rev.htm
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WEPWA018	Re-acceleration of Ultra Cold Muon in J-PARC MLF	acceleration, linac, rfq, proton	2532
	M. Yoshida, F. Naito KEK, Ibaraki, Japan S. Artikova, Y. Kondo JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan N. Hayashizaki RLNR, Tokyo, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan K. Torikai Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan
	Funding: MEXT KAKENHI Grant Number 6108718 The ultra cold muon beam by two-photon laser resonant ionization of muonium atoms is unique way to obtain very low emittance muon beam. Its muon source is a surface muon from the muon target in MLF where one percent proton beam from J-PARC RCS is reacted. In close collaboration with the Muon Science Es- tablishment (MUSE) at Material and Life science experi- mental Facility (MLF) of the Japan Proton Accelerator Re- search Complex (J-PARC), we are developing the reacceleration system of the ultra cold muon beam. Its optimum accelerating structure is similar to a proton accelerator in low beta part and an electron accelerator in high beta part. Further the muon bunch is only two bunch corresponding to the bunch structure of the J-PARC RCS. Thus we are testing the dielectric transmission line accelerator based on the photoconductive switch as the altenative acceleration method.
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WEPWA023	Development of Muon LINAC for the Muon g-2/EDM Experiment at J-PARC	acceleration, target, rfq, cavity	2541
	M. Otani, Y. Fukao, T. Mibe, N. Saito, M. Yoshida KEK, Tsukuba, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan R. Kitamura University of Tokyo, Tokyo, Japan Y. Kondo JAEA, Ibaraki-ken, Japan
	The muon anomalous magnetic moment (g-2) and electric dipole moment (EDM) are one of the effective paths to beyond Standard Model of elementary particle physics. The E34 experiment aims to measure g-2 with a precision of 0.1 ppm and search EDM with a sensitivity to 10-21 e*cm with high intensity proton driver at J-PARC and a newly developed novel technique of the ultra-cold muon beam. The ultra-cold muons, which are generated from surface muons by the thermal muonium production and laser ionization, are accelerated to 300 MeV/c by muon linear accelerator. The muon LINAC consists of RFQ and following three types of the RF cavities. The muon acceleration to this energy will be the first case in the world. This poster reports about status of the initial acceleration test with RFQ and the development of the RF cavities, especially for the middle beta section.
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WEPWA025	RF Acceleration of Ions Produced by Short Pulse Laser	ion, laser, rfq, 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, ion-source, electron, operation	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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WEPWA032	CsK2Sb Growth Studies: Towards High Quantum Efficiency and Smooth Surfaces	cathode, simulation, emittance, detector	2566
	S.G. Schubert, M. Gaowei, J. Sinsheimer, J. Smedley BNL, Upton, Long Island, New York, USA Z. Ding, E.M. Muller SBU, Stony Brook, New York, USA J. Kühn HZB, Berlin, Germany H.A. Padmore, J.J. Wong LBNL, Berkeley, California, USA J. Xie ANL, Argonne, Illinois, USA
	Funding: This work was supported by the US DOE, under Contracts DE-AC02-05CH11231, DE-AC02-98CH10886, KC0407-ALSJNT-I0013, DE-FG02-12ER41837 and the German BMBF, Helmholtz-Association and Land Berlin. The properties of CsK2Sb, make this material an ideal candidate as photocathode for electron injector use. Producing photocathodes with quantum efficiencies with 7% and greater at 532 nm poses no challenge, nevertheless the traditional growth mechanisms, which are based on a sequential deposition of Antimony, Potassium and Cesium at a temperature gradient yield a rough surface with a rms roughness in the range of 25 nm. Surface roughness’s in this region impacts the emittance. At an accelerating field of 3 MV/m an rms surface roughness of 25 nm is the dominant effect on emittance and will limit injector performance. Studies are performed to optimize roughness. Various growth procedures are exploited and the surface roughness compared.
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WEPWA035	Initial EEX-based Bunch Shaping Experiment Results at the Argonne Wakefield Accelerator Facility	dipole, simulation, cavity, emittance	2575
	G. Ha, M.-H. Cho, W. Namkung POSTECH, Pohang, Kyungbuk, Republic of Korea M.E. Conde, D.S. Doran, W. Gai, G. Ha, C.-J. Jing, K.-J. Kim, W. Liu, J.G. Power, Y.-E. Sun, C. Whiteford, E.E. Wisniewski, A. Zholents ANL, Argonne, Illinois, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA P. Piot Fermilab, Batavia, Illinois, USA
	Funding: This work is partly supported by POSTECH BK²¹⁺ and Argonne National Laboratory A program is under development at Argonne National Laboratory to use an emittance exchange (EEX) beamline to perform longitudinal bunch shaping (LBS). The double dog-leg EEX beamline was recently installed at the Argonne Wakefield Accelerator (AWA) and the goals of the proof-of-principle experiment are to demonstrate LBS and characterize its deformations from the ideal shape due to higher-order and collective effects. The LBS beamline at the AWA consists of insert-able transverse masks mounted on an actuator and four quadrupoles (to manipulate the transverse phase space) before the EEX beamline, which consists of two identical dog-legs and a deflecting cavity. The mask and input beam parameters are varied during the experiment to explore the shaping capability and clarify the deformation sources and their mitigation. Progress on the commissioning of the LBS beamline, initial experimental data and benchmarks to GPT simulations will be presented.
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WEPWA044	The Alignment of the MICE Tracker Detectors	alignment, emittance, detector, scattering	2597
	M.A. Uchida Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	The Muon Ionization Cooling experiment (MICE) has been designed to demonstrate the reduction of the phase-space volume (cooling) occupied by a muon beam using the ionization-cooling technique. This demonstration will be an important step in establishing the feasibility of muon accelerators for particle physics. The emittance of the beam will be measured before and after the cooling cell using a solenoidal spectrometer. Each spectrometer will be instrumented with a high-precision scintillating-fibre tracking detector (Tracker). The Trackers will be immersed in a uniform magnetic field of 4T and will measure the normalised emittance reduction with a precision of 0.1%. A thorough knowledge of the alignment of the Trackers is essential for this accuracy to be achieved. The Trackers are aligned: mechanically inside the spectrometer solenoids, with respect to the MICE experimental hall, to one another, and to the magnetic and beam axes. These methods are described here.
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WEPWA049	Low Energy Beam Tracking Under Scattering for a Cold Electron Source in Manchester	electron, scattering, emittance, extraction	2615
	R.B. Appleby, W. Bertsche, O. Mete, G.X. Xia UMAN, Manchester, United Kingdom M.A. Harvey, M. Jones, A.J. Murray The University of Manchester, The Photon Science Institute, Manchester, United Kingdom B. Kyle University of Manchester, Manchester, United Kingdom
	High quality electron beams, with high spatial and temporal resolution, have an important use in electron diffraction experiments to probe and study the constituents of matter. A cold electron source is being developed based on electron ionisation from an atom cloud trapped by using AC magneto-optical methods in the University of Manchester. The technique will produce bunches of electrons well suited for high precision and single shot electron diffraction. In this paper issues of modelling at low energies for this state of art electron source with very low energy spread are presented, with a focus on newly developed tools to model the scattering in the meshes used to support the extraction electric fields. The dependence on emittance growth on mesh wire thickness is studied.
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WEPWA067	Acoustic Breakdown Localization in RF Cavities	cavity, simulation, timing, diagnostics	2658
	P.G. Lane, P. Snopok, Y. Torun Illinois Institute of Technology, Chicago, Illinois, USA E. Behnke, I.Y. Levine Indiana University South Bend, South Bend, USA D.W. Peterson Fermilab, Batavia, Illinois, USA
	Funding: US Department of Energy Current designs for muon cooling channels require high-gradient RF cavities to be placed in solenoidal magnetic fields in order to contain muons with large transverse emittances. It has been found that doing so reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields it would be helpful to have a diagnostic tool which can detect breakdown and localize the source of the breakdown inside the cavity. We report here on acoustic simulations and comparisons with experimental acoustic data of breakdown from several RF cavities. Included in this analysis are our most recent results from attempting to localize breakdown using these data.
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WEPJE002	Photoinjector Improvement and Control by Surface Acoustic Waves	electron, photon, controls, linac	2678
	R.P. Johnson Muons, Inc, Illinois, USA A. Afanasev, C.E. Korman GWU, Washington, USA
	A new technique is being developed to enhance the efficiency of photocathodes used for electron sources to improve emission capabilities of electron sources, such as bunch charge and average current. The proposed technique is based on the use of surface acoustical waves (SAW) generated on the piezoelectric surface of a GaAs photocathode. The generation of SAW on piezoelectric substrates is known to produce strong piezoelectric fields that propagate on the surface of the material. These fields can significantly suppress recombination effects and result in enhanced quantum efficiency of photoemission. Experimental measurements of photoemission quantum efficiency will be done on semiconductors used as photocathode materials (e.g., GaAs) in presence of SAW with varied parameters. The experimental results will be used as input for physics modeling that will provide a basis for design of operational SAW-enhanced photocathodes. While the improved quantum efficiency and parameter control expected from the use of SAW will be useful for many research devices and accelerators, the commercialization of such a widespread field as electron microscopy is compelling.
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WEPJE006	Dielectric Wakefield Accelerator Experiments at ATF	wakefield, electron, dipole, controls	2681
	D.Y. Shchegolkov, E.I. Simakov LANL, Los Alamos, New Mexico, USA S.P. Antipov Euclid TechLabs, LLC, Solon, Ohio, USA M.G. Fedurin BNL, Upton, Long Island, New York, USA
	Funding: This work is supported by the U.S. Department of Energy through the Laboratory Directed Research and Development (LDRD) program at Los Alamos National Laboratory. Dielectric wakefield acceleration (DWA) presents us with means to achieve the accelerating gradient high above the limits of conventional accelerators. In a typical DWA scheme a higher energy lower charge main bunch is accelerated in the wakefield produced by a preceding lower energy higher charge drive bunch inside of a hollow metal-encapsulated dielectric tube. To make use of as much energy of the drive bunch as possible, it is highly important that all parts of it decelerate uniformly. Close to uniform drive bunch deceleration can be achieved if its current is properly shaped.* At Accelerator Test Facility (ATF) at BNL we shaped the current of a chirped electron beam with an adjustable mask placed inside of the highly dispersive region in the magnetic dogleg. We passed the shaped beam current through a quartz tube and observed the beam particles’ energy modulation at the tube’s output with a spectrometer. By tuning the mask we were able to control the beam energy modulation and thus the wakefield profile in the tube. * B. Jiang, C. Jing, P. Schoessow, J. Power, and W. Gai, PRSTAB 15, 011301 (2012).
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WEPJE016	INTENSE MUON BEAMS FROM THE CSNS SPALLATION TARGET	target, solenoid, proton, neutron	2708
	Y. Bao, G.G. Hanson UCR, Riverside, California, USA
	Intense muon beams are useful for a wide range of physics experiments. Currently most of the muon beams are produced by protons hitting thin targets sitting upstream of spallation neutron targets. The intensity of the muons is greatly limited by the small thickness of the muon targets, which are intended to have minimum impact on the proton beams. When the majority of the proton beam hits the spallation target, a large number of pions/muons are produced. After being captured in a solenoidal magnetic field, a high intensity muon beam can be produced. In this paper we take the Chinese Spallation Neutron Source (CSNS) target as an example and investigate the production of high intensity muon beams. Two possibilities are presented in this paper: an upstream collection of surface muons and a downstream collection of pions which is followed by a decay and compress channel to obtain a high intensity muon beam. Simulations show both methods can reach high intensities which could significantly increase the statistics of many experiments.
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WEPJE020	The Two Beam Acceleration Staging Experiment at Argonne Wakefield Accelerator Facility	acceleration, wakefield, timing, kicker	2714
	C.-J. Jing, S.P. Antipov, A. Kanareykin, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, J.H. Shao, D. Wang, E.E. Wisniewski ANL, Argonne, Illinois, USA J. Shi TUB, Beijing, People's Republic of China
	Funding: DoE SBIR Program Staging, defined as the accelerated bunch in a wakefield accelerator continues to gain energy from sequential drive bunches, is one of the most critical technologies, yet be demonstrated, required to achieve high energy. Using the Two Beam Acceleration (TBA) beamline at Argonne Wakefield Accelerator facility, we will perform a staging experiment using two X-band TBA units. The experiment is planned to conduct in steps. We report on the most recent progress.
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WEPJE025	Phase Space Density as a Measure of Cooling Performance for the International Muon Ionization Cooling Experiment	emittance, simulation, luminosity, scattering	2726
	J.S. Berg 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 International Muon Ionization Cooling Experiment (MICE)* is an experiment to demonstrate ionization cooling of a muon beam in a beamline that shares characteristics with one that might be used for a muon collider or neutrino factory. I describe a way to quantify cooling performance by examining the phase space density of muons, and determining how much that density increases. This contrasts with the more common methods that rely on the covariance matrix and compute emittances from that. I discuss why a direct measure of phase space density might be preferable to a covariance matrix method. I apply this technique to an early proposal for the MICE final step beamline. I discuss how matching impacts the measured performance. * http://mice.iit.edu/ I am not a MICE collaboration member, and nothing herein should be construed as representing the work or views of the collaboration.
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WEPJE027	Partial Return Yoke for MICE Step IV and Final Step	solenoid, shielding, simulation, instrumentation	2732
	H. Witte, J.S. Berg, S.R. Plate BNL, Upton, Long Island, New York, USA A.D. Bross Fermilab, Batavia, Illinois, USA J.S. Tarrant STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. This paper reports on the progress of the design and construction of a retro-fitted return yoke for the international Muon Ionization Cooling Experiment (MICE). MICE is a proof-of-principle experiment aiming to demonstrate ionization cooling experimentally. In earlier studies we outlined how a partial return yoke can be used to mitigate stray magnetic field in the experimental hall; we report on the progress of the construction of the partial return yoke for MICE Step IV. We also discuss an extension of the Partial Return Yoke for the final step of MICE; we show simulation results of the expected performance.
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WEPMA030	Design and Characterization of Permanent Magnetic Solenoids for REGAE	solenoid, emittance, electron, simulation	2822
	M. Hachmann, K. Flöttmann, T. Gehrke, F. Mayet DESY, Hamburg, Germany
	REGAE is a small electron linear accelerator at DESY. In order to focus short and low charged electron bunches down to a few micrometre permanent magnetic solenoids were designed, assembled and field measurements were done. Due to a shortage of space close to the operation area an in-vacuum solution has been chosen. Furthermore a tworing design made of wedges has been preferred in terms of beam dynamic issues. To keep the field quality of a piecewise built magnet still high a sorting algorithm for the wedge arrangement has been developed and used for the construction of the magnets. The magnetic field of these solenoids has been measured with high precision and has been compared to the simulated magnetic field.
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WEPMA040	Magnet Studies for the Accelerator FLUTE at KIT	dipole, linac, multipole, simulation	2849
	S. Hillenbrand, A. Bernhard, A.-S. Müller, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Sauter, S. Schott, M. Schuh, S. Schulz, M. Weber, P. Wesolowski, C. Widmann KIT, Karlsruhe, Germany
	At KIT we are currently constructing the compact linear accelerator FLUTE (Ferninfrarot Linac Und Test Experiment). This 41 MeV machine is aimed at accelerator physics and synchrotron radiation research, using ultra-short electron bunches. The electrons are generated at a photo-cathode using picosecond long UV laser pulses. A magnetic chicane is used to compress the bunches longitudinally to a few femtoseconds. This contribution describes both the magnet design, in particular the optimization of the chicane dipoles based on finite element method (FEM) simulations, as well as the implementation of a magnet measurement system.
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WEPMA054	A Disturbance-Observer-based Controller for LLRF Systems	controls, LLRF, beam-loading, cavity	2895
	F. Qiu, D.A. Arakawa, Y. Honda, H. Katagiri, T. Matsumoto, S. Michizono, T. Miura, T. Obina KEK, Ibaraki, Japan S.B. Wibowo Sokendai, Ibaraki, Japan
	Digital low-level radio frequency (LLRFs) systems have been developed and evaluated in the compact energy recovery linac (cERL) at KEK. The required RF stabilities are 0.1% rms in amplitude and 0.1° rms in phase. These requirements are satisfied by applying digital LLRF systems. To further enhance the control system and make it robust to disturbances such as large power supply (PS) ripples and high-intensity beams, we have designed and developed a disturbance observer (DOB)-based control method. This method utilizes the RF system model, which can be acquired using modern system identification methods. Experiments show that the proposed DOB-based controller is more effective in the presence of high disturbances compared with the conventional proportional and integral (PI) controller. In this paper, we present the preliminary results based on the experiments with DOB-based controller.
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WEPMN008	Material Test of Proton Beam Window for CSNS	proton, target, neutron, operation	2927
	H.J. Wang, L. Kang, H. Qu, L. Wu, D.H. Zhu IHEP, Beijing, People's Republic of China
	The proton beam window (PBW) is one of the key devices of China Spallation Neutron Source (CSNS). Material selection is of particular importance. A5083-O was selected in the previous work, and recently the material tests were done. The tests showed the material has good microstructure, physical and mechanical performance. Creep lifetime was analyzed based on the creep test. All the experiment showed the selected material is qualified.
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WEPMN015	Dark Current Imaging Experiment in an L-band RF Gun	cathode, solenoid, gun, electron	2952
	J.H. Shao, H.B. Chen, J. Shi, D. Wang TUB, Beijing, People's Republic of China S.P. Antipov, S.V. Baryshev, C.-J. Jing, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, D.S. Doran, W. Gai, W. Liu, J.G. Power, C. Whiteford, E.E. Wisniewski ANL, Argonne, Illinois, USA F.Y. Wang, L. Xiao SLAC, Menlo Park, California, USA
	The localized high electric field enhancement or low work function is the trigger for strong field emission, which however has yet been well experimentally studied. Using an L-band photocathode gun test stand at Argonne Wakefield Accelerator Facility (AWA), we’ve constructed an imaging beam line to observe field emission current from predefined emitters on cathode. Preliminary experiment results are present. Future plan is discussed.
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WEPMN016	Observation of Dark Current Dependence on Stored Energy in an L-Band RF Gun	cathode, gun, solenoid, simulation	2956
	J.H. Shao, H.B. Chen, J. Shi, D. Wang TUB, Beijing, People's Republic of China S.P. Antipov, S.V. Baryshev, C.-J. Jing, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, D.S. Doran, W. Gai, W. Liu, J.G. Power, C. Whiteford, E.E. Wisniewski ANL, Argonne, Illinois, USA F.Y. Wang, L. Xiao SLAC, Menlo Park, California, USA
	A pin cathode has been installed into an L-band photocathode gun to study the influence of stored energy on field emission. The stored energy was varied by tuning the recess of the cathode in order to have the same E-field on the cathode tip. We have observed 5 times difference of dark current level at the same E-field, while by varying the stored energy by three fold. Dynamics study reveals the difference is not caused by transmission, but by emission process itself. We'll present experiment results and discuss possible mechanisms about the phenomena.
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WEPMN017	High Power RF Radiation at W-band Based on Wakefields Excited by Intense Electron Beam	wakefield, electron, simulation, radiation	2960
	D. Wang, C.-X. Tang TUB, Beijing, People's Republic of China S.P. Antipov, C.-J. Jing, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, E.E. Wisniewski ANL, Argonne, Illinois, USA
	We report the experiment design and preliminary results on high power RF generation at W-band based on coherent wakefields from the metallic periodic structure of 91 GHz PETS (power extraction and transfer structure), excited by intense electron beam at the Argonne Wakefield Accelerator (AWA) facility. The recently output RF power is 0.7 MW, with 67 MeV, 1.4 nC single electron beam going through the structure. The RF pulse length is 3.4 ns. We measure the energy loss of electron beam as reference to the RF generation, which agrees well with the simulation results. Next run is to increase the output RF power with higher charge and to excite coherent wakefields with electron bunch train. The output RF peak power is expected to be ~100 MW and the electrical field gradient can reach up to 400 MV/m, with RF pulse duration adjustable from few ns to 30 ns when excited with 5~10 nC charge in a single bunch and up to 32 sub bunches in total.
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Paper

Title

Other Keywords

Page

MOAC1

Awake: the Proof-of-principle R&D Experiment at CERN

proton, laser, electron, plasma

34

P. Muggli
MPI, Muenchen, Germany
M. Bernardini, T. Bohl, C. Bracco, A.C. Butterworth, S. Cipiccia, H. Damerau, S. Döbert, V. Fedosseev, E. Feldbaumer, E. Gschwendtner, W. Höfle, A. Pardons, A.V. Petrenko, J.S. Schmidt, M. Turner, H. Vincke
CERN, Geneva, Switzerland

The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) is a proof-of-principle R&D experiment at CERN. It is the world’s first proton driven plasma wakefield acceleration experiment, using a high-energy proton bunch to drive a plasma wakefield for electron beam acceleration. The AWAKE experiment will be installed in the former CNGS facility and uses the 400 GeV proton beam bunches from the SPS, which will be sent to a plasma source. An electron beam will be injected into the plasma cell to probe the accelerating wakefield. Challenging modifications in the area and new installations are required for AWAKE. First proton beam to the experiment is expected late 2016. The accelerating electron physics will start late 2017. This paper gives an overview of the project from a physics and engineering point of view, it describes the main activities, the milestones, the organizational set-up for the project management and coordination.

Slides MOAC1 [21.632 MB]

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MOPWA009

Channeling Radiation Experiment at Fermilab ASTA

electron, photon, brilliance, detector

95

D. Mihalcea, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
D.R. Edstrom, P. Piot, T. Sen
Fermilab, Batavia, Illinois, USA
W.D. Rush
KU, Lawrence, Kansas, USA

Electron beams with moderate energy ranging from 4 to 50 MeV can be used to produce x-rays through the Channeling Radiation (CR) mechanism. Typically, the x-ray spectrum from these sources extends up to 140 keV and this range covers the demand for most practical applications. The parameters of the electron beam determine the spectral brilliance of the x-ray source. The electron beam produced at the Fermilab new facility Advanced Superconducting Test Accelerator (ASTA) meets the requirements to assemble an experimental high brilliance CR x-ray source. In the first stage of the experiment the energy of the beam is 20 MeV and due to the very low emittance (100 nm) at low bunch charge (20 pC) the expected average brilliance of the x-ray source is 0.8x10⁷ photons/[s-(mm-mrad)²-0.1%BW]. In the second stage of the experiment the beam energy will be increased to 50 MeV and consequently the average brilliance will be 4.8x10⁸ photons/[s-(mm-mrad)²-0.1%BW]. Also, the x-ray spectrum will be extended from about 30 keV to 140 keV.

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MOPWA036

Status of Injection Studies into the Figure-8 Storage Ring

injection, simulation, kicker, ion

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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MOPWA046

Lattice and Beam Dynamics of the Energy Recovery Mode of the Mainz Energy-recovering Superconducting Accelerator MESA

linac, cryomodule, lattice, simulation

220

D. Simon, K. Aulenbacher, R.G. Heine, F. Schlander
IKP, Mainz, Germany

Funding: Work supported by the German Federal Ministry of Education and Research (BMBF) and German Research Foundation (DFG) under the Cluster of Excellence PRISMA.
The mainz energy recovering superconducting accelerator (MESA) is a proposed multi-turn energy recovery linac for particle physics experiments. It will be built at the institute for nuclear physics (KPH) at Mainz University. Because of the multi-turn energy recovery mode there are particular demands at the beam dynamics. We present the current status of the lattice development.

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MOPJE023

3D Computer Simulations of the Ultrarelativistic Beam Dynamics in Super Colliders

simulation, collider, focusing, plasma

326

M.A. Boronina, V.A. Vshivkov
ICM&MG SB RAS, Novosibirsk, Russia
G. Dudnikova
ICT SB RAS, Novosibirsk, Russia

Funding: The work is supported by RFBR Grants 14-01-31088, 14-01-00392, 14-07-00241.
The problem of numerical modeling of beam-beam interaction with high relativistic factor (~10⁴) is considered. We present 3D a self-consistent simulation model based on particle-in-cell method. The mixed Euler-Lagrangian decomposition is used in parallel algorithm for achieving good load balancing and reducing communication cost. Stable regimes of beam dynamics, depending on the beams configuration (beta-function, emittance, energy, currents and relative offset) can be found on the base of the model. In the calculations we used 10⁸ particles on the grid 100x100x100, the number of processors depends highly on the beam shape. The Lomonosov Super Computer and Siberian Supercomputer Centre cluster were used to perform the presented simulations.

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MOPJE044

Beam Dynamics Studies of the ELENA Electrostatic Transfer Lines

quadrupole, antiproton, optics, simulation

385

M.A. Fraser, W. Bartmann, R. Ostojić
CERN, Geneva, Switzerland
D. Barna
University of Tokyo, Tokyo, Japan

The low-energy ELENA ring at the Antiproton Decelerator (AD) facility at CERN will lower the kinetic energy of antiproton beams from 5.3 MeV to 100 keV, significantly increasing the antiproton trapping efficiency at the experiments. The antiprotons from ELENA will be distributed to two experimental areas housing several different experiments through a system of electrostatic transfer lines totalling 90 m in length. A significant optimisation of the electrostatic optical elements (deflectors, quadrupoles, and correctors) has been carried out to improve the beam quality delivered to the experiments and facilitate installation of the beam lines into the AD hall. A general overview of the beam optics is presented, including end-to-end particle tracking and error studies from the extraction point in the ELENA ring to the experiments.

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MOPJE077

Progress on Simulation of Fixed Field Alternating Gradient Accelerators

simulation, closed-orbit, betatron, acceleration

495

S.L. Sheehy
JAI, Oxford, United Kingdom
A. Adelmann
PSI, Villigen PSI, Switzerland
M. Haj Tahar, F. Méot
BNL, Upton, Long Island, New York, USA
Y. Ishi, Y. Kuriyama, Y. Mori, M. Sakamoto, T. Uesugi
Kyoto University, Research Reactor Institute, Osaka, Japan
D.J. Kelliher, S. Machida, C.R. Prior, C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Fixed Field Alternating Gradient accelerators have been realised in recent decades thanks partly to computational power, enabling detailed design and simulation prior to construction. We review the specific challenges of these machines and the range of different codes used to model them including ZGOUBI, OPAL and a number of in-house codes from different institutes. The current status of benchmarking between codes is presented and compared to the results of recent characterisation experiments with a 150 MeV FFAG at KURRI in Japan. Finally, we outline plans toward ever more realistic simulations including space charge, material interactions and more detailed models of various components.

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MOPJE084

Particle-in-cell Simulations of a Plasma Lens at Daresbury Laboratory

plasma, focusing, emittance, simulation

518

K. Hanahoe, O. Mete, G.X. Xia
UMAN, Manchester, United Kingdom
D. Angal-Kalinin, J.K. Jones
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.D.A. Smith
TXUK, Warrington, United Kingdom

Feasibility of a focusing element using the transverse fields provided by a plasma cell was studied numerically. In this paper, an experimental set up is proposed for various beam parameters available from the VELA and CLARA beam lines at Daresbury Laboratory. 2D simulation results from VSim, and expected results from planned measurement stations are presented. Field properties and the advantages and disadvantages of such an instrument compared to conventional focusing elements are discussed.

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MOPMA022

Numerical Analysis of Parasitic Crossing Compensation with Wires in DAΦNE

positron, luminosity, beam-beam-effects, collider

589

A. Valishev
Fermilab, Batavia, Illinois, USA
C. Milardi, M. Zobov
INFN/LNF, Frascati (Roma), Italy
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

Funding: This work was partially supported by the US LARP. The HiLumi LHC Design Study is partially funded by the European Commission Grant Agreement 284404.
Current bearing wire compensators were successfully used in the 2005-2006 running of the DAΦNE collider to mitigate the detrimental effects of parasitic beam-beam interactions. A marked improvement of the positron beam lifetime was observed in machine operation with the KLOE detector. In view of the possible application of wire beam-beam compensators for the High Luminosity LHC upgrade, we revisit the DAΦNE experiments. We use an improved model of the accelerator with the goal to validate the modern simulation tools and provide valuable input for the LHC upgrade project.

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MOPMA049

Development of a Single-pass Amplifier for an Optical Stochastic Cooling Proof-of-principle Experiment at Fermilab's IOTA facility

laser, undulator, radiation, focusing

659

M.B. Andorf, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
V.A. Lebedev, P. Piot
Fermilab, Batavia, Illinois, USA

Optical stochastic cooling (OSC) is a method of beam cooling which is expected to provide cooling rates orders of magnitude larger than ordinary stochastic cooling. Light from an undulator (the pickup) is amplified and fed back onto the particle beam via another undulator (the kicker). Fermilab is currently exploring a possible proof-of-principle experiment of the OSC at the integrable-optics test accelerator (IOTA) ring. To implement effective OSC a good correction of phase distortions in the entire band of the optical amplifier is required. In this contribution we present progress in experimental characterization of phase distortions associated to a Titanium Sapphire crystal laser-gain medium (a possible candidate gain medium for the OSC experiment to be performed at IOTA). We also discuss a possible option for a mid-IR amplifier.

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MOPMN020

Longitudinal Impedance of RHIC

synchrotron, impedance, storage-ring, scattering

746

M. Blaskiewicz, J.M. Brennan, K. Mernick
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 longitudinal impedance of the two RHIC rings has been measured using the effect of potential well distortion on longitudinal Schottky measurements. With Z/n about 5 Ω the impedance of the yellow ring is roughly twice that of the blue ring.

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MOPHA015

Measurement of Momentum Compaction Factor via Depolarizing Resonances at ELSA

resonance, polarization, electron, extraction

811

J.F. Schmidt, W. Hillert, M. Schedler, J.-P. Thiry
ELSA, Bonn, Germany

Funding: DFG
Measuring beam depolarization at energies in close proximity to a depolarizing integer resonance is an established method to determine the beam energy of a circular accelerator. This technique offers high accuracy due to the small resonance widths. Thus, also other accelerator parameters related to beam energy can be measured based on this method. This contribution presents a measurement of the momentum compaction factor with a high precision of 10^-4. It was performed at the 164 m stretcher ring of the Electron Stretcher Facility ELSA at Bonn University, which provides a polarized electron beam of up to 3.2 GeV.

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MOPHA039

A Fast Gated Intensified Camera Setup for Transversal Beam Diagnostics at the ANKA Storage Ring

storage-ring, radiation, synchrotron, bunching

872

P. Schütze, A. Borysenko, E. Hertle, N. Hiller, B. Kehrer, A.-S. Müller, P. Schönfeldt
KIT, Karlsruhe, Germany

ANKA, the synchrotron light source at Karlsruhe Institute of Technology (KIT), can be operated in different modes including the short bunch operation with bunch lengths compressed to a few picoseconds. In this mode, coherent synchrotron radiation (CSR) is emitted leading to beam instabilities. For gaining further insight into those processes, a setup based on a fast gated intensified camera was installed recently at the visible light diagnostics beamline of the ANKA storage ring. The experimental layout consists of an optical setup, which magnifies the image of the beam in the horizontal and demagnifies it in the vertical plane to obtain a projection of the horizontal beam shape, the camera itself and a fast scanning galvanometric mirror that sweeps this image across the sensor. This allows the tracking of the horizontal bunch size and position over many turns. In this paper we present the setup and show first measurement results.

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MOPHA044

Testing a Digital Beam Position Stabilization for the P2-experiment at MESA

FPGA, feedback, controls, electron

888

M. Dehn, K. Aulenbacher, J. Diefenbach, F. Fichtner, R. Herbertz, W. Klag
IKP, Mainz, Germany

Funding: Work supported by the German Federal Ministry of Education and Research (BMBF) and German Research Foundation (DFG) under the Collaborative Research Center 1044 and the Cluster of Excellence "PRISMA"
The Mainz Energy recovering Superconducting Accelerator (MESA) will be built at the institute for nuclear physics at Mainz University. Besides the multi-turn energy recovery mode an external beam mode is foreseen to provide 155 MeV electrons of 85% polarization at 150 μA for parity violating experiments. To achieve the required stability of the main beam parameters a dedicated digital position stabilization is currently developed and tested at the Mainz Microtron (MAMI).

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MOPTY014

An Experimental Study of Higher-Order Modes Excited by High Repetition Rate Electron Beam in an SRF Cavity

HOM, electron, SRF, cavity

965

Y. Gao, J.E. Chen, L.W. Feng, J.K. Hao, S. Huang, L. Lin, K.X. Liu, X. Luo, S.W. Quan, F. Wang, Zh.W. Wang
PKU, Beijing, People's Republic of China

Funding: National Natural Science Foundation of China (No. 11275014)
Higher-order modes (HOMs) excited by electron beam traversing a superconducting rf (SRF) cavity contain lots of information and can be used for intra-cavity electron beam diagnostics. Unlike single bunch, multiple bunches would excite HOMs with a much complicated spectrum. In this paper, we present our recent research on HOMs excited by a high repetition rate electron beam in an SRF cavity. Especially, we focus on the integer multiple frequency peaks in the HOM spectrum, which are determined by the nearest eigen HOM peaks. The experiments were carried out on the DC-SRF photoinjector, which was operated at MHz repetition rate. The results agree well with theoretic analysis.

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MOPTY022

Bunch by Bunch DBPM Processor Development and Preliminary Experiment in SSRF*

injection, hardware, betatron, FPGA

984

Y.B. Leng, Z.C. Chen, L.W. Lai, Y.B. Yan, Y. Yang
SSRF, Shanghai, People's Republic of China

Funding: Work supported by Chinese NSFC11375255.
Digital BPM processor with turn-by-turn capability has been widely used in synchrotron radiation facilities over the world, which is proved to be very useful and powerful for daily operation and linear optics study but not good enough in the case of individual bunch information required. In order to sufficient individual bunch diagnostics requirements a development plan of the next generation DBPM processor with bunch-by-bunch capability has been initiated in SINAP since 2012. The whole development was divided into three steps: a concept processor based on digital oscilloscope IOC, an algorithm prototype processor based on commercial high speed ADC board, and a custom designed dedicated processor. The progress of this work and several preliminary beam experiments will be discussed in this paper.

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MOPTY045

ESS Availability and Reliability Approach

neutron, operation, proton, target

1033

E. Bargalló, K.H. Andersen, R. Andersson, A. De Isusi, A. Nordt, E.J. Pitcher
ESS, Lund, Sweden

Reliability and availability are key metrics for achieving the scientific vision of the ESS. The approach taken to analyze and to improve these metrics in order to achieve the goals is described in this contribution. The methodology used to obtain the requirements considers not only the availability and reliability figures but also the specific needs extracted from users expectations from the neutron source in order to succeed in their experiments. A top-down requirements allocation is being developed at the same time that bottom-up reliability and availability analyses is being performed. The experiments expected at ESS and their needs in terms of neutron beam performance (reliability, availability and quality) are described as well as the tools used to analyze it. Moreover, the consequences of these analyses in the design phase are discussed.

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MOPTY052

Experimental and Simulation Studies of Hydrodynamic Tunneling of Ultra-Relativistic Protons

target, simulation, proton, cavity

1048

F. Burkart, R. Schmidt, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland
A.R. Piriz
Universidad de Castilla-La Mancha, Ciudad Real, Spain
A. Shutov
IPCP, Chernogolovka, Moscow region, Russia
N.A. Tahir
GSI, Darmstadt, Germany

The expected damage due to the release of the full LHC beam energy at a single aperture bottleneck has been studied. These studies have shown that the range of the 7 TeV LHC proton beam is significantly extended compared to that of a single proton due to hydrodynamic tunneling effect. For instance, it was evaluated that the protons and their showers will penetrate up to a length of 25 m in solid carbon compared to a static range of around 3 m. To check the validity of these simulations, beam- target heating experiments using the 440 GeV proton beam generated by the SPS were performed at the HiRadMat test facility at CERN *. Solid copper targets were facially irradiated by the beam and measurements confirmed hydrodynamic tunneling of the protons and their showers. Simulations have been done by running the energy deposition code FLUKA and the 2D hydrodynamic code, BIG2, iteratively. Very good agreement has been found between the simulations and the experimental results ** providing confidence in the validity of the studies for the LHC. This paper presents the simulation studies, the results of a benchmarking experiment, and the detailed target investigations.
* N.A. Tahir et al., Phys. Rev. Special Topics Accel. Beams 15 (2012) 051003.
** R. Schmidt et al., Phys. Plasmas 21 (2014) 080701.

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MOPTY058

Response of Polycrystalline Diamond Particle Detectors Measured with a High Intensity Electron Beam

detector, electron, radiation, beam-losses

1069

O. Stein, F. Burkart, B. Dehning, R. Schmidt, C.B. Sørensen, D. Wollmann
CERN, Geneva, Switzerland
E. Griesmayer
CIVIDEC Instrumentation, Wien, Austria

Comprehensive understanding of beam losses in the LHC is required to ensure full machine protection and efficient operation. The existing BLM system using ionization chambers is not adequate to resolve losses with a time resolution below some 10 us. Ionization chambers are also not adequate to measure very large transient losses, e.g. beam impacting on collimators. Diamond particle detectors with bunch-by-bunch resolution have therefore been used in LHC to measure fast particle losses with a time resolution down to a level of single bunches. Diamond detectors have also successfully been used for material damage studies in other facilities, e.g. HiRadMat at the CERN-SPS. To fully understand their potential, such detectors were characterized with an electron beam at the BTF in LNF INFN Italy, with bunch intensities from 10³ to 10⁹ electrons. The detector response and efficiency has been measured with a 50 Ω and a 1 Ω read-out system. This paper describes the experimental setup and the results of the experiment. In particular, the responses of three samples of 100 um single-crystalline diamond detectors and two samples of 500 um polycrystalline diamond detectors are presented.

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MOPTY060

Pulse Compressor Phase and Amplitude Modulation Based on Iterative Learning Control

klystron, controls, operation, linac

1076

A. Řežaeizadeh, R. Kalt, T. Schilcher
PSI, Villigen PSI, Switzerland
R. Smith
Automatic Control Laboratory, ETH Zurich, Zurich, Switzerland

This paper presents an alternative way to produce flat-topped RF pulses at the pulse compressor output. Flat-topped RF pulses are suitable for multi-bunch operation where it is often required that beams experience the same accelerating gradient. Moreover, the energy gain, in this case, is less sensitive to timing jitters. The proposed approach is based on Iterative Learning Control technique, which iteratively updates the input waveforms, in order to generate the desired output waveforms.

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MOPTY062

The Energy Saving Processes for Utility System in TPS

controls, operation, photon, factory

1082

C.S. Chen, W.S. Chan, J.-C. Chang, Y.C. Chang, Y.-C. Chung, C.W. Hsu, C.Y. Liu, Z.-D. Tsai
NSRRC, Hsinchu, Taiwan

There are more and more non-linear electronic equipments such as inverters using in facility nowadays. These non-linear electronic equipments let us achieve energy saving, but induce other electrical pollution to the whole power grid in contrast. Among these electrical pollutions, electric harmonic is the most common and harmful to power facility. Therefore, how to monitor the electrical noises from these non-linear equipments becomes an important issue. In this article, a set of power quality monitoring system based on FPGA (Field-Programmable Gate Arrays) modules and PAC (Programmable Automatic Controller) has been built because of their programmability and fast processing speed. By using this monitoring system, any abnormality in power system and its spectrum will be recorded thoroughly. On the other hand, the maintainer could follow the trace of noise and then propose a suitable solution to eliminate the electrical interference too.

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MOPWI004

Novel Single Shot Bunch Length Diagnostic using Coherent Diffraction Radiation

electron, radiation, laser, optics

1150

R.B. Fiorito, C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A.G. Shkvarunets
UMD, College Park, Maryland, USA

Funding: European Union’s grant agreement no. 624890 and STFC Cockcroft core grant No. ST/G008248/1; US Office of Naval Research and DOD Joint Technology Office.
Current beam bunch length monitors which measure the spectral content of beam-associated coherent radiation to determine the longitudinal bunch form factor usually require wide bandwidth detection or Fourier transformation of interferometric data and multiple beam pulses. The data must then be Fourier transformed to obtain the bunch length. In this contribution we discuss progress in the development of a novel single shot method that utilizes the frequency integrated angular distribution (AD) of coherent diffraction radiation (CDR) to measure the RMS bunch length directly. We also present simulation results which show how the AD changes with bunch length for several electron beam linacs, where we are planning to test this new method, our single shot measurement technique and plans for comparison to other bunch length monitors.

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MOPWI006

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

ion, vacuum, electron, storage-ring

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

ion, electron, diagnostics, 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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MOPWI015

A Low Time-Dispersion Refractive Optical Transmission Line for Streak Camera Measurements

electron, database, resonance, plasma

1178

J.G. Power, G. Ha
ANL, Argonne, Illinois, USA
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: Work supported by the U.S. Department of Energy office of High Energy Physics.
Streak camera measurements of the charge particle bunch length are limited in resolution due to several factors: (1) the light from the source (optical transition radiation, Cherenkov, synchrotron radiation, etc.); (2) time dispersion introduced in the optical transmission line between the source and the streak camera; and finally (3) the streak camera resolution. The limiting resolution usually arises from the optical transmission line. While an all-reflective transmission line can eliminate dispersion, the system is complicated and expensive. In this paper, we consider how to design a refractive optical transport line to minimize the time dispersion while maximizing the signal. We present a theoretical model of the dispersion, modeling, and measurements of the time dispersion for several different lens materials.

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MOPWI017

Beam Extinction Monitoring in the Mu2e Experiment

proton, target, detector, shielding

1185

E. Prebys, A. Gaponenko, P.H. Kasper
Fermilab, Batavia, Illinois, USA
L.M. Bartoszek
Bartoszek Engineering, Aurora, Illinois, USA

Funding: This work is supported by the US Department of Energy under contract No. De-AC02-07CH11359.
The Mu2e Experiment at Fermilab will search for the conversion of a muon to an electron in the field of an atomic nucleus with unprecedented sensitivity. The experiment requires a beam consisting of proton bunches approximately 200ns FW long, separated by 1.7 microseconds, with no out-of-time protons at the 10^-10 fractional level. The verification of this level of extinction is very challenging. The proposed technique uses a special purpose spectrometer which will observe particles scattered from the production target of the experiment. The acceptance will be limited such that there will be no saturation effects from the in-time beam. The precise level and profile of the out-of-time beam can then be built up statistically, by integrating over many bunches.

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MOPWI032

Analysis of Primary Stripper Foils at SNS by an Electron Beam Foil Test Stand

electron, proton, gun, operation

1230

E.P. Barrowclough, C.S. Feigerle
University of Tennessee, Knoxville, Tennessee, USA
C.F. Luck, M.A. Plum, R.W. Shaw, L.L. Wilson
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
Diamond foils are used at the Spallation Neutron Source (SNS) as the primary strippers of hydride ions. A nanocrystalline diamond film, typically 17x45 mm with an aerial density of 0.35 mg/cm², is deposited on a corrugated silicon substrate by plasma-assisted chemical vapor deposition. After growth, 30 mm of the silicon substrate is etched away, leaving a freestanding diamond foil with a silicon handle that can be inserted into SNS for operation. An electron beam test facility was constructed to study stripper foil degradation and impact on foil lifetime. The electron beam capabilities include: current up to 5 mA, focused spot size of 0.30 mm², and rastering in the x- and y-directions. A 30 keV and 1.6 mA/mm² electron beam deposits the same power density on a diamond foil as a 1.4 MW beam on SNS target. Rastering of the electron beam can expose a similar area of the foil as SNS beams. Experiments were conducted using the foil test stand to study: foil flutter and lifetime; effects of corrugation patterns, aerial densities, crystal size (micro vs. nano), and boron doping; temperature distributions and film emissivity; and conversion rate of nanocrystalline diamond into graphite.

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MOPWI036

Investigation of Continuous Scan Methods for Rapid Data Acquisition

detector, data-acquisition, software, hardware

1243

C.L. Li
East China University of Science and Technology, Shanghai, People's Republic of China
A.M. Kiss
SLAC, Menlo Park, California, USA
W.J. Zhang
University of Saskatchewan, Saskatoon, Canada

It is common practice to perform spatially resolved X ray data acquisition by automatically moving components to discrete locations and then measuring beam intensity with the system at rest. While effective, scanning in this manner can be time consuming, with motors needing to accelerate, move and decelerate at each location before recording data. Information between data points may be missed unless fine grid scans are performed, which accounts for a further increase of scan time. Recent advances in commercial hardware and software enables a continuous scan capability for a wide range of applications, which saves the start and end of step motors. To compare scanning performance, both step and continuous scan modes were examined using the SPEC command language with both commercial and in-house hardware. The advantages and limitations of each are discussed.

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TUXB3

700 kW Main Injector Operations for NOvA at FNAL

booster, proton, operation, electron

1286

P. Adamson
Fermilab, Batavia, Illinois, USA

Following a successful career as an antiproton storage and cooling ring, the Fermilab Recycler was repurposed as a proton stacker as part of the NOvA project, in order to increase the maximum NuMI beam power from 400 kW to 700 kW. Using the Recycler to prepare beam for acceleration in the Main Injector, we have been able to increase the beam power delivered to NuMI to a sustained weekly average in excess of 400 kW and a best hourly average of 482.8 kW. I discuss the commissioning progress to date, and describe the remaining steps along the way to achieving the 700 kW design goal.

Slides TUXB3 [3.401 MB]

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TUYC2

Multi-GeV Plasma Acceleration Results at BELLA

laser, plasma, electron, injection

1319

A.J. Gonsalves, C. Benedetti, S.S. Bulanov, J. Daniels, E. Esarey, C.G.R. Geddes, H.S. Mao, D.E. Mittelberger, K. Nakamura, C.B. Schroeder, C. Tóth, J. van Tilborg
LBNL, Berkeley, California, USA
W. Leemans
UCB, Berkeley, California, USA

Funding: U.S. Department of Energy under Contract No. DE-AC02-05CH11231
Laser-plasma accelerators (LPAs)* are being investigated as a compact driver for light sources and high-energy linear colliders. Recently 2 GeV beams were generated by focusing ≈ 100 J laser pulses onto a gas target**. We report here on the generation of beams with energy up to 4.2 GeV using 16 J of laser pulse energy at the BErkeley Lab Laser Accelerator (BELLA)***. This was achieved by using laser pulses of high spatial and temporal quality coupled to a pre-formed capillary discharge waveguide of length 9 cm. The waveguide (in conjunction with self-guiding) allowed for mitigation of diffraction. High spatial quality (Strehl ratio at focus 0.8±0.1) was achieved using a deformable mirror placed before the focusing optic. The dominant contribution to the non-Gaussian content of the focal spot was the near-field intensity profile. For maximum efficiency high-power femtosecond systems employ super-Gaussian near-field profiles of the form I(r)∝e^-2(r/w^N), where I is the intensity, r is the radial coordinate, w is the spot size, and N is the order. Compared with Gaussian laser pulses where N=2, pulses from the BELLA laser system had N=10. Simulations showed that an increased contribution of self-guiding was required to effectively confine the laser energy for optimum acceleration and mitigation of damage to the capillary waveguide. Through appropriate choice of plasma density electron beams with energy up to 4.2 GeV were observed. In this regime the electron beam angular fluctuations were > 2 mrad rms, caused in part by errors in waveguide alignment and by laser-induced damage to the capillary that introduces plasma asymmetry. Improved alignment of the waveguide and mitigation of capillary damage allowed for reduction in angular fluctuations to 0.6 mrad rms. The electron beams had energy of 2.7±0.1 GeV, charge of 150 pC, and divergence less than 1 mrad.
* E. Esarey, et al., Rev. Mod. Phys. 81, 1229 (2009)
** X. Wang, et al., Nat. Communications 4, 1988 (2013)
*** W. P. Leemans, et al., Phys. Rev. Lett. 113, 245002 (2014)

Slides TUYC2 [13.023 MB]

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TUYC3

Scaling Down Synchronous Acceleration: Recent Results, Current Status, and Future Plans of a Subrelativistic Dielectric Laser Acceleration Project

electron, laser, acceleration, focusing

1325

J.C. McNeur, P. Hommelhoff, M. Kozak, A. Li, N. Schönenberger, A.D. Tafel
University of Erlangen-Nuremberg, Erlangen, Germany

This talk will describe the latest results using laser powered dielectric accelerators. Recent experiments in the US (SLAC) and Europe (MPQ) have fabricated dielectric accelerators powered with optical lasers and used them to accelerate electrons with gradients between 25 and 300 MeV/m. The latest results will be reviewed and prospects and applications for the future will be discussed.

Slides TUYC3 [21.295 MB]

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TUBC1

Recent Progress and Operational Status of the Compact ERL at KEK

laser, operation, quadrupole, beam-losses

1359

S. Sakanaka, M. Adachi, S. Adachi, T. Akagi, M. Akemoto, D.A. Arakawa, S. Araki, S. Asaoka, M. Egi, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, A. Ishii, X.J. Jin, E. Kako, Y. Kamiya, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondou, A. Kosuge, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sasaki, K. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, O. Tanaka, Y. Tanimoto, N. Terunuma, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, J. Urakawa, K. Watanabe, M. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan
E. Cenni
Sokendai, Ibaraki, Japan
R. Hajima, S. Matsuba, M. Mori, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
JAEA, Ibaraki-ken, Japan
J.G. Hwang
KNU, Deagu, Republic of Korea
M. Kuriki
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
Y. Seimiya
HU/AdSM, Higashi-Hiroshima, Japan

Funding: Work supported by the Photon and Quantum Basic Research Coordinated Development Program from the MEXT, and by the MEXT grant for promoting technology for nuclear security.
The Compact Energy Recovery Linac (cERL) is a superconducting test accelerator aimed at establishing technologies for the ERL-based future light source. After its construction during 2009 to 2013, the first CW beams of 20 MeV were successfully transported through the recirculation loop in February 2014*. Then, initial tuning of beams and evaluations of beam properties were carried out. From September to December in 2014, we are constructing a Laser Compton Scattering (LCS) source** which aims at demonstrating technology for the future high-flux quasi-monochromatic gamma-ray source. In the next run of the cERL, which begins at the end of January 2015, we plan such works as an increase in the beam current (from 10 uA to 100 uA), commissioning of the LCS source, and sustained tuning of beams for lower emittance. We will report up-to-date results of these developments.
* N. Nakamura et al., IPAC2014, MOPRO110; S. Sakanaka et al., LINAC14, TUPOL01.
** R. Nagai et al., IPAC2014, WEPRO003.

Slides TUBC1 [2.679 MB]

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TUPWA020

BNL ATF II Beamlines Design

electron, laser, cavity, linac

1445

M.G. Fedurin, Y.C. Jing, D. Stratakis, C. Swinson
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 Brookhaven National Lab. Accelerator Test Facility (BNL ATF) is currently undergoing a major upgrade (ATF-II). Together with a new location and much improved facilities, the ATF will see an upgrade in its major capabilities: electron beam energy and quality and CO2 laser power. The electron beam energy will be increased in stages, first to 100-150 MeV followed by a further increase to 500 MeV. Combined with the planned increase in CO2 laser power (from 1-100 TW), the ATF-II will be a powerful tool for Advanced Accelerator research. A high-brightness electron beam, produced by a photocathode gun, will be accelerated and optionally delivered to multiple beamlines. Besides the energy range (up to a possible 500 MeV in the final stage) the electron beam can be tailored to each experiment with options such as: small transverse beam size (<10 um), flat beam, short bunch length (<100 fs) and, combined short and small bunch options. This report gives a detailed overview of the ATF-II capabilities and beamlines configuration.

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TUPWA029

ARES: Accelerator Research Experiment at SINBAD

electron, cavity, bunching, linac

1469

B. Marchetti, R.W. Aßmann, C. Behrens, R. Brinkmann, U. Dorda, K. Flöttmann, J. Grebenyuk, M. Hüning, Y.C. Nie, H. Schlarb, J. Zhu
DESY, Hamburg, Germany

ARES is a planned linear accelerator for R&D for production of ultra-short electron bunches. It will be hosted at the SINBAD facility, at DESY in Hamburg*. The goal of ARES is to produce low charge (0.2-50pC), ultra-short (from few fs to sub-fs) bunches, with high arrival time stability (less than 10fs) for various applications, such as external injection for Laser Plasma Wake-Field acceleration**. The baseline layout of the accelerator foresees an S-band photo-injector which compresses low charge electron bunches via velocity bunching and accelerates them to 100 MeV energy. In the second stage, it is planned to install a third S-band accelerating cavity to reach 200 MeV as well as two X-band cavities: One for the linearization of the longitudinal phase space (subsequently allowing an improved bunch compression) and another one as a transverse deflecting cavity for longitudinal beam diagnostics. Moreover a magnetic bunch compressor is envisaged allowing to cut out the central slice of the beam*** or hybrid bunch compression.
* R. Assmann et al., TUPME047, Proceedings of IPAC 2014.
** R. Assmann, J. Grebenyuk, TUOBB01, Proceedings of IPAC 2014.
*** P. Emma et al., PRL 92 7 (2004).

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TUPWA045

Further Investigations on the MESA injector

coupling, linac, simulation, space-charge

1515

R.G. Heine, K. Aulenbacher, S. Friederich, C. Matejcek, F. Schlander
IKP, Mainz, Germany

Funding: work supported by the German Federal Ministery of Education and Research under the Cluster of Excellence "PRISMA"
The MESA ERL to be build at Mainz in the next years is a multi turn recirculating linac with beam currents of up to 10 mA. The dynamic range of the beam currents demanded by the experiments is of at least two orders of magnitude. This is a special challenge for the layout design of an injector. In this paper we present the current status of the design of the injector linac called MAMBO (MilliAMpereBOoster).

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TUPWA054

The FERMI Seeded FEL Facility: Operational Experience and Future Perspectives

FEL, laser, electron, operation

1538

M. Svandrlik, E. Allaria, L. Badano, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, P. Cinquegrana, M. Coreno, R. Cucini, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, P. Finetti, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, L. Giannessi, F. Iazzourene, M. Kiskinova, S. Krecic, M. Lonza, N. Mahne, C. Masciovecchio, M. Milloch, F. Parmigiani, G. Penco, L. Pivetta, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, E. Roussel, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

FERMI is the seeded FEL user facility in Trieste, Italy, producing photons from the VUV to the soft X-rays with a high degree of coherence and spectral stability. Both FEL lines, FEL-1 and FEL-2, are now available for users, down to the shortest wavelength of 4 nm. We will report on the completion of the commissioning of the high energy FEL line, FEL-2, and on the operational experience for users, in particular those requiring specific FEL configurations, like two-colour experiments. We will also give a perspective on the improvements and upgrades which have been triggered by our experience and are aiming to maintain as well as to constantly improve the performance of the facility for our user community.

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TUPWA058

Study of a C-band Harmonic RF System to Optimize the RF Bunch Compression Process of the SPARC Beam

cavity, gun, linac, emittance

1552

A. Gallo, D. Alesini, M. Bellaveglia, M. Ferrario
INFN/LNF, Frascati (Roma), Italy
A. Bacci, V. Petrillo, A.R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
F. Cardelli, L. Piersanti
INFN-Roma1, Rome, Italy
B. Marchetti
DESY, Hamburg, Germany
M. Rossetti Conti
Universita' degli Studi di Milano & INFN, Milano, Italy

The SPARC linac at the INFN Frascati Labs is a high brilliance electron source with a wide scientific program including production of THz and Thomson backscattering radiation, FEL studies and plasma wave acceleration experiments. The linac is based on S-band RF and consists in an RF Gun followed by 3 accelerating structures, while an energy upgrade based on 2 C-band accelerating structures is ready to be implemented. Short bunches are ordinarily produced by using the linear RF bunch compression concept. A harmonic RF structure interposed between the Gun and the 1st accelerating structure can be used to optimize the RF compression by a longitudinal phase space pre-correction, allowing to reach shorter bunches, a much more uniform current distribution and in general to control better the whole compression process. Here we report the results of numerical studies on the SPARC bunch compression optimization through the use of a harmonic cavity, and the design of a C-band RF system to implement it. The proposed system consists in a multi-cell SW cavity powered by a moderate portion of the total RF power spilled from the C-band power plant already installed for the linac energy upgrade.

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TUPWA062

GaAs Photocathode Activation with CsTe Thin Film

photon, electron, cathode, vacuum

1567

M. Kuriki, Y. Seimiya, K. Uchida
HU/AdSM, Higashi-Hiroshima, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Funding: This work is partly supported by MEXT/JSPS KAKENHI (Grant-in-Aid for scientific research) 24654054.
GaAs is an unique and advanced photocathode which can generate highly polarized and extremely low emittance electron beam. The photo-emission is possible up to 900nm wavelength. These advantages are due to NEA (Negative Electron Affinity) surface where the conduction band minimum is higher than the vacuum energy state. The NEA surface is artificially made with Cs-O/F evaporation on the cleaned GaAs surface, but the NEA surface is fragile, so that the emission is easily lost by poor vacuum environment and high emission density. NEA activation with any vital material is desirable. We found that the GaAs can be activated by CsTe thin film which is known as a vital photo-cathode material. The photo-electron emission spectrum extends up to 900 nm wavelength which corresponds to the band-gap energy of GaAs. The result strongly suggests that the surface becomes effectively NEA state by the CsTe thin film.

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TUPJE004

Narrow Band Coherent Edge Radiation at UVSOR-III

radiation, electron, laser, storage-ring

1613

M. Hosaka, O. Oodake, Y. Takashima, N. Yamamoto
Nagoya University, Nagoya, Japan
S. Bielawski, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
M. Katoh, T. Konomi, J. Yamazaki
UVSOR, Okazaki, Japan
H. Zen
Kyoto University, Kyoto, Japan

Edge radiation can be an interesting new light source because of its property that the radiation is well collimated and is radially polarized. We are developing coherent light sources in the THz region at UVSOR-III storage ring. We have already succeeded in producing a narrow band coherent THz radiation by manipulating the interaction of a relativistic electron bunch with an amplitude modulated laser with. Recently a simplified tentative beamline for detection of the edge radiation is installed at downstream of a short straight section of UVSOR-III. Coherent radiation from electron bunches after the interaction with the amplitude modulated laser is observed. Detailed measurements of polarizations and special distribution of the radiation are underway. The latest status of the study will be reported.

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TUPJE012

Preliminary Result of Photon Counting Acquisition Scheme for Laser Pump/X-ray Probe Experiments

laser, synchrotron, detector, timing

1638

J. He, J.S. Cao, G. Gao, Y.F. Sui, Y. Tao, J.H. Yue, Z. Zhang, Y.F. Zhou
IHEP, Beijing, People's Republic of China

Funding: This work is supported by the NSFC under grant No.11305186
R&D project has been initiated for a proposed ultralow emittance (~50pm.rad) synchrotron light source built in Beijing. The R&D includes the development of high repetition rate laser pump/X-ray probe for ultrafast dynamics detection in future source. In a typical laser pump/X-ray probe measurement, the X-ray pulse follows a laser pulse in adjustable delay. We are interested in the difference between laser on and laser off at different delay, which will snapshot dynamic process. To capture this trivial difference, it requires the acquisition system to single out the signal from this special X-ray pulse at adequate S/N ratio. For the R&D of high repetition rate pump-probe, we have set up a prototype counting acquisition system based on NIM modular electronics, which was tested in Beijing Synchrotron Radiation Facility (BSRF). The laser will be synchronized with a camshaft bunch at 124 kHz, a tenth of the revolution frequency. Avalanche Photo Diode (APD) was used to detect the X-ray pulse from this camshaft bunch due to its nanosecond response. Before the laser is delivered, we mimic the 124 kHz laser- on signal. The signals from APD are separated by power dividers into two Constant Fraction Discriminator (CFD) input channels. The signal in laser-on/off channel is gated out at 1.24MHz using the 1.24MHz timing signal divided from 499.8 MHz RF signal, while the mimic laser-on signal gated out at 124 kHz. Multiplied by ten times, the mimic laser-on signal counts should be consistent with the laser-on+off counts, if our counting modular works well. We carried out this test at 1W1B wiggler beam line to measure the Fe fluorescence signal. The performance of our system is demonstrated in the good consistency between mimic laser on and laser on+off signals.

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TUPJE058

Preparation of Polycrystalline and Thin Film Metal Photocathodes for Normal Conducting RF Guns

cathode, gun, electron, cavity

1759

S. Mistry, M.D. Cropper
Loughborough University, Leicestershre, United Kingdom
A.N. Hannah, K.J. Middleman, B.L. Militsyn, T.C.Q. Noakes, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

A comparison of quantum efficiency (QE) and work function (wf) measurements of polycrystalline and thin film metal photocathodes for use in NCRF guns, similar to the S-band gun under development for CLARA project at Daresbury, are reported. Cu and Nb thin films were grown onto a Si substrate by magnetron sputtering and subsequently were prepared by annealing and Ar ion sputtering. To determine the surface chemistry, x-ray photoelectron spectroscopy was employed. QE measurements were enabled using a UV laser source giving 266 nm light. Wf measurements were carried out using a kelvin probe and ultraviolet photoelectron spectroscopy. Annealing the Cu thin film to 250°C yielded a QE of 1.2E-4; one order of magnitude higher than the QE for sputter cleaned and post annealed polycrystalline Cu. The optimum QE measurement for Nb thin film was 2.6·10^-4, which was found to be comparable to the results obtained for cleaned bulk Nb. Analysis of XPS data of these metals suggest surface composition and surface chemistry are main contributing factors to the QE and WF.

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TUPMA042

THz Radiation Generation in a Multimode Wakefield Structure

radiation, wakefield, electron, linac

1929

S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin
BNL, Upton, Long Island, New York, USA
W. Gai, D. Wang, A. Zholents
ANL, Argonne, Illinois, USA

Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0009571
A number of methods for producing sub-picosecond beam microbunching have been developed in recent years. A train of these bunches is capable of generating THz radiation via multiple mechanisms like transition, Cherenkov and undulator radiation. We utilize a bunch train with tunable spacing to selectively excite high order TM0n - like modes in a multimode structure. In this paper we present experimental results obtained at the Accelerator Test Facility of Brookhaven National Laboratory.

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TUPMA043

Experimental Test of Semiconductor Dechirper

electron, wakefield, FEL, emittance

1932

S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Baturin
LETI, Saint-Petersburg, Russia
M.G. Fedurin, K. Kusche, C. Swinson
BNL, Upton, Long Island, New York, USA
W. Gai, S. Stoupin, A. Zholents
ANL, Argonne, Illinois, USA

Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0006299
We report the observation of de-chirping of a linearly chirped (in energy) electron bunch by its passage through a 4 inch long rectangular waveguide loaded with two silicon bars 0.25 inch thick and 0.5 inch wide. Silicon being a semiconductor has a conductivity that allows it to drain the charge fast in case if some electrons get intercepted by the dechirper. At the same time the conductivity is low enough for the skin depth to be large (on the order of 1 cm) making the silicon loaded waveguide a slow wave structure supporting wakefields that dechirp the beam.

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TUPTY027

SixTrack Simulations of Beam Cleaning During High-beta Operation in the LHC

simulation, background, proton, collimation

2060

R. Bruce
CERN, Geneva, Switzerland

The 1000 m high-beta run in the LHC provided very clean conditions for observing experimental backgrounds. In ATLAS, a much higher background was observed for Beam 2 than for Beam 1, suspected to be caused by upstream showers from beam losses on collimators or aperture. However, no local beam losses were observed in the vicinity. This paper presents SixTrack simulations of the beam cleaning during the high-beta run. The results demonstrate that, for the special optics and collimator settings used, the highest loss location in IR1 is at the TAS absorber just in front of the ATLAS detector, where no beam loss monitor is installed. Furthermore, the highest losses are seen in Beam 2. The results could thus provide a possible explanation of the ATLAS observations, although detailed shower calculations would be needed for a quantitative comparison.

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TUPTY056

Beam-Based Measurements of Long Range Transverse Wakefields in CLIC Main Linac Accelerating Structure

wakefield, positron, electron, linac

2153

H. Zha, A. Grudiev, A. Latina, D. Schulte, A. Solodko, W. Wuensch
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway
G. De Michele
EPFL, Lausanne, Switzerland
G. De Michele
PSI, Villigen PSI, Switzerland
N. Lipkowitz, G. Yocky
SLAC, Menlo Park, California, USA

The baseline design of CLIC (Compact Linear Collider) uses X-band accelerating structures in the main linac. Every accelerating structure cell has four waveguides, terminated with individual RF loads, to damp the unwanted long-range transverse wakefields, in order to maintain beam stability in multi-bunch operation. In order to experimentally verify the calculated suppression of the wakefields, a prototype structure has been built and installed in FACET test facility at SLAC. The results of the measurements of the wakefields in the prototype structure by means of positron and electron bunches are presented.

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TUPWI003

Proton Beam Applications for Silicon Bulk Micromachining

proton, ion, 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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TUPWI005

Proton Irradiations of Micro-TOM Red Hairy Roots to Mimic Space Conditions

proton, controls, radiation, framework

2249

M. Vadrucci, A. Ampollini, G. Bazzano, P. Nenzi, L. Picardi, C. Ronsivalle, V. Surrenti
ENEA C.R. Frascati, Frascati (Roma), Italy
F. Ambrosini
Università di Roma "La Sapienza", SAPIENZA-DIET, Roma, Italy
E. Benvenuto, A. Desiderio, S. Massa, C. Snels, M.E. Villani
ENEA Casaccia, Roma, Italy

Funding: Radiation Sources Laboratory UTAPRAD Department ENEA C.R. Frascati Via E. Fermi, 45 00044 Frascati (RM), Italy ENEA
The purpose of the BIOxTREME project, launched by ENEA and funded by ASI (Italian Space Agency), is to formulate new biological drugs having a stimulant activity on the immune system finalizing the production for a ready to use resource in Bioregenerative Life Support Systems (BLSSs) for space missions with extended durations, in deep space, and with multiple crews. One of the project tasks is to study the effects of physical insults on plants, simulating cosmic environment on production platforms by static magnetic fields, microgravity and ionizing radiation. In order to examine the biological effects, to test plant radio-resistance and to build dose-response curves we carried out proton irradiations of a tomato cultivar Micro-Tom red hairy roots with the TOP-IMPLART accelerator at the ENEA Frascati Research center. The biological samples were placed in a holder specially made in a movable real-time monitoring chamber calibrated in dose. The fluence-homogeneity measurements over the sample and the calibration of the monitoring system were performed using GafChromic EBT3 films. The paper describes the experimental set-up and reports the preliminary results.

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TUPWI017

Single-shot Multi-MeV Ultrafast Electron Diffraction on VELA at Daresbury Laboratory

electron, gun, FEL, scattering

2278

L.K. Rudge, D. Angal-Kalinin, J.A. Clarke, F. Jackson, J.K. Jones, A. Kalinin, S.L. Mathisen, J.W. McKenzie, B.L. Militsyn, B.D. Muratori, T.C.Q. Noakes, Y.M. Saveliev, D.J. Scott, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
P. Aden, R.J. Cash, D.M.P. Holland, M.D. Roper
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
P.D. Lane, D.A. Wann
University of York, York, United Kingdom
M. Surman
STFC/DL/SRD, Warrington, Cheshire, United Kingdom
J.G. Underwood
UCL, London, United Kingdom

Funding: This work was funded by STFC
Accelerator based Ultrafast Electron Diffraction (UED) is a technique for obtaining static structures and for studying sub-100 fs dynamic structural changes on the atomic scale. In this paper we present the first electron diffraction results obtained from the VELA accelerator in 2014. The accelerator was operated to provide typically 4MeV/c electron bunches. Diffraction patterns were observed with <<1 pC transported to the detection screen. Single shot and multi-shot accumulated diffraction data are presented from single crystal and polycrystalline samples, including Au, Al, Pt and C. Contamination of the diffraction pattern with dark current contributions is an issue. A variable size aperture directly in front of the sample offers some mitigation, but at the expense of reduced charge contributing to the diffraction pattern. We discuss future developments for electron diffraction on VELA including further beam optimization, measurement of bunch length with a newly installed Transverse Deflecting Cavity, and the planned developments for pump-probe studies.

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TUPWI028

Varying Amplitude Raster Pattern for High Power Isotope Production Targets

target, isotope-production, flattop, proton

2298

J.S. Kolski, J. Audia, H.T. Bach, Y.K. Batygin, J.T. Bradley III, M. Connors, J.W. Engle, E. Espinoza, E. Figueroa, M.J. Hall, M.P. Martinez, F.M. Nortier, D. Reass, W. Roybal, H.A. Watkins
LANL, Los Alamos, New Mexico, USA

The Isotope Production Facility (IPF) at LANSCE produces medical radionuclides strontium-82 and germanium-68 by bombarding rubidium chloride and gallium metal targets respectively with a 100 MeV proton beam, 230 uA average current. Rastering the proton beam is necessary to distribute beam power deposited as heat in the target and allow for higher average beam current for isotope production. We currently use a single circle raster pattern with constant amplitude and frequency. In this paper, we demonstrate two different varying amplitude raster patterns (concentric circle and spiral) to achieve uniform target coverage and expose more target volume to beam heating. In this proof-of-principle experiment, we compare beam spot uniformity measured by irradiating films and foils for both raster patterns.

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TUPWI042

Initial Results from Streaked Low-energy Ultra-fast Electron Diffraction System

electron, gun, simulation, diagnostics

2339

J.J. Hartzell, R.B. Agustsson, S. Boucher, L. Faillace, A.V. Smirnov
RadiaBeam, Santa Monica, California, USA
P. Musumeci, E.W. Threlkeld
UCLA, Los Angeles, USA

RadiaBeam, in collaboration with UCLA, is developing an inexpensive, low-energy, ultra-fast, streaked electron diffraction (S-UED) system which allows one to reconstruct a single ultrafast event with a single pulse of electrons using and RF deflector. The high-frequency (GHz), high voltage, phase-locked RF field in the deflector enables temporal resolution of atomic events as fine as sub-100 fs. In this paper, we present an overview of the system being developed and the initial experimental results. We also discuss the challenges based on our design of a UED system that incorporates a novel, high-resolution dielectric-loaded RF deflector and a solid-state X-band amplifier.

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TUPWI048

Experimental Demonstration of an Interaction Region Beam Waist Position Knob for Luminosity Leveling

luminosity, optics, controls, detector

2357

Y. Hao, Y. Luo, A. Marusic, G. Robert-Demolaize, X. Shen
BNL, Upton, Long Island, New York, USA
M. Bai
FZJ, Jülich, Germany
Z. Duan
IHEP, Beijing, People's Republic of China

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this paper, we report on the experimental implementation of the model-dependent control of the interaction region beam waist position (s* knob) at the Relativistic Heavy Ion Collider (RHIC). The s* adjustment provides an alternative way of controlling the luminosity and is the only known method to control the luminosity and to reduce the pinch effect of the future eRHIC. We first demonstrate the effectiveness of the s* knob in luminosity controlling and its application in the future electron ion collider, eRHIC, followed by details of the experimental demonstration of such knob in RHIC.

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WEXB1

Coherent Synchrotron Radiation in Energy Recovery Linacs

FEL, electron, linac, dipole

2387

C.C. Hall, S. Biedron, A.L. Edelen, S.V. Milton
CSU, Fort Collins, Colorado, USA
S.V. Benson, D. Douglas, R. Li, C. Tennant
JLab, Newport News, Virginia, USA
B.E. Carlsten
LANL, Los Alamos, New Mexico, USA

Collective beam effects, including coherent synchrotron radiation (CSR), have been studied on free-electron lasers (FELs). Here we will discuss a particular case of the CSR effects, that in energy-recovery linacs (ERLs). Special consideration is given to these machines because of their high average beam power and the architecture of the machine for energy recovery forces extreme bends. A recent study conducted on the JLab IR FEL looked at how CSR impacts both average energy and the energy spectrum of the beam. Such studies are important, both broadly, to the understanding of CSR and more specifically for a number of proposed ERL projects. A few proposed examples include the MEIC bunched beam cooler ERL design and ERL FELs for potential lithography purposes that would operate in the EUV range.

Slides WEXB1 [16.383 MB]

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WEXB3

Realization of Pseudo Single Bunch Operation with Adjustable Frequency

kicker, operation, timing, resonance

2396

C. Sun, G.J. Portmann, D. Robin, C. Steier
LBNL, Berkeley, California, USA

Funding: This work is supported by the Director Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
We present the concept and results of pseudo-single-bunch (PSB) operation–a new operational mode at the advanced light source–that can greatly expand the capabilities of synchrotron light sources to carry out dynamics and time-of-flight experiments. In PSB operation, a single electron bunch is displaced transversely from the other electron bunches using a short-pulse, high-repetition-rate kicker magnet. Experiments that require light emitted only from a single bunch can stop the light emitted from the other bunches using a collimator. Other beam lines will only see a small reduction in flux due to the displaced bunch. As a result, PSB allows to run timing experiments during the multibunch operation. Furthermore, the time spacing of PSB pulses can be adjusted from milliseconds to microseconds with a novel “kick-and-cancel” scheme, which can significantly alleviate complications of using high-power choppers and substantially reduce the rate of sample damage.

Slides WEXB3 [128.794 MB]

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WEYB1

Benchmarking and Application of Space Charge Codes for Rings

space-charge, simulation, resonance, lattice

2402

S. Machida
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

This presentation should present an overview of efforts for benchmarking and application of space charge codes for rings. After briefly recalling the historical background of the simulation efforts of space charge effects in rings, we will overview the present benchmarking efforts against experimental results.

Slides WEYB1 [6.541 MB]

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WEAB2

Beam and Spin Dynamics for Storage Ring Based EDM Search

dipole, simulation, storage-ring, resonance

2454

A. Lehrach
FZJ, Jülich, Germany

Funding: On behalf of the JEDI collaboration and JARA-FAME (Jülich Aachen Research Alliance)
Permanent EDMs (electric dipole moment) of fundamental particles violate both time invariance T and parity P. Assuming the CPT theorem this implies CP violation. The Standard Model (SM) predicts non-vanishing EDMs, their magnitudes, however, are expected to be unobservably small with current techniques. Hence, the discovery of a non-zero EDM would be a signal for “new physics”. As a first step towards EDM searches of charged particles in storage rings, R&D work at the Cooler Synchrotron COSY is pursued. On a longer time scale, the design and construction of a dedicated storage ring will be carried out. Spin-tracking simulations are absolutely crucial to explore the feasibility of the planned storage ring EDM experiments and to investigate systematic limitations. For a detailed study during the storage and buildup of the EDM signal, one needs to track a large sample of particles for billions of turns. Benchmarking experiments are performed at the Cooler Synchrotron COSY to check and to further improve the simulation tools and prototype accelerator components are tested. Finally, the layout of a dedicated storage ring has to be optimized by a full simulation of spin motion.

Slides WEAB2 [1.459 MB]

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WEAD1

Commissioning and Recent Experimental Results at the Argonne Wakefield Accelerator Facility (AWA)

wakefield, electron, acceleration, laser

2472

M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, J.H. Shao, D. Wang, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
J.H. Shao, D. Wang
TUB, Beijing, People's Republic of China

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357.
The commissioning of the upgraded AWA facility has been recently completed. The L-band electron gun has been fully commissioned and has been successfully operated with its Cesium Telluride photocathode at a gradient of 80 MV/m. Single bunches of up to 100 nC, and bunch trains of up to 32 bunches have been generated. The six new pi-mode accelerating cavities bring the beam energy to 75 MeV. Initial measurements of the beam parameters have been performed. This intense beam has been used to drive high gradient wakefields in several structures. A second beamline provides electron bunches to probe the wakefields generated by the intense drive beam. One of the main goals of the facility is to generate short RF pulses with GW power levels, corresponding to accelerating gradients of hundreds of MV/m and energy gains on the order of 100 MeV per structure.

Slides WEAD1 [2.091 MB]

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WEPWA005

Simulations Study for Self-Modulation Experiment at PITZ

plasma, electron, wakefield, simulation

2496

G. Pathak, F.J. Grüner
Uni HH, Hamburg, Germany
C. Benedetti, C.B. Schroeder
LBNL, Berkeley, California, USA
M. Groß, F. Stephan
DESY Zeuthen, Zeuthen, Germany
A. Martinez de la Ossa, T.J. Mehrling, J. Osterhoff
DESY, Hamburg, Germany

Self-modulation (SM) of proton beams in plasma has recently gained interest in context with the ongoing PWFA experiment of the AWAKE collaboration at CERN. Instrumental for that experiment is the SM of a proton beam to generate bunchlets for resonant wave excitation and efficient acceleration. A fundamental understanding of the underlying physics is vital, and hence an independent experiment has been set up at the beamline of the Photo Injector Test Facility at DESY, Zeuthen Site (PITZ), to study the SM of electron beams in a plasma. This contribution presents simulation results on SM experiments at PITZ using the particle-in-cell code HiPACE. The simulation study is crucial to optimize the beam and plasma parameters for the experiment. Of particular interest is the energy modulation imprinted onto the beam by means of the generated wakefields in the plasma. With the support of simulations the observation of this information in the experiment can be used to deduce key properties of the accelerating electric fields such as their magnitude and their phase velocity, both of significant importance for the design of self-modulated plasma-based acceleration experiments.

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WEPWA006

Laser Propagation Effects During Photoionization of Meter Scale Rubidium Vapor Source

laser, plasma, proton, wakefield

2499

J.T. Moody, F. Batsch, A. Joulaei, P. Muggli, E. Öz
MPI-P, München, Germany
N. Berti, J. Kasparian
University of Geneva, GAP Biophotonics, Carouge, Switzerland

The baseline AWAKE experiment requires a 10 meter long plasma source with a density of 10¹⁵ cm􀀀^-3 and a density uniformity of 0.2%. To produce this plasma, a temperature stabilized rubidium vapor source is photoionized by a terawatt peak power laser pulse. In this paper we describe the laser pulse evolution within the plasma source including the dispersive, diffractive, and photoionization effects on the laser pulse. These calculations will be experimentally investigated in a meter long heat pipe oven using scaled laser parameters.

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WEPWA007

The AWAKE Proton-driven Plasma Wakefield Experiment at CERN

plasma, electron, wakefield, injection

2502

P. Muggli
MPI-P, München, Germany

Funding: For the AWAKE collaboration
The AWAKE experiment at CERN * aims at studying plasma wakefield generation and acceleration driven by proton bunches. The first experiments will focus on the self-modulation instability of the long (~12cm, rms) proton bunch in the plasma. This instability is used to transform the incoming bunch into a train of short bunches with a period approximately equal to the plasma wavelength, ~1.2mm at a nominal plasma electron density of 7·10¹⁴/cc. These experiments are planned for the end of 2016. Later, low energy (~15MeV) electrons will be externally injected to sample the wakefields and be accelerated beyond 1GeV. The main goals of the experiment will be summarized and the progress with the plasma source, beam diagnostics and injection method will be presented.
* AWAKE Collaboration, Plasma Phys. Control. Fusion 56 084013 (2014)

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WEPWA014

Low Temperature Properties of 20 K Cooled Test Cavity for C-band 2.6-cell Photocathode RF Gun

cavity, cryogenics, gun, resonance

2519

T. Tanaka, M. Inagaki, K. Nakao, K. Nogami, T. Sakai
LEBRA, Funabashi, Japan
M.K. Fukuda, T. Takatomi, J. Urakawa, M. Yoshida
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan
T.S. Shintomi
Nihon University, Tokyo, Japan

Funding: Work supported by the Photon and Quantum Basic Research Coordinated Development Program of the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT).
A cryogenic C-band 2.6-cell photocathode RF gun, which operates at 20 K, is under development at Nihon University for future possibility of use in a compact linac-driven X-ray source. The cavity material is 6N8 high purity copper, the RRR of which being expected to be higher than 3000. A 2.6-cell pi-mode test cavity was fabricated for investigation of the properties under low temperature of 20 K*. Ultraprecision machining and diffusion bonding of the cavity were carried out in KEK. The operating frequency of the RF gun cavity is 5712 MHz. The machining dimensions of the test cavity were determined by taking into account the contraction of copper from room temperature to 20 K by approximately 0.33 %. The resonant frequency observed at around 21 K was 5711.761 MHz, which is 185 kHz higher than the expected value that was deduced from the resonant frequency obtained at 23.5 degree C in vacuum and the linear expansion coefficient data for OFC copper by NIST**. The unloaded Q-value of 64500 obtained at 21 K is in agreement with the SUPERFISH calculation when the surface resistance of the RRR=3000 copper was specified with taking the anomalous skin effect into account.
* T. Tanaka et al., Proceedings of IPAC2014, 658-660, http://accelconf.web.cern.ch/AccelConf
/IPAC2014/papers/mopri030.pdf
** http://cryogenics.nist.gov/MPropsMAY/OFHC%20Copper/OFHC_Copper_rev.htm

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WEPWA018

Re-acceleration of Ultra Cold Muon in J-PARC MLF

acceleration, linac, rfq, proton

2532

M. Yoshida, F. Naito
KEK, Ibaraki, Japan
S. Artikova, Y. Kondo
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
K. Torikai
Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan

Funding: MEXT KAKENHI Grant Number 6108718
The ultra cold muon beam by two-photon laser resonant ionization of muonium atoms is unique way to obtain very low emittance muon beam. Its muon source is a surface muon from the muon target in MLF where one percent proton beam from J-PARC RCS is reacted. In close collaboration with the Muon Science Es- tablishment (MUSE) at Material and Life science experi- mental Facility (MLF) of the Japan Proton Accelerator Re- search Complex (J-PARC), we are developing the reacceleration system of the ultra cold muon beam. Its optimum accelerating structure is similar to a proton accelerator in low beta part and an electron accelerator in high beta part. Further the muon bunch is only two bunch corresponding to the bunch structure of the J-PARC RCS. Thus we are testing the dielectric transmission line accelerator based on the photoconductive switch as the altenative acceleration method.

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WEPWA023

Development of Muon LINAC for the Muon g-2/EDM Experiment at J-PARC

acceleration, target, rfq, cavity

2541

M. Otani, Y. Fukao, T. Mibe, N. Saito, M. Yoshida
KEK, Tsukuba, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan
Y. Kondo
JAEA, Ibaraki-ken, Japan

The muon anomalous magnetic moment (g-2) and electric dipole moment (EDM) are one of the effective paths to beyond Standard Model of elementary particle physics. The E34 experiment aims to measure g-2 with a precision of 0.1 ppm and search EDM with a sensitivity to 10-21 e*cm with high intensity proton driver at J-PARC and a newly developed novel technique of the ultra-cold muon beam. The ultra-cold muons, which are generated from surface muons by the thermal muonium production and laser ionization, are accelerated to 300 MeV/c by muon linear accelerator. The muon LINAC consists of RFQ and following three types of the RF cavities. The muon acceleration to this energy will be the first case in the world. This poster reports about status of the initial acceleration test with RFQ and the development of the RF cavities, especially for the middle beta section.

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WEPWA025

RF Acceleration of Ions Produced by Short Pulse Laser

ion, laser, rfq, 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, ion-source, electron, operation

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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WEPWA032

CsK2Sb Growth Studies: Towards High Quantum Efficiency and Smooth Surfaces

cathode, simulation, emittance, detector

2566

S.G. Schubert, M. Gaowei, J. Sinsheimer, J. Smedley
BNL, Upton, Long Island, New York, USA
Z. Ding, E.M. Muller
SBU, Stony Brook, New York, USA
J. Kühn
HZB, Berlin, Germany
H.A. Padmore, J.J. Wong
LBNL, Berkeley, California, USA
J. Xie
ANL, Argonne, Illinois, USA

Funding: This work was supported by the US DOE, under Contracts DE-AC02-05CH11231, DE-AC02-98CH10886, KC0407-ALSJNT-I0013, DE-FG02-12ER41837 and the German BMBF, Helmholtz-Association and Land Berlin.
The properties of CsK2Sb, make this material an ideal candidate as photocathode for electron injector use. Producing photocathodes with quantum efficiencies with 7% and greater at 532 nm poses no challenge, nevertheless the traditional growth mechanisms, which are based on a sequential deposition of Antimony, Potassium and Cesium at a temperature gradient yield a rough surface with a rms roughness in the range of 25 nm. Surface roughness’s in this region impacts the emittance. At an accelerating field of 3 MV/m an rms surface roughness of 25 nm is the dominant effect on emittance and will limit injector performance. Studies are performed to optimize roughness. Various growth procedures are exploited and the surface roughness compared.

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WEPWA035

Initial EEX-based Bunch Shaping Experiment Results at the Argonne Wakefield Accelerator Facility

dipole, simulation, cavity, emittance

2575

G. Ha, M.-H. Cho, W. Namkung
POSTECH, Pohang, Kyungbuk, Republic of Korea
M.E. Conde, D.S. Doran, W. Gai, G. Ha, C.-J. Jing, K.-J. Kim, W. Liu, J.G. Power, Y.-E. Sun, C. Whiteford, E.E. Wisniewski, A. Zholents
ANL, Argonne, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Funding: This work is partly supported by POSTECH BK²¹⁺ and Argonne National Laboratory
A program is under development at Argonne National Laboratory to use an emittance exchange (EEX) beamline to perform longitudinal bunch shaping (LBS). The double dog-leg EEX beamline was recently installed at the Argonne Wakefield Accelerator (AWA) and the goals of the proof-of-principle experiment are to demonstrate LBS and characterize its deformations from the ideal shape due to higher-order and collective effects. The LBS beamline at the AWA consists of insert-able transverse masks mounted on an actuator and four quadrupoles (to manipulate the transverse phase space) before the EEX beamline, which consists of two identical dog-legs and a deflecting cavity. The mask and input beam parameters are varied during the experiment to explore the shaping capability and clarify the deformation sources and their mitigation. Progress on the commissioning of the LBS beamline, initial experimental data and benchmarks to GPT simulations will be presented.

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WEPWA044

The Alignment of the MICE Tracker Detectors

alignment, emittance, detector, scattering

2597

M.A. Uchida
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The Muon Ionization Cooling experiment (MICE) has been designed to demonstrate the reduction of the phase-space volume (cooling) occupied by a muon beam using the ionization-cooling technique. This demonstration will be an important step in establishing the feasibility of muon accelerators for particle physics. The emittance of the beam will be measured before and after the cooling cell using a solenoidal spectrometer. Each spectrometer will be instrumented with a high-precision scintillating-fibre tracking detector (Tracker). The Trackers will be immersed in a uniform magnetic field of 4T and will measure the normalised emittance reduction with a precision of 0.1%. A thorough knowledge of the alignment of the Trackers is essential for this accuracy to be achieved. The Trackers are aligned: mechanically inside the spectrometer solenoids, with respect to the MICE experimental hall, to one another, and to the magnetic and beam axes. These methods are described here.

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WEPWA049

Low Energy Beam Tracking Under Scattering for a Cold Electron Source in Manchester

electron, scattering, emittance, extraction

2615

R.B. Appleby, W. Bertsche, O. Mete, G.X. Xia
UMAN, Manchester, United Kingdom
M.A. Harvey, M. Jones, A.J. Murray
The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
B. Kyle
University of Manchester, Manchester, United Kingdom

High quality electron beams, with high spatial and temporal resolution, have an important use in electron diffraction experiments to probe and study the constituents of matter. A cold electron source is being developed based on electron ionisation from an atom cloud trapped by using AC magneto-optical methods in the University of Manchester. The technique will produce bunches of electrons well suited for high precision and single shot electron diffraction. In this paper issues of modelling at low energies for this state of art electron source with very low energy spread are presented, with a focus on newly developed tools to model the scattering in the meshes used to support the extraction electric fields. The dependence on emittance growth on mesh wire thickness is studied.

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WEPWA067

Acoustic Breakdown Localization in RF Cavities

cavity, simulation, timing, diagnostics

2658

P.G. Lane, P. Snopok, Y. Torun
Illinois Institute of Technology, Chicago, Illinois, USA
E. Behnke, I.Y. Levine
Indiana University South Bend, South Bend, USA
D.W. Peterson
Fermilab, Batavia, Illinois, USA

Funding: US Department of Energy
Current designs for muon cooling channels require high-gradient RF cavities to be placed in solenoidal magnetic fields in order to contain muons with large transverse emittances. It has been found that doing so reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields it would be helpful to have a diagnostic tool which can detect breakdown and localize the source of the breakdown inside the cavity. We report here on acoustic simulations and comparisons with experimental acoustic data of breakdown from several RF cavities. Included in this analysis are our most recent results from attempting to localize breakdown using these data.

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WEPJE002

Photoinjector Improvement and Control by Surface Acoustic Waves

electron, photon, controls, linac

2678

R.P. Johnson
Muons, Inc, Illinois, USA
A. Afanasev, C.E. Korman
GWU, Washington, USA

A new technique is being developed to enhance the efficiency of photocathodes used for electron sources to improve emission capabilities of electron sources, such as bunch charge and average current. The proposed technique is based on the use of surface acoustical waves (SAW) generated on the piezoelectric surface of a GaAs photocathode. The generation of SAW on piezoelectric substrates is known to produce strong piezoelectric fields that propagate on the surface of the material. These fields can significantly suppress recombination effects and result in enhanced quantum efficiency of photoemission. Experimental measurements of photoemission quantum efficiency will be done on semiconductors used as photocathode materials (e.g., GaAs) in presence of SAW with varied parameters. The experimental results will be used as input for physics modeling that will provide a basis for design of operational SAW-enhanced photocathodes. While the improved quantum efficiency and parameter control expected from the use of SAW will be useful for many research devices and accelerators, the commercialization of such a widespread field as electron microscopy is compelling.

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WEPJE006

Dielectric Wakefield Accelerator Experiments at ATF

wakefield, electron, dipole, controls

2681

D.Y. Shchegolkov, E.I. Simakov
LANL, Los Alamos, New Mexico, USA
S.P. Antipov
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin
BNL, Upton, Long Island, New York, USA

Funding: This work is supported by the U.S. Department of Energy through the Laboratory Directed Research and Development (LDRD) program at Los Alamos National Laboratory.
Dielectric wakefield acceleration (DWA) presents us with means to achieve the accelerating gradient high above the limits of conventional accelerators. In a typical DWA scheme a higher energy lower charge main bunch is accelerated in the wakefield produced by a preceding lower energy higher charge drive bunch inside of a hollow metal-encapsulated dielectric tube. To make use of as much energy of the drive bunch as possible, it is highly important that all parts of it decelerate uniformly. Close to uniform drive bunch deceleration can be achieved if its current is properly shaped.* At Accelerator Test Facility (ATF) at BNL we shaped the current of a chirped electron beam with an adjustable mask placed inside of the highly dispersive region in the magnetic dogleg. We passed the shaped beam current through a quartz tube and observed the beam particles’ energy modulation at the tube’s output with a spectrometer. By tuning the mask we were able to control the beam energy modulation and thus the wakefield profile in the tube.
* B. Jiang, C. Jing, P. Schoessow, J. Power, and W. Gai, PRSTAB 15, 011301 (2012).

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WEPJE016

INTENSE MUON BEAMS FROM THE CSNS SPALLATION TARGET

target, solenoid, proton, neutron

2708

Y. Bao, G.G. Hanson
UCR, Riverside, California, USA

Intense muon beams are useful for a wide range of physics experiments. Currently most of the muon beams are produced by protons hitting thin targets sitting upstream of spallation neutron targets. The intensity of the muons is greatly limited by the small thickness of the muon targets, which are intended to have minimum impact on the proton beams. When the majority of the proton beam hits the spallation target, a large number of pions/muons are produced. After being captured in a solenoidal magnetic field, a high intensity muon beam can be produced. In this paper we take the Chinese Spallation Neutron Source (CSNS) target as an example and investigate the production of high intensity muon beams. Two possibilities are presented in this paper: an upstream collection of surface muons and a downstream collection of pions which is followed by a decay and compress channel to obtain a high intensity muon beam. Simulations show both methods can reach high intensities which could significantly increase the statistics of many experiments.

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WEPJE020

The Two Beam Acceleration Staging Experiment at Argonne Wakefield Accelerator Facility

acceleration, wakefield, timing, kicker

2714

C.-J. Jing, S.P. Antipov, A. Kanareykin, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, J.H. Shao, D. Wang, E.E. Wisniewski
ANL, Argonne, Illinois, USA
J. Shi
TUB, Beijing, People's Republic of China

Funding: DoE SBIR Program
Staging, defined as the accelerated bunch in a wakefield accelerator continues to gain energy from sequential drive bunches, is one of the most critical technologies, yet be demonstrated, required to achieve high energy. Using the Two Beam Acceleration (TBA) beamline at Argonne Wakefield Accelerator facility, we will perform a staging experiment using two X-band TBA units. The experiment is planned to conduct in steps. We report on the most recent progress.

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WEPJE025

Phase Space Density as a Measure of Cooling Performance for the International Muon Ionization Cooling Experiment

emittance, simulation, luminosity, scattering

2726

J.S. Berg
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 International Muon Ionization Cooling Experiment (MICE)* is an experiment to demonstrate ionization cooling of a muon beam in a beamline that shares characteristics with one that might be used for a muon collider or neutrino factory. I describe a way to quantify cooling performance by examining the phase space density of muons, and determining how much that density increases. This contrasts with the more common methods that rely on the covariance matrix and compute emittances from that. I discuss why a direct measure of phase space density might be preferable to a covariance matrix method. I apply this technique to an early proposal for the MICE final step beamline. I discuss how matching impacts the measured performance.
* http://mice.iit.edu/ I am not a MICE collaboration member, and nothing herein should be construed as representing the work or views of the collaboration.

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WEPJE027

Partial Return Yoke for MICE Step IV and Final Step

solenoid, shielding, simulation, instrumentation

2732

H. Witte, J.S. Berg, S.R. Plate
BNL, Upton, Long Island, New York, USA
A.D. Bross
Fermilab, Batavia, Illinois, USA
J.S. Tarrant
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
This paper reports on the progress of the design and construction of a retro-fitted return yoke for the international Muon Ionization Cooling Experiment (MICE). MICE is a proof-of-principle experiment aiming to demonstrate ionization cooling experimentally. In earlier studies we outlined how a partial return yoke can be used to mitigate stray magnetic field in the experimental hall; we report on the progress of the construction of the partial return yoke for MICE Step IV. We also discuss an extension of the Partial Return Yoke for the final step of MICE; we show simulation results of the expected performance.

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WEPMA030

Design and Characterization of Permanent Magnetic Solenoids for REGAE

solenoid, emittance, electron, simulation

2822

M. Hachmann, K. Flöttmann, T. Gehrke, F. Mayet
DESY, Hamburg, Germany

REGAE is a small electron linear accelerator at DESY. In order to focus short and low charged electron bunches down to a few micrometre permanent magnetic solenoids were designed, assembled and field measurements were done. Due to a shortage of space close to the operation area an in-vacuum solution has been chosen. Furthermore a tworing design made of wedges has been preferred in terms of beam dynamic issues. To keep the field quality of a piecewise built magnet still high a sorting algorithm for the wedge arrangement has been developed and used for the construction of the magnets. The magnetic field of these solenoids has been measured with high precision and has been compared to the simulated magnetic field.

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WEPMA040

Magnet Studies for the Accelerator FLUTE at KIT

dipole, linac, multipole, simulation

2849

S. Hillenbrand, A. Bernhard, A.-S. Müller, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Sauter, S. Schott, M. Schuh, S. Schulz, M. Weber, P. Wesolowski, C. Widmann
KIT, Karlsruhe, Germany

At KIT we are currently constructing the compact linear accelerator FLUTE (Ferninfrarot Linac Und Test Experiment). This 41 MeV machine is aimed at accelerator physics and synchrotron radiation research, using ultra-short electron bunches. The electrons are generated at a photo-cathode using picosecond long UV laser pulses. A magnetic chicane is used to compress the bunches longitudinally to a few femtoseconds. This contribution describes both the magnet design, in particular the optimization of the chicane dipoles based on finite element method (FEM) simulations, as well as the implementation of a magnet measurement system.

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WEPMA054

A Disturbance-Observer-based Controller for LLRF Systems

controls, LLRF, beam-loading, cavity

2895

F. Qiu, D.A. Arakawa, Y. Honda, H. Katagiri, T. Matsumoto, S. Michizono, T. Miura, T. Obina
KEK, Ibaraki, Japan
S.B. Wibowo
Sokendai, Ibaraki, Japan

Digital low-level radio frequency (LLRFs) systems have been developed and evaluated in the compact energy recovery linac (cERL) at KEK. The required RF stabilities are 0.1% rms in amplitude and 0.1° rms in phase. These requirements are satisfied by applying digital LLRF systems. To further enhance the control system and make it robust to disturbances such as large power supply (PS) ripples and high-intensity beams, we have designed and developed a disturbance observer (DOB)-based control method. This method utilizes the RF system model, which can be acquired using modern system identification methods. Experiments show that the proposed DOB-based controller is more effective in the presence of high disturbances compared with the conventional proportional and integral (PI) controller. In this paper, we present the preliminary results based on the experiments with DOB-based controller.

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WEPMN008

Material Test of Proton Beam Window for CSNS

proton, target, neutron, operation

2927

H.J. Wang, L. Kang, H. Qu, L. Wu, D.H. Zhu
IHEP, Beijing, People's Republic of China

The proton beam window (PBW) is one of the key devices of China Spallation Neutron Source (CSNS). Material selection is of particular importance. A5083-O was selected in the previous work, and recently the material tests were done. The tests showed the material has good microstructure, physical and mechanical performance. Creep lifetime was analyzed based on the creep test. All the experiment showed the selected material is qualified.

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WEPMN015

Dark Current Imaging Experiment in an L-band RF Gun

cathode, solenoid, gun, electron

2952

J.H. Shao, H.B. Chen, J. Shi, D. Wang
TUB, Beijing, People's Republic of China
S.P. Antipov, S.V. Baryshev, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, D.S. Doran, W. Gai, W. Liu, J.G. Power, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA
F.Y. Wang, L. Xiao
SLAC, Menlo Park, California, USA

The localized high electric field enhancement or low work function is the trigger for strong field emission, which however has yet been well experimentally studied. Using an L-band photocathode gun test stand at Argonne Wakefield Accelerator Facility (AWA), we’ve constructed an imaging beam line to observe field emission current from predefined emitters on cathode. Preliminary experiment results are present. Future plan is discussed.

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WEPMN016

Observation of Dark Current Dependence on Stored Energy in an L-Band RF Gun

cathode, gun, solenoid, simulation

2956

J.H. Shao, H.B. Chen, J. Shi, D. Wang
TUB, Beijing, People's Republic of China
S.P. Antipov, S.V. Baryshev, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, D.S. Doran, W. Gai, W. Liu, J.G. Power, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA
F.Y. Wang, L. Xiao
SLAC, Menlo Park, California, USA

A pin cathode has been installed into an L-band photocathode gun to study the influence of stored energy on field emission. The stored energy was varied by tuning the recess of the cathode in order to have the same E-field on the cathode tip. We have observed 5 times difference of dark current level at the same E-field, while by varying the stored energy by three fold. Dynamics study reveals the difference is not caused by transmission, but by emission process itself. We'll present experiment results and discuss possible mechanisms about the phenomena.

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WEPMN017

High Power RF Radiation at W-band Based on Wakefields Excited by Intense Electron Beam

wakefield, electron, simulation, radiation

2960

D. Wang, C.-X. Tang
TUB, Beijing, People's Republic of China
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, E.E. Wisniewski
ANL, Argonne, Illinois, USA

We report the experiment design and preliminary results on high power RF generation at W-band based on coherent wakefields from the metallic periodic structure of 91 GHz PETS (power extraction and transfer structure), excited by intense electron beam at the Argonne Wakefield Accelerator (AWA) facility. The recently output RF power is 0.7 MW, with 67 MeV, 1.4 nC single electron beam going through the structure. The RF pulse length is 3.4 ns. We measure the energy loss of electron beam as reference to the RF generation, which agrees well with the simulation results. Next run is to increase the output RF power with higher charge and to excite coherent wakefields with electron bunch train. The output RF peak power is expected to be ~100 MW and the electrical field gradient can reach up to 400 MV/m, with RF pulse duration adjustable from few ns to 30 ns when excited with 5~10 nC charge in a single bunch and up to 32 sub bunches in total.

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WEPMN019

Calorimetric Power Measurements in X-band High Power RF

simulation, klystron, operation, linac

2967

X.W. Wu, H.B. Chen, L. Zhang
TUB, Beijing, People's Republic of China
N. Catalán Lasheras, B.J. Woolley, W. Wuensch
CERN, Geneva, Switzerland

With the aim to test prototype accelerating structures for CLIC at high-gradient, new klystron-based, X-band high power test stands are being built at CERN. These tests stands are referred to as Xboxes with Xbox1 and Xbox2 being already operational. Stainless steel loads are placed in the end of the Xbox-1 system to absorb the remaining power which comes out of the accelerating structure. Power information is important and needs to be measured precisely. A new power measuring method based on calorimetry is proposed independent from RF measurements subject to frequent calibration. The principles of the method and simulations are presented and the results of actual experimentation are used to validate the method. The results show calorimetric measurement is feasible method and have a good precision at this power level.

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WEPMN028

Preliminary Mechanical Design of Ceramic Pipe Film Coating Equipment at Hefei Light Source II

cathode, vacuum, injection, simulation

2988

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

Ceramic vacuum chambers are important components of the injection chamber at Hefei Light Source II (HLS II). The length of each Ceramic vacuum chamber is 350 mm and their inner surface is coated with TiN thin film whose properties are low secondary electron yield (SEY), good electrical conductivity, stability of performance, ability to block hydrogen permeation. Considering that the cross section of Ceramic pipe is racetrack structure, Ti plate was chose as the cathode to improve TiN thin film deposition rate. Meanwhile, the authors designed a motor drive magnetron sputtering film coating equipment to obtain uniform TiN film.

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WEPMN072

Status and Planned Experiments of the Hiradmat Pulsed Beam Material Test Facility at CERN SPS

proton, target, electronics, operation

3093

A. Fabich, N. Charitonidis, I. Efthymiopoulos, M. Meddahi
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA

Funding: EuCARD-2 is co-funded by the partners and the European Commission under Capacities 7th Framework Programme, Grant Agreement 312453.
HiRadMat (High Irradiation to Materials) is a facility at CERN designed to provide high-intensity pulsed beams to an irradiation area where material samples as well as accelerator component assemblies (e.g. vacuum windows, shock tests on high power targets, collimators) can be tested. The beam parameters (SPS 440 GeV protons with a pulse energy of up to 3.4 MJ, or alternatively lead/argon ions at the proton equivalent energy) can be tuned to match the needs of each experiment. It is a test area designed to perform single pulse experiments to evaluate the effect of high-intensity pulsed beams on materials in a dedicated environment, excluding long-time irradiation studies. The facility is designed for a maximum number of 10¹⁶ protons per year, in order to limit the activation of the irradiated samples to acceptable levels for human intervention. This paper will demonstrate the possibilities for research using this facility and go through examples of upcoming experiments scheduled in the beam period 2015/2016.

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WEPHA006

Recommissioning of the COLDEX Experiment at CERN

electron, cryogenics, vacuum, controls

3109

R. Salemme, V. Baglin, F. Bellorini, G. Bregliozzi, K. Brodzinski, P. Chiggiato, P. Costa Pinto, P. Gomes, A. Gutierrez, V. Inglese, B. Jenninger, R. Kersevan, E. Michel, M. Pezzetti, B. Rio, A. Sapountzis
CERN, Geneva, Switzerland

COLDEX (Cold bore Experiment), installed in the Super Proton Synchrotron (SPS) at CERN, is a test vacuum sector used in 2001-2004 to validate the Large Hadron Collider (LHC) cryogenic vacuum system with LHC type proton beams. Its cryostat houses a 2.2 m long copper perforated beam screen surrounded by a stainless steel cold bore, both individually temperature controlled down to 5 and 3 K, respectively. In the framework of the development for the High Luminosity upgrade of the LHC (HL-LHC), COLDEX has been re-commissioned in 2014. The objective of this re-commissioning is the validation of the performance of amorphous carbon coatings at cryogenic temperature with LHC type beams. The existing COLDEX beam screen has been dismounted and carbon coated, while a complete overhaul of the vacuum, cryogenic and control systems has been carried out. This contribution describes the phases of re-commissioning and reviews the current experimental set-up. An overview of the possible measurements with COLDEX, in view of its HL-LHC experimental program, is also presented.

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WEPHA007

Amorphous Carbon Coatings at Cryogenic Temperatures with LHC Type Beams: First Results with the COLDEX Experiment

electron, cryogenics, vacuum, simulation

3112

R. Salemme, V. Baglin, G. Bregliozzi, P. Chiggiato, R. Kersevan
CERN, Geneva, Switzerland

Extrapolations of electron cloud data from the Large Hadron Collider (LHC) Run 1 to the High Luminosity upgrade (HL-LHC) beam parameters predict an intolerable increase of heat load on the beam screens of the inner triplets. Amorphous carbon (a-C) coating of the beam screen surface is proposed to reduce electron cloud production, thereby minimising its dissipated power. To validate this solution, the COLDEX experiment has been re-commissioned. Such equipment mimics the performance of the LHC cold bore and beam screen cryogenic vacuum system in presence of LHC beams in the Super Proton Synchrotron (SPS). The main objective of the study is the performance evaluation of a-C coatings while operating the beam screen in the 10 to 60 K temperature range and cold bore below 3 K. This paper reviews the status of COLDEX and the results obtained during its first experimental runs.

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WEPHA011

Photodesorption and Electron Yield Measurements of Thin Film Coatings for Future Accelerators

vacuum, electron, photon, solenoid

3123

R. Kersevan, M. Ady, P. Chiggiato
CERN, Geneva, Switzerland
T. Honda, Y. Tanimoto
KEK, Tsukuba, Japan

The performance of future accelerators could be limited by electron cloud phenomena and high photodesorption yields. For such a reason, the study of secondary electron and photodesorption yields of vacuum materials is essential. The eradication or mitigation of both secondary electron and molecule desorption could strongly reduce the beam scrubbing time and increase the availability of nominal beams for experiments. Surface modifications with the desired characteristics can be achieved by thin-film coatings, in particular made of amorphous carbon and non-evaporable getters (NEG). In the framework of a new collaboration, several vacuum chambers have been produced, and different coatings on each of them have been applied. The samples were then irradiated at KEK’s Photon Factory with SR light of 4 keV critical energy during several days, allowing the measurement of the photodesorption yield as a function of the photon dose. This paper presents the experiment and briefly summarizes the preliminary photodesorption and photoelectron yield data of different coatings. The results can be used for future machine design with similar conditions, such as the FCC-hh.

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WEPHA016

Experimental Setups to Determine the Damage Limit of Superconducting Magnets for Instantaneous Beam Losses

proton, superconducting-magnet, injection, simulation

3138

V. Raginel, B. Auchmann, R. Schmidt, D. Schoerling, A.P. Verweij, D. Wollmann
CERN, Geneva, Switzerland

The damage mechanism of superconducting magnets due to the direct impact of high intensity particle beams is not well understood. Obvious candidates for upper bounds on the damage limit are overheating of insulation, and melting of the conductor. Lower bounds are obtained by the limits of elasticity in the conductor, taking into account dynamic effects (elastic stress waves). The plastic regime in between these two bounds will lead to differential thermal stress between the superconductor and stabilizer, which may lead to a permanent degradation of the magnet. An improved understanding of these mechanisms is required especially in view of the planned increase in brightness of the beams injected into the LHC and of the future High Luminosity-LHC [2] and Future Circular Collider (FCC). In this paper the plans for room temperature damage tests on critical parts of superconducting magnets and the strategy to test their damage levels at 4.3 K in the HiRadMat facility at CERN , using a 440 GeV proton beam generated by the Super Proton Synchrotron (SPS), is presented. Moreover the status of numerical simulations using FLUKA and multi-physics FEM code (ANSYS) to assess the different effect and the irradiation of the proposed experimental setup in preparation of the test is shown.

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WEPHA017

Qualification of the Bypass Continuity of the Main Dipole Magnet Circuits of the LHC

dipole, operation, controls, cryogenics

3141

S. Rowan, B. Auchmann, K. Brodzinski, Z. Charifoulline, B.I. Panev, F. Rodriguez-Mateos, I. Romera, R. Schmidt, A.P. Siemko, J. Steckert, H. Thiesen, A.P. Verweij, G.P. Willering
CERN, Geneva, Switzerland
H. Pfeffer
Fermilab, Batavia, Illinois, USA

The copper-stabilizer continuity measurement (CSCM) was devised in order to attain complete electrical qualification of all busbar joints, lyres, and the magnet bypass connections in the 13~kA circuits of the LHC. A CSCM is carried out at 20 K, i.e., just above the critical temperature, with resistive magnets. The circuit is then subject to an incremental series of controlled powering cycles, ultimately mimicking the decay from nominal current in the event of a magnet quench. A type test to prove the validity of such a procedure was carried out with success in April 2013, leading to the scheduling of a CSCM on all main dipole circuits up to and including 11.1 kA, i.e., the current equivalent of 6.5 TeV operation. This paper details the procedure, with respect to the type test, as well as the results and analyses of the LHC-wide qualification campaign.

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WEPTY012

Multiple Scattering Effects of a Thin Beryllium Window on a Short, 2 nC, 60 MeV Bunched Electron Beam

scattering, simulation, vacuum, emittance

3280

E.E. Wisniewski, M.E. Conde, W. Gai, G. Ha, J.G. Power
ANL, Argonne, Illinois, USA
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: U.S. Dept of Energy Office of Science under contract number DE-AC02-06CH11357.
The Argonne Wakefield Accelerator 75 MeV drive beamline at Argonne National Laboratory has as its electron source a Cesium telluride photocathode gun with a vacuum requirement on the order of 10^-10 torr. In conflict with this, the experimental program at AWA sometimes requires beamline installation of experimental structures which due to materials and/or construction cannot meet the stringent vacuum requirement. One solution is to sequester these types of structures inside a separate vacuum chamber and inject the beam through a thin Beryllium window. The downside is that multiple scattering effects degrade the beam quality to some degree which is not well-known. This study was done in an effort to better understand and predict the multiple scattering effects of the Be thin window, particularly on the beam transverse size. The results of measurements are compared with GEANT4 Monte Carlo simulations via G4beamline and analytical calculations via GPT.

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WEPTY015

Examination of Beryllium under Intense High Energy Proton Beam at CERN's HiRadMat Facility

target, proton, Windows, instrumentation

3289

K. Ammigan, B.D. Hartsell, P. Hurh, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
A.R. Atherton
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
M. Butcher, M. Calviani, M. Guinchard, R. Losito
CERN, Geneva, Switzerland
O. Caretta, T.R. Davenne, C.J. Densham, M.D. Fitton, P. Loveridge, J. O'Dell
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
V.I. Kuksenko, S.G. Roberts
University of Oxford, Oxford, United Kingdom

Funding: Work supported by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
Beryllium is extensively used in various accelerator beam lines and target facilities as material for beam windows, and to a lesser extent, as secondary particle production targets. With increasing beam intensities of future accelerator facilities, it is critical to understand the response of beryllium under extreme conditions to avoid compromising particle production efficiency by limiting beam parameters. As a result, the planned experiment at CERN’s HiRadMat facility will take advantage of the test facility’s tunable high intensity proton beam to probe and investigate the damage mechanisms of several grades of beryllium. The test matrix will consist of multiple arrays of thin discs of varying thicknesses as well as cylinders, each exposed to increasing beam intensities. Online instrumentations will acquire real time temperature, strain, and vibration data of the cylinders, while Post-Irradiation-Examination (PIE) of the discs will exploit advanced microstructural characterization and imaging techniques to analyze grain structures, crack morphology and surface evolution. Details on the experimental design, online measurements and planned PIE efforts are described in this paper.

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WEPTY016

RF Modeling of a Helical Kicker for Fast Chopping

kicker, impedance, simulation, linac

3293

M.H. Awida, A.Z. Chen, T.N. Khabiboulline, G.W. Saewert, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

High intensity proton particle accelerators that supports several simultaneous physics experiments requires sharing the beam. A bunch by bunch beam chopper system located after the Radio Frequency Quadrupole (RFQ) is required in this case to structure the beam in the proper bunch format required by the several experiments. The unused beam will need to be kicked out of the beam path and is disposed in a beam dumb. In this paper, we report on the RF modeling results of a proposed helical kicker. Two beam kickers constitutes the proposed chopper. The beam sequence is formed by kicking in or out the beam bunches from the streamline. The chopper was developed for Project X Injection Experiment (PXIE).

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WEPTY044

Phase Transients in the Higher-Harmonic RF Systems For the ALS-U Proposal

simulation, impedance, beam-loading, synchrotron

3372

J.M. Byrd, S. De Santis, T.H. Luo, C. Steier
LBNL, Berkeley, California, USA

Funding: This work was supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under U.S. Department of Energy Contract No. DE-AC02-05CH11231.
The ALS upgrade proposal (ALS-U) requires lengthening the bunch by a factor of at least four in order to increase the beam lifetime to acceptable values. Due to the presence of gaps in the fill pattern, required by the injection/extraction kicker system, the beam-induced voltage in the passive, normal-conducting, cavities which we plan to use is not constant over the length of a bunch train. We present our result on the optimal tuning of the harmonic cavities to obtain the best lifetime increase, including the effects of strongly non-gaussian bunch shapes and wakefield distortions of the potential well.

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WEPWI042

A Table-Top Alpha-Magnet

operation, vacuum, power-supply, collimation

3584

A.V. Smirnov, R.B. Agustsson, T.J. Campese, Y.C. Chen, J.J. Hartzell, F.H. O'Shea, E. Spranza
RadiaBeam, Santa Monica, California, USA

Funding: Department of Energy, contract# DE- SC-FOA-0000760
A compact electromagnetic alpha-magnet design, engineering, and operation are presented. Initially the magnet has been designed for a low-energy, laser-free, coherent Cherenkov THz-sub-THz source. The source is designed and engineered in RadiaBeam in collaboration with ANL and integrated into the Injector Test Stand (ITS) of the Advanced Photon Source. The magnet having 15 cm depth, 14” height, and up to 4 T/m gradient features a rectangular yoke, two on-axis coils, and substantially truncated, partially non-hyperbolic poles. The tapered vacuum chamber for the magnet includes a motorized scraper and means of optical control. The novel and inexpensive design can be applied in relatively small, a few MeV facilities, where weight and dimensions are limited including free electron lasers, far infrared sources, inverse Compton sources of ultra-bright hard X-rays, as well as beam instrumentation for microbunching and phase-space manipulation (e.g., magnetic compression combined with round-to-flat beam transformation).

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WEPWI049

Commissioning of the 112 MHz SRF Gun and 500 MHz Bunching Cavities for the CeC PoP Linac

gun, SRF, bunching, electron

3597

S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, V. Litvinenko, G. Narayan, P. Orfin, I. Pinayev, T. Rao, J. Skaritka, K.S. Smith, R. Than, J.E. Tuozzolo, E. Wang, Q. Wu, B. P. Xiao, W. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA
S.A. Belomestnykh, I. Ben-Zvi, V. Litvinenko, T. Xin
Stony Brook University, Stony Brook, USA
P.A. McIntosh, A.J. Moss, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
The Coherent electron Cooling Proof-of-Principle (CeC PoP) experiment at BNL includes a short electron linac. During Phase I a 112 MHz superconducting RF photoemission gun and two 500 MHz normal conducting bunching cavities were installed and commissioned. The paper describes the Phase I linac layout and presents commissioning results for the cavities and associated RF, cryogenic and other sub-systems.

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THPF010

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

target, cryogenics, simulation, ion

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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THPF037

Upgrade of the LNS Superconducting Cyclotron

extraction, ion, cyclotron, 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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THPF043

Preliminary Studies of Laser-assisted H⁻ Stripping at 400 MeV

laser, injection, proton, operation

3795

P.K. Saha, H. Harada, M. Kinsho, T. Maruta, K. Okabe, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
T.V. Gorlov
ORNL, Oak Ridge, Tennessee, USA
Y. Irie
KEK, Ibaraki, Japan

Conventional H⁻ stripping injection by using solid stripper foils in high intensity accelerators has many limitations concerning foil scattering beam losses, short lifetime of the foil including unexpected and rapid foil failure due to overheating of the foil. It is not only an issue for reliable machine operation but also for facility maintenance. In the 3-GeV RCS of J-PARC, the residual radiation level is extremely high not only near the injection area but also the used foil itself including the foil holder even at the present operation with one third of the designed 1 MW beam power. As an alternate method, later-assisted stripping of 1 GeV H⁻ beam has been intensively studied at SNS in Oak Ridge. The preparation for the next experiment is underway to demonstrate a three orders of magnitude improvement as compared to the earlier experiment. It is important to extend these studies for the lower H⁻ beam energies. In the same framework as in the SNS, laser stripping for the J-PARC H⁻ beam energy of 400 MeV has been studied in the present work. The real challenges and feasibilities at this lower energy are discussed in this paper.

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THPF045

Simulation Study of Muon Acceleration using RFQ for a New Muon g-2 Experiment at J-PARC

rfq, simulation, acceleration, emittance

3801

Y. Kondo, K. Hasegawa
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan
T. Mibe, M. Otani, N. Saito
KEK, Tsukuba, Japan

A new muon g-2 experiment is planning at J-PARC. In this experiment, ultra cold muons will be generated and accelerated using a linear accelerator. As the first accelerating structure, an RFQ will be used. We are planning to use a spare RFQ of the J-PARC linac for the first acceleration test. We present simulation studies of this acceleration test. A design study of a muon dedicated RFQ is also shown.

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THPF107

Quality and Stability Studies of the Beams in the ELENA Ring Transfer Lines

quadrupole, antiproton, simulation, lattice

3966

J.R. Hunt, O. Karamyshev, J. Resta-López, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
J.R. Hunt, O. Karamyshev, J. Resta-López, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Work supported by the EU under Grant Agreement 624854 and the STFC Cockcroft Institute core Grant No. ST/G008248/1.
The Extra Low ENergy Antiproton (ELENA) ring will provide seven different experiments at CERN with cooled beams of low energy (~100 keV) antiprotons. As a result, a system of transfer lines is being designed to ensure that each experiment receives a beam with its required properties. In this contribution, particle tracking simulations using MADX are performed to explore the effects on the beam quality and orbit stability of different lattice imperfections, such as element misalignment, electric field and matching errors. The tolerances on the actual values of these quantities are obtained as a guide for the construction of the transfer lines.

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THPF120

Design of the LBNF Beamline

target, proton, shielding, operation

3992

V. Papadimitriou, R. Andrews, J. Hylen, T.R. Kobilarcik, G.E. Krafczyk, A. Marchionni, C.D. Moore, P. Schlabach, S. Tariq
Fermilab, Batavia, Illinois, USA

Funding: Work supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The Long Baseline Neutrino Facility (LBNF) will utilize a beamline located at Fermilab to carry out a compelling research program in neutrino physics. The facility will aim a wide band neutrino beam toward underground detectors placed at the SURF Facility in South Dakota, about 1,300 km away. The main elements of the facility are a primary proton beamline and a neutrino beamline. The primary proton beam (60-120 GeV) will be extracted from the MI-10 section of Fermilab’s Main Injector. Neutrinos are produced after the protons hit a solid target and produce mesons which are subsequently focused by magnetic horns into a 204m long decay pipe where they decay into muons and neutrinos. The parameters of the facility were determined taking into account the physics goals, spacial and radiological constraints and the experience gained by operating the NuMI facility at Fermilab. The initial proton beam power is expected to be 1.2 MW, however the facility is designed to be upgradeable to 2.4 MW. We discuss here the design status and the associated challenges as well as plans for improvements before baselining the facility.

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THPF121

Out of Time Beam Extinction in the Mu2e Experiment

dipole, simulation, proton, extraction

3996

E. Prebys, S.J. Werkema
Fermilab, Batavia, Illinois, USA

Funding: This project is supported by the US Department of Energy under contract No. De-AC02-07CH11359 .
The Mu2e Experiment at Fermilab will search for the conversion of a muon to an electron in the field of an atomic nucleus with unprecedented sensitivity. The experiment requires a beam consisting of proton bunches approximately 200ns FW long, separated by 1.7 microseconds, with no out-of-time protons at the 10^-10 fractional level. Satisfying this "extinction" requirement is very challenging. Simulations show that the formation of the bunches will result in an extinction of roughly 10^-5. The remaining extinction will be accomplished by a system of resonant magnets and collimators, configured such that only in-time beam is delivered to the experiment.

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THPF122

The Status of MICE Step IV

solenoid, emittance, detector, collider

4000

D. Rajaram
Fermilab, Batavia, Illinois, USA
V.C. Palladino
INFN-Napoli, Napoli, Italy

Funding: SFTC, DOE, NSF, INFN, CHIPP and more
Muon (μ) beams of low emittance provide the basis for the intense, well-characterised neutrino beams of the Neutrino Factory and for lepton-antilepton collisions at energies of up to several TeV at the Muon Collider. The International Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling; the technique by which it is proposed to reduce the μ phase-space volume. In a cooling channel, the μ beam traverses a material (the absorber) in which it looses energy, then replaced longitudinally by RF cavities. The net effect is to reduce transverse emittance(transverse cooling). MICE is being constructed in a series of Steps. At Step IV, MICE will study the properties of liquid hydrogen and lithium hydride that affect cooling. A solenoidal spectrometer will measure emittance up and downstream of the absorber vessel, where a focusing coil will focus muons. The construction of Step IV at RAL is well advanced towards scheduled completion early in 2015. Its status will be described together with a summary of the performance of the principal components. Plans for the commissioning and operation and the Step IV measurement programme will be described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF122

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THPF128

Accelerator Physics and Technology Research Toward Future Multi-MW Proton Accelerators

proton, target, electron, SRF

4019

V.D. Shiltsev, P. Hurh, A. Romanenko, A. Valishev, R.M. Zwaska
Fermilab, Batavia, Illinois, USA

Funding: Fermi Research Alliance, LLC operates Fermilab under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
Recent P5 report indicated the accelerator-based neutrino and rare decay physics research as a centrepiece of the US domestic HEP program. Operation, upgrade and development of the accelerators for the near-term and longer-term particle physics program at the Intensity Frontier face formidable challenges. Here we discuss accelerator physics and technology research toward future multi-MW proton accelerators.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF128

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FRXB1

The DOE Long-Term Accelerator R&D Stewardship Program

laser, cyclotron, ion, 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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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-FRXB1

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FRXC2

The High Luminosity LHC Project

luminosity, operation, dipole, radiation

4096

O.S. Brüning
CERN, Geneva, Switzerland

This presentation reviews the status of the high luminosity LHC project, and highlights the main challenges from the technology and beam physics point of view. It will mention the outcome of the 2015 Cost and Schedule review for the HL-LHC project and summarizes the status of the high field quadrupole and crab cavity development.

Slides FRXC2 [7.951 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-FRXC2

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