THPB —  Poster Session   (13-Sep-12   16:00—18:00)

Paper	Title	Page
THPB002	Preliminary Study of Proton Beam Transport in a 10 MeV Dielectric Wall Accelerator	840
	J. Zhu, S. Chen, J. Deng, Y. Shen, J. Shi, W.D. Wang, L.S. Xia, H. Zhang, L.W. Zhang CAEP/IFP, Mainyang, Sichuan, People's Republic of China Y. Liu Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan, People's Republic of China
	Funding: Nuclear Energy Technology Development project; National Natural Science Foundation of China (11035004) A novel proton accelerator based on Dielectric Wall Accelerator (DWA) technology is being developed at Institute of Fluid Physics (IFP). The accelerating gradient will be 20 MV/m or even higher based on current high gradient insulator (HIG) performance. Theoretical study and numerical simulation of accelerating the proton beam to 10 MeV by virtual traveling wave method is presented in this paper. The beam dynamics under accelerating pulse with or without flattop is discussed.
THPB003	R&D Activities on High Intensity Superconducting Proton Linac at RRCAT	843
	S.C. Joshi, J. Dwivedi, P.D. Gupta, P.R. Hannurkar, P. Khare, P.K. Kush, G. Mundra, A. Puntambekar, S.B. Roy, P. Shrivastava RRCAT, Indore (M.P.), India
	Raja Ramanna Centre for Advanced Technology (RRCAT), Indore has taken up a program on development of 1 GeV high intensity superconducting proton linac for Spallation Neutron Source. This will require several multi-cell superconducting cavities operating at different RF frequencies. To start with, a number of single-cell prototype cavities at 1.3 GHz have been developed in high RRR bulk niobium. These single-cell cavities have exhibited high quality factor and accelerating gradients. Superconducting properties of niobium are being studied for varying composition of impurities and different processing conditions. Development activity on solid state RF amplifiers to power the SCRF cavities at various RF frequencies is being pursued. A building has been constructed to house the SCRF cavity fabrication and processing facility. To characterize SCRF cavity, a 2 K Vertical Test Stand is being set up including a 2 K cryostat, RF power supply and data acquisition system. Design activities for cryomodule and large 2 K cryostat for Horizontal Test Stand are also under progress. The paper will discuss the status of above R&D activities and infrastructure development at RRCAT.
THPB004	Current Status of the RAL Front End Test Stand (FETS) Project	846
	D.C. Plostinar, C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom S.M.H. Alsari, M. Aslaninejad, A. Kurup, J.K. Pozimski, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom J.J. Back University of Warwick, Coventry, United Kingdom G.E. Boorman, A. Bosco Royal Holloway, University of London, Surrey, United Kingdom M.A. Clarke-Gayther, D.C. Faircloth, S.R. Lawrie, A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom S. Jolly UCL, London, United Kingdom
	The UK proton accelerator strategy aims to develop a viable high power proton driver with applications including spallation neutrons, the neutrino factory and ADSR. An essential first ingredient, identified as one of the main UK R&D accelerator projects, is the Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL), aimed at producing a high quality, high current, cleanly chopped H− beam. Through its component parts, FETS has triggered development of a high brightness, 60 mA H− ion source, a three-solenoid Low Energy Beam Transport line (LEBT), a 3 MeV four-vane Radio-Frequency Quadrupole (RFQ) and a Medium Energy Beam Transport line (MEBT) with a high speed chopper. The project is well advanced and when operational should be sufficiently versatile to explore a range of operating conditions. In this paper we present the current status of the construction, and plans for operation, experiments and future development.
THPB005	Front-End Linac Design and Beam Dynamics Simulations for MYRRHA	849
	C. Zhang, H. Klein, D. Mäder, H. Podlech, U. Ratzinger, A. Schempp, R. Tiede, M. Vossberg IAP, Frankfurt am Main, Germany
	Funding: Funded by the European Atomic Energy Community’s (Euratom) 7th Framework Programme under Grant Agreement n°269565. A 17MeV, 176MHz, and CW (Continuous Wave) proton linac is being developed as the front end of the driver accelerator for the MYRRHA facility in Mol, Belgium. Based on the promising preliminary design, further simulation and optimization studies have been performed with respect to code benchmarking, RFQ simulation using realistic LEBT output distributions, and an updated CH-DTL design with more detailed inter-tank configurations. This paper summarizes the new results.
THPB006	Post Acceleration of Laser-generated Proton Bunches by a CH-DTL	852
	A. Almomani, M. Droba, I. Hofmann, U. Ratzinger IAP, Frankfurt am Main, Germany
	Laser driven proton beam sources applying the TNSA process show interesting features in terms of energy and proton number per bunch. This makes them attractive as injectors into RF linacs at energies as high as 10 MeV or beyond. The combination shows attractive features like a very high particle number in a single bunch from the source and the flexibility and reliability of the rf linac to match the needs of a specified application. The approach aims on a very short matching section from the source target into the rf linac by one pulsed solenoid lens only. A crossbar H-type (CH - structure) is suggested because of its high acceleration gradient and efficiency at these beam energies. It is intended to realize the first cavity of the proposed CH - linac and to demonstrate the acceleration of a laser generated proton bunch within the LIGHT collaboration at GSI Darmstadt. Detailed beam and field simulations will be presented.
THPB007	A Pulsed Linac Front-end for ADS Applications	855
	U. Ratzinger, H. Podlech, A. Schempp, K. Volk IAP, Frankfurt am Main, Germany U. Hagen, O. Heid, T.J.S. Hughes Siemens AG, Erlangen, Germany H. Hoeltermann BEVATECH OHG, Offenbach/Main, Germany
	Quite a number of projects worldwide develop proton driver linacs for neutron sources and other accelerator driven systems. One trend is to use a high duty factor and superconducting cavities as much as possible. Alternatively, one can aim on short duty factor and count on a continuing rapid development of pulsed rf amplifiers based on power transistor technology. A 500 mA, 5 % duty factor layout of a proton injector is presented, consisting of a filament driven volume ion source, of a 150 keV transport section and of a 4 m long 162 MHz RFQ up to 2 MeV beam energy. Beam dynamics results as well as the technical design will be shown.
THPB008	A Coupled RFQ-IH Cavity for the Neutron Source FRANZ	858
	M. Heilmann, O. Meusel, D. Mäder, U. Ratzinger, A. Schempp, M. Schwarz IAP, Frankfurt am Main, Germany
	The Frankfurt neutron source FRANZ will deliver neutrons in the energy range from 1 to 500 keV with high pulsed intensities. A 2 MeV proton beam will produce protons via the 7Li(p,n)7Be reaction. The 175 MHz accelerator cavity consists of a 4-rod-RFQ coupled with an 8 gap interdigital H-type drift tube section, the total cavity length being 2.3m. The combined cavity will be powered by one RF amplifier to reduce investment and operation costs. The inductive power coupler will be at the RFQ part. The coupling into the IH - section is provided through a large aperture - mainly inductively. By CST - MWS - simulations as well as by an RF - model the voltage tuning along the cavity was investigated, and with special care the balance between both cavity sections. A first set of RFQ electrodes should allow to reach beam currents up to 50 mA in cw operation: The beam is pulsed with 100 ns, 250 kHz, while the cavity has to be operated cw due to the high rep. rate. The layout of the cavity cooling aims on a maximum accessible heat load of 200 kW.
THPB009	Status of CH Cavity and Solenoid Design of the 17 MeV Injector for MYRRHA	861
	D. Mäder, H. Klein, H. Podlech, U. Ratzinger, C. Zhang IAP, Frankfurt am Main, Germany
	Funding: This work has been supported by the EU (FP7 MAX contract number 269565) The multifunctional subcritical reactor MYRRHA (Multi-purpose hybrid research reactor for high-tech applications) will be an accelerator driven system (ADS) located in Mol (Belgium). The first accelerating section up to 17 MeV is operated at 176 MHz and consists of a 4-rod-RFQ followed by two room temperature CH cavities with integrated triplet lenses and four superconducting CH structures with intertank solenoids. Each room temperature CH cavity provides about 1 MV effective voltage gain using less than 30 kW of RF power. The superconducting resonators have been optimized for electric peak fields below 30 MV/m and magnetic peak fields below 30 mT. For save operation of the superconducting resonators the magnetic field of the intertank solenoids has to be well shielded towards the CH cavity walls. Different coil geometries have been compared to find the ideal solenoid layout.
THPB010	Progress in the Construction of Linac4 at CERN	864
	M. Vretenar, L. Arnaudon, P. Baudrenghien, G. Bellodi, C. Bertone, Y. Body, J.C. Broere, O. Brunner, M.C.L. Buzio, C. Carli, J.-P. Corso, J. Coupard, A. Dallocchio, N. Dos Santos, J.-F. Fuchs, A. Funken, R. Garoby, F. Gerigk, L. Hammouti, K. Hanke, J. Hansen, I. Kozsar, J.-B. Lallement, J. Lettry, A.M. Lombardi, L.A. Lopez Hernandez, C. Maglioni, S.J. Mathot, B. Mikulec, D. Nisbet, M.M. Paoluzzi, B. Puccio, U. Raich, S. Ramberger, F. Roncarolo, C. Rossi, N. Schwerg, R. Scrivens, G. Vandoni, J. Vollaire, R. Wegner, S. Weisz, Th. Zickler CERN, Geneva, Switzerland
	As first step of the LHC luminosity upgrade program CERN is building a new 160 MeV H¯ linear accelerator, Linac4, to replace the ageing 50 MeV Linac2 as injector to the PS Booster (PSB). Linac4 is an 86-m long normal-conducting linac made of a 3 MeV injector followed by 22 accelerating cavities of three different types. The general service infrastructure has been installed in the new tunnel and surface building and its commissioning is progressing; high power RF equipment is being installed in the hall and installations in the tunnel will start soon. Construction of the accelerator parts is in full swing involving industry, the CERN workshops and a network of international collaborations. The injector section including a newly designed and built H¯ source, a 3-m long RFQ and a chopping line is being commissioned in a dedicated test stand. Beam commissioning of the linac will take place in steps of increasing energy between 2013 and 2014. From end of 2014 Linac4 could deliver 50 MeV protons in case of Linac2 failure, while 160 MeV H¯ could be injected into the PSB from end of 2015; the exact start of the LHC shut-down required for connection will be coordinated with its experiments.
THPB011	Linac4 45 keV Proton Beam Measurements	867
	G. Bellodi, V.A. Dimov, L.M. Hein, J.-B. Lallement, A.M. Lombardi, O. Midttun, R. Scrivens CERN, Geneva, Switzerland P.A. Posocco Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Linac4 is a 160 MeV normal-conducting H− linear accelerator, which will replace the 50 MeV proton Linac (Linac2) as injector for the CERN proton complex. Commissioning of the low energy part - H− source, a 45 keV Low Energy Beam Transport line (LEBT), a 3 MeV RFQ and a Medium Energy Beam Transport (MEBT) line - will start in fall 2012 on a dedicated test stand installation. In preparation to this, preliminary measurements were taken in the past few months using a 45 keV proton source and a temporary LEBT setup, with the aim of characterising the output beam by comparison with simulations. This also allowed a first verification of the diagnostics instrumentation and acquisition software tools. Measurements of beam profile, emittance and intensity were taken after the source, after the first and after the second LEBT solenoids respectively. Particle distributions were reconstructed from emittance scans and used as input to simulation studies of the beam transport through the line. Comparison of the results with the measurements allowed an experimental validation of the LEBT (in terms of misalignments and calibration points) and qualification of the beam at the source output.
THPB012	High Resolution Emittance Measurements at SNS Front End	870
	A.P. Zhukov, A.V. Aleksandrov 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. Spallation Neutron Source (SNS) linac accelerates an H− beam from 2.5MeV up to 1GeV. Recently the emittance scanner in the MEBT (2.5 MeV) was upgraded. In addition to the slit - harp measurement we now can use a slit installed on the same actuator as the harp. In combination with a faraday cup located downstream in DTL part of the linac it represents a classical slit-slit emittance measurement device. While a slit – slit scan takes much longer time, it is immune to harp related problems such as wire cross talk and thus looks promising for accurate halo measurements. Time resolution of the new device seems to be sufficient to estimate amount of the beam in the chopper gap (the scanner is downstream of the chopper) and probably measure its emittance. The paper describes initial measurements with new device and some model validation data.
THPB013	Diagnostics Tools for Beam Halo Investigation in SNS Linac	873
	A.V. Aleksandrov, W. Blokland, Y. Liu, C.D. Long, A.P. Zhukov ORNL, Oak Ridge, Tennessee, USA
	Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. Uncontrolled beam loss is the major concern in operation of a high intensity hadron linac. A low density cloud of particles with large oscillation amplitudes, so called halo, can form around the dense regular beam core. This halo can be direct or indirect cause of beam loss. There is an experimental evidence of halo growing in SNS linac and limiting further reduction of beam loss. A set of tools is being developed for detecting of the halo and investigating its origin and dynamics. The set includes high resolution emittance measurements in the injector, laser based emittance measurements at 1 GeV, and high resolution profile measurements along the linac. We will present our experience with useful measurement techniques and data analysis algorithms as well as current understanding of the halo dynamics in SNS linac.
THPB014	Lattice Design and Beam Dynamics Studies for Project X	876
	N. Solyak, J.-P. Carneiro, V.A. Lebedev, J.-F. Ostiguy, A. Saini Fermilab, Batavia, USA
	Fermilab is developing Project-X, a high intensity superconducting H− machine for high energy physics experiments. The first stage is 1 mA average, 3 GeV linac operating in CW mode. Its front-end comprises a LEBT section with magnetic focusing and pre-chopping, a 162.5 MHz RFQ and ~10 m long MEBT section which includes a high bandwidth, bunch-by-bunch capable chopper. The latter extracts, out of a nominal 5 mA peak 162.5 MHz train, and arbitrary bunch structure able to meet the requirements of different experiments. Acceleration from 2.1 MeV to 3 GeV is accomplished through five families of SRF cavities operating at three frequencies: Half-wave resonators (162.5 MHz), spoke cavities (two families at 325 MHz) and elliptical cavities (two families at 650 MHz). In this contribution, we present the status of the CW linac lattice design and results from recent beam physics studies.
THPB015	Performance of Ferrite Vector Modulators in the LLRF system of the Fermilab HINS 6-Cavity Test	879
	P. Varghese, B.W. Barnes, B. Chase, E. Cullerton, C.C. Tan Fermilab, Batavia, USA
	The High Intensity Neutrino Source (HINS) 6-cavity test is a part of the Fermilab HINS Linac R&D program for a low energy, high intensity proton/H− linear accelerator. One of the objectives of the 6-cavity test is to demonstrate the use of high power RF Ferrite Vector Modulators(FVM) for independent control of multiple cavities driven by a single klystron. The beamline includes an RFQ and six cavities. The LLRF system provides a primary feedback loop around the RFQ and the distribution of the regulated klystron output is controlled by secondary learning feed-forward loops on the FVMs for each of the six cavities. The feed-forward loops provide pulse to pulse correction to the current waveform profiles of the FVM power supplies to compensate for beam-loading and other disturbances. The learning feed-forward loops are shown to successfully control the amplitude and phase settings for the cavities well within the 1 % and 1 degree requirements specified for the system.
THPB016	Concept: Low Energy, Low Intensity NF from ProjectX	882
	M. Popovic Fermilab, Batavia, USA
	This note describes the concept of a Low Luminosity Low Energy Neutrino Factory (L3ENF) using a Project X pulsed, or CW, Linac at 8GeV. By collecting pis and mus with energy ~1 GeV, and accelerating them to 10 GeV, it is possible to store ~1020 mus per year. Most of the concepts suggested here can be tested using the Booster beam, Recycler, Antiproton Target Station, the Main Injector and the Tevatron. Once the VLENF Muon Storage Ring is built, components needed for L3ENF could be used in experiments before Project X completion.
THPB017	A Concept: 8GeV CW Linac, Staged Approach	885
	M. Popovic, J.-F. Ostiguy Fermilab, Batavia, USA
	This note describes a concept of CW Proton Linac on the Fermilab site. With exception of RFQ the linac is based on superconducting technology. Based on the output, energy is segmented in three parts, 1GeV, 3GeV and 8GeV. It is located near existing Fermilab Proton Source with the intention that each section of the linac can be used as soon as it is commissioned. The whole design is based on the designs suggested for the Proton Driver and ProjectX. The suggested site and linac segmentation allows for the construction to start immediately. Additional benefits come from the fact that the present linac (the oldest machine in Fermilab complex) is replaced and existing Proton Source’s functionality is preserved for the future.
THPB020	Annular-ring Coupled Structure for the Energy Upgrade of the J-PARC Linac	888
	H. Ao, H. Asano, N. Ouchi, J. Tamura JAEA/J-PARC, Tokai-mura, Japan F. Naito, K. Takata KEK, Ibaraki, Japan
	The linac of Japan Proton Accelerator Research Complex (J-PARC), which is an injector to the synchrotron, comprises a 3-MeV RFQ, 50-MeV DTLs and the 181-MeV Separated-type DTLs. In order to increase the beam power of the synchrotron, the task of the 400-MeV energy upgrade of the linac started from March 2009. The tanks of the Annular-ring Coupled Structure (ACS) linac, RF sources, beam monitors and utilities are in production. Although some peripheral components of the ACS linac are prepared previously, the all ACS tanks will be installed and conditioned for 4 months from July 2013. Beam commissioning of the 400-MeV linac is scheduled to begin in October and expected to finish at the end of November 2013. In this paper, we present the current status of the energy upgrade and some R&D results for new equipment for ACS linac.
THPB021	Recovery Efforts from the Tohoku Earthquake and Energy Upgrade Preparation of the Beam Transport from the J-PARC Linac to the 3-GeV Synchrotron	891
	J. Tamura, H. Ao, H. Asano, T. Morishita, N. Ouchi JAEA/J-PARC, Tokai-mura, Japan Y. Sawabe MELCO SC, Tsukuba, Japan
	In 2013, the beam energy of the Japan Proton Accelerator Research Complex (J-PARC) linac is going to be increased from 181-MeV to 400-MeV by adding the annular-ring coupled structure (ACS) at the downstream of the 191-MeV drift tube linac. To install and operate all the ACS cavities in only five months of the energy upgrade shutdown in 2013, we decided to replace and upgrade all the related component of the beam line (cables, magnet power supplies and vacuum control systems) for the 400-MeV operation, in the period of the recovery from the Tohoku Earthquake which caused not negligible damage to the J-PARC accelerator facilities. The present beam line is operated by using some part of the 400-MeV componets. In this paper, the recovery of the beam transport, the present status and the future tasks of the beam energy upgrade will be presented.
THPB022	Beam Phase Measurement for PEFP Linear Accelerator	894
	H.S. Kim, Y.-S. Cho, J.-H. Jang, H.-J. Kwon, J.Y. Ryu, K.T. Seol, Y.-G. Song KAERI, Daejon, Republic of Korea
	Funding: Works supported by the Ministry of Education, Science and Technology of Korean Government. According to the commissioning plan of the PEFP proton linac, an accurate measurement of beam phase is essential, especially for setting up the RF operating parameters of DTL. Beam position monitors (BPMs) installed between DTL tanks can provide information about the beam phase as well as about the beam transverse position. By using a BPM as a beam phase monitor, beam phase can be measured without additional devices on the linac or the beam line. The signals from 4 electrodes in the BPM can be summed by using a 4-way RF combiner, by which the effect of the transverse beam offset on the phase measurement can be eliminated. The combined BPM signal (350 MHz) is mixed with LO signal (300 MHz) and down-converted to IF signal (50 MHz), then fed into the signal processing unit, where the phase information is extracted by using IQ demodulation method with a sampling frequency of 40 MHz. In this paper, the beam phase measurement system and signal processing scheme will be presented.
THPB023	Linac Construction for China Spallation Neutron Source	897
	S. Fu, J. Li, H.C. Liu, H.F. Ouyang, X. Yin IHEP, Beijing, People's Republic of China
	Construction of China Spallation Neutron Source(CSNS) has been launched in September 2011. CSNS accelerator will provide 100kW proton beam on a target at beam energy of 1.6GeV. It consists of an 80MeV H− linac and 1.6GeV rapid cycling synchrotron. Based on the prototyping experience, CSNS linac, including the front end and four DTL tanks, has finalized the design and started procurement. In this paper, we will first present an outline of the CSNS accelerator in its design and construction plan. Then the major prototyping results of the linac will be presented. Finally the linac construction progress in recent will be updated.
THPB024	Main Linac Physics Design Study of the C-ADS Project	900
	F. Yan, Z. Li, C. Meng, J.Y. Tang IHEP, Beijing, People's Republic of China
	Funding: The pilot special funds of Chinese Academy of Science The Chinese ADS project is proposed to build a 1000MW Accelerator Driven sub-critical System before 2032. The accelerator will be operating on CW mode with 10mA average current and the final energy is 1.5GeV. The whole linac are composed of two major sections: the Injector section and the main linac section. There are two different schemes for the Injector section. InjectorI is basing on 325MHz RFQ and superconducting spoke cavities and Injector II is basing on 162.5MHz RFQ and superconducting HWR cavities. The main linac design will be different for different Injector choice. If Injector II scheme is adopted, the main linac bunch current will be doubled. In this paper we studied the main linac design basing on InjectorII scheme. The design principles and the priliminary design results is presented.
THPB025	325 MHz CW Room Temperature High Power Bunching Cavity for the China ADS MEBT1	903
	S. Pei, X. Li, H.F. Ouyang, J.R. Zhang IHEP, Beijing, People's Republic of China
	Two room temperature high power bunching cavities are required to be located in the ADS MEBT1 section. Double re–entrant nose cone geometry has been adopted as the type of the bunching cavity for its simplicity, higher shunt impedance and lower risk of multipacting. SUPERFISH is used to optimize the internal dimensions of the bunching cavity, then the RF–thermal–structural–RF coupled analysis were carried out in ANSYS to obtain the preliminary mechanical design, the layout of the cooling channels is optimized to suppress the frequency shift as much as possible. The cavity was specially designed to have the capability to withstand the 1 atm air pressure effect. In addition, the main dimensions of the coupler and tuner are also estimated. *peisl@ihep.ac.cn
THPB026	The Beam Commissioning Plan of Injector II in C-ADS	906
	Z.J. Wang, Y. He, H. Jia, C. Li, S.H. Liu, W. Wu, X.B. Xu, B. Zhang, H.W. Zhao IMP, Lanzhou, People's Republic of China
	The design work of the Injector II, which is 10 MeV proton linac, in C-ADS project is being finished and some key elements are being fabricated. Now it is necessary to definite the operation mode of beam commissioning, including the selection of the beam current, pulse length and repetition frequency. Also the beam commissions plan should be specified. The beam commissions procedures is simulated with t-mode code GPT. In this paper, the general beam commissioning plan of Injector II in CIADS and simulation results of commissions procedures are presented.
THPB027	Progress of one of 10 MeV superconducting proton linear Injectors for C-ADS	909
	Y. He, J. Meng, A. Shi, Z.J. Wang, J.X. Wu, W. Wu, H.S. Xu, Z. Xu, B. Zhang, J.H. Zhang, S.H. Zhang, Z.M. Zhang, H.W. Zhao, Z.Z. Zhou IMP, Lanzhou, People's Republic of China D. Li LBNL, Berkeley, California, USA
	A 10 MeV superconducting proton linac is being design and constructing at Institute of Modern Physics (IMP) of Chinese Academy of Sciences (CAS). This proton linac is one of two injectors for Chinese ADS project. It is to validate one of concepts for C-ADS front end, to demonstrate the low beta acceleration, to minimize the risk of key technoledges within the Reference Design. It consists of a 2.1 MeV RFQ and two cryomodules hosting 8 HWR cavities. The basic frequecy is 162.5 MHz. The physical design of linac and the progess of prototypes for solid state amplifiers, superconducting solenoids, supercondecting HWRs, ion source, and RFQ are presented in the paper.
THPB028	The ESS Low Energy Beam Transport Line Design	912
	L. Neri, L. Calabretta, A.C. Caruso, L. Celona, S. Gammino, A. Longhitano, D. Mascali INFN/LNS, Catania, Italy B. Cheymol, A. Ponton ESS, Lund, Sweden
	The linear accelerator of the European Spallation Source (ESS) will deliver proton beams of 50 mA and 2.5 GeV onto the 5 MW neutron production target. The Proton Source for ESS (PS-ESS) [1] is based on the experience of TRIPS and VIS developed at LNS Catania [2,3]. A two solenoid Low Energy Beam Transport (LEBT) is foreseen to match the beam into the first acceleration stage, the Radio-Frequency Quadrupole (RFQ) [4]. Beam production means also detailed characterization of produced beam, with this scope the LEBT houses many instrumentation devices and use different techniques that will be described in this work. The LEBT will be also equipped with an electrostatic chopper in order to remove the unwanted part of the beam pulse during the natural rise and fall times of the ion source. Beam dynamics calculations of the LEBT have been carried out considering also the Space Charge Compensation (SCC) produced by the interaction of the beam with the residual gas, and its effect on beam transport and chopping. Particular emphasis has been put on the evaluation of the beam transient behavior, due to the chopping process, at the entrance of the RFQ, results of the study are presented in this paper.
THPB029	The ESS RFQ Beam Dynamics Design	915
	A. Ponton ESS, Lund, Sweden
	to be added
THPB030	DTL Design for ESS	918
	M. Comunian, F. Grespan, A. Pisent INFN/LNL, Legnaro (PD), Italy R. De Prisco Lund University, Lund, Sweden M. Eshraqi ESS, Lund, Sweden P. Mereu INFN-Torino, Torino, Italy
	In the present design of the European Spallation Source (ESS) accelerator, the Drift Tube Linac (DTL) will accelerate a proton beam of 50 mA pulse peak current from 3 to 80 MeV. It is designed to operate at 352.2 MHz, with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period). Permanent magnet quadrupoles (PMQs) are used as focusing elements in a FODO lattice scheme, which leaves space for steerers and diagnostics . In this paper beam dynamics studies and preliminary RF design are shown, including constraints in terms of quadrupole dimensions, total length, field stability, RF power, peak electric field.
THPB031	Status Report on the French High-intensity Proton Injector Project at SACLAY (IPHI)	921
	B. Pottin, M. Desmons, A. France, R. Gobin, O. Piquet CEA/DSM/IRFU, France
	The construction of IPHI (High Power Proton Accelerator) is in its final step of installation. The high intensity light ion source (SILHI) has been built first to produce regularly CW high intensity (over 100 mA) proton beams. The low energy front end of IPHI is based on a 352 MHz, 6 m long Radiofrequency Quadrupole (RFQ) cavity. The RFQ will accelerate beam up to 100 mA with energy up to 3 MeV. A diagnostics line has been designed to measure all the main characteristics of the beam at the RFQ output. In this paper we will present the status for the main components of the injector, in particularly the RFQ fabrication and the RF power facilities.
THPB032	Beam Dynamics Design Aspects for a Proposed 800 MeV H− ISIS Linac	924
	D.C. Plostinar, C.R. Prior, G.H. Rees STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	Several schemes have been proposed to upgrade the ISIS Spallation Neutron Source at Rutherford Appleton Laboratory (RAL). One scenario is to develop a new 800 MeV, H− linac and a ~3 GeV synchrotron, opening the possibility of achieving several MW of beam power. In this paper the design of the 800 MeV linac is outlined with an emphasis on the beam dynamics design philosophy. The linac consists of a 3 MeV Front End similar to the one now under construction at RAL (the Front End Test Stand -FETS). Above 3 MeV, a 324 MHz DTL will be used to accelerate the beam up to ~75 MeV. At this stage a novel collimation system will be added to remove the halo and the far off-momentum particles. To achieve the final energy, a 648 MHz superconducting linac will be employed using three families of elliptical cavities with transition energies at ~196 MeV and ~412 MeV.
THPB034	Status of the FAIR 70 MeV Proton Linac	927
	L. Groening, W.A. Barth, R. Berezov, G. Clemente, P. Forck, R. Hollinger, A. Krämer, C. Mühle, J. Pfister, G. Schreiber, J. Trüller, W. Vinzenz, C. Will GSI, Darmstadt, Germany N. Chauvin, O. Delferrière, O. Tuske CEA/IRFU, Gif-sur-Yvette, France B. Koubek, H. Podlech, U. Ratzinger, A. Schempp, R. Tiede IAP, Frankfurt am Main, Germany B. Launé, J. Lesrel IPN, Orsay, France C.S. Simon CEA/DSM/IRFU, France
	To provide the primary proton beam for the FAIR anti-proton research program, a 70 MeV, 70 mA linac is currently under design & construction at GSI. The nc machine comprises an ECR source, a 3 MeV RFQ, and a DTL based on CH-cavities. Up to 36 MeV pairs of rf-coupled cavities (CCH) are used. A prototype cavity has been built and is prepared for high power rf-testing. An overview of the status as well as on the perspectives of the project is given.
THPB035	Experience with a 4-Rod CW Radio Frequency Quadrupole	930
	P. Gerhard, W.A. Barth, L.A. Dahl, W. Hartmann, G. Schreiber, W. Vinzenz, H. Vormann GSI, Darmstadt, Germany
	Since 1991 the High Charge State Injector (HLI) provides heavy ion beams for the linear accelerator UNILAC at GSI*. It is equipped with an ECR ion source and an RFQ-IH linac which accelerates highly charged ion beams with high duty factor of up to 30% to 1.4 MeV/u for further acceleration in the Alvarez DTL of the UNILAC. Main user of these beams is the Super Heavy Element (SHE) research, one of the outstanding projects at GSI**. Experiments like TASCA and SHIP strongly benefit from the high average beam intensities. After two decades of successful operation the four-rod Radio Frequency Quadrupole (RFQ) accelerator was replaced in 2010 by a newly designed RFQ of the same type**. Besides higher beam transmission, the principal intention of this upgrade was to raise the duty factor up to 100%, since the HLI is foreseen as injector for the upcoming cw linac dedicated to the SHE program**. Commissioning and operational experience from the first years revealed that this goal could not be reached easily. In this paper we present the RFQ design, commissioning results, operational experience and future activities. * N. Angert et al., EPAC92, Berlin, Germany (1992), p. 167 ** L. Dahl et al., LINAC10, Tsukuba, Japan (2010), MOP042, and references therein
THPB036	The New Option for a Front End of Ion Linac	933
	A.D. Kovalenko JINR, Dubna, Moscow Region, Russia A. Kolomiets ITEP, Moscow, Russia
	The standard ion linac front-end consisting of RFQ, two tanks of accelerating IH-structures, MEBTs with matching and focusing elements is modified to achieve better performances. Special vane section that provides the same beam transformation as debuncher and quadrupole triplet is added within the RFQ tank, whereas superconducting focusing elements, solenoids, for example, are used between the IH - structure tanks. Test frond end was designed to provide the output beam energy up to 4 MeV/u for the particles with charge-to-mass ratio of 0.16 < q/m ≤ 1. Results of beam dynamics simulation are presented. Possible application of the considered scheme for the NICA facility at JINR (Dubna, Russia) is discussed.
THPB037	Iron Beam Acceleration with DPIS	936
	M. Okamura BNL, Upton, Long Island, New York, USA P.J. Jandovitz Cornell University, Ithaca, New York, USA T. Kanesue IAP, Frankfurt am Main, Germany M. Sekine RLNR, Tokyo, Japan T. Yamamoto RISE, Tokyo, Japan
	Funding: The work supported by US. DOE and RIKEN Japan. It has been proved that direct plasma Injection Scheme (DPIS) is an efficient way to accelerate high current highly charged state heavy ion beam. More than 50 mA (peak current) of various heavy ion beams can be easily accelerated. However, it was rather difficult to obtain longer pulse especially for highly charged particles. To induce highly charged states ions, a high plasma temperature is required at the laser irradiation point and the high temperature automatically gives a very fast expansion velocity of the plasma. This shortens the ion beam pulse length. To compensate the shorter ion pulse length, we can extend the plasma drift length, but it will dilute the brightness of the plasma since the plasma expands three dimensionally. To avoid the reduction of the brightness, a simple long solenoid was applied to confine the diverging angle of the plasma expansion. In the conference, this new technique will be explained and the latest results of iron beam acceleration will be shown.
THPB038	Assembly and RF Tuning of the Linac4 RFQ at CERN	939
	C. Rossi, A. Dallocchio, J. Hansen, J.-B. Lallement, A.M. Lombardi, S.J. Mathot, D. Pugnat, M.A. Timmins, G. Vandoni, M. Vretenar CERN, Geneva, Switzerland M. Desmons, A. France, Y. Le Noa, J. Novo, O. Piquet CEA/DSM/IRFU, France
	The fabrication of Linac4 is progressing at CERN with the goal of making a 160 MeV H− beam available to the LHC injection chain as from 2015. In the Linac4 the first stage of beam acceleration, after its extraction from the ion source, is provided by a Radiofrequency Quadrupole accelerator (RFQ), operating at the RF frequency of 352.2 MHz and which accelerates the ion beam to the energy of 3 MeV. The RFQ, made of three modules, one meter each, is of the four-vane kind, has been designed in the frame of a collaboration between CERN and CEA and has been completely machined and assembled at CERN. The paper describes the assembly of the RFQ structure and reports the results of RF low power measurements, in order to achieve the required accelerating field flatness within 1% of the nominal field profile.
THPB039	Design of a Four-Vane RFQ for China ADS Project	942
	Z.L. Zhang, X. Du, Y. He, X. Jin, C. Li, Y. Liu, A. Shi, L.P. Sun, B. Zhang, H.W. Zhao IMP, Lanzhou, People's Republic of China M.D. Hoff, A.R. Lambert, D. Li, J.W. Staples, S.P. Virostek LBNL, Berkeley, California, USA J. Wang Lanzhou University of Technology, People's Republic of China C. Zhang IAP, Frankfurt am Main, Germany
	A four-vane RFQ accelerator has been designed for the ADS project which has been launched in China since 2011. As one of the front ends of C-ADS LINAC, the RFQ works at a frequency of 162.5 MHz, accelerating the proton beam from 35 keV to 2.1 MeV. Due to the CW (continuous wave) operating mode, a small Kilpatric factor of 1.2 was adopted. At the same time, Pi-mode rods are employed to reduce the effect of dipole mode on quadrupole mode, and cavity tuning will be implemented by temperature adjustment of cooling water. Beam dynamics design, RF cavity design, thermal and stress analysis all will be presented in the paper.
THPB040	High-Power RF Conditioning of the TRASCO RFQ	945
	E. Fagotti, L. Antoniazzi, F. Grespan, A. Palmieri INFN/LNL, Legnaro (PD), Italy M. Desmons CEA/DSM/IRFU, France
	The TRASCO RFQ is designed to accelerate a 40 mA proton beam up to 5 MeV. It is a CW machine which has to show stable operation and provide the requested availability. It is composed of three electromagnetic segment coupled via two coupling cells. Each segment is divided into two 1.2 m long OFE copper modules. The RFQ is fed through eight loop-based power couplers to deliver RF to the cavity from a 352.2 MHZ, 1.3 MW klystron. After couplers conditioning, the first electromagnetic segment was successfully tested at full power. RFQ cavity reached the nominal 68 kV inter-vane voltage (1.8 Kilp.) in CW operation. Moreover, during conditioning in pulsed operation, it was possible to reach 83 kV inter-vane voltage (2.2 Kilp.) with a 1% duty cycle. The description of the experimental setup and procedure, as well as the main results of the conditioning procedure will be reported in this paper.
THPB042	Production and Quality Control of the First Modules of the IFMIF-EVEDA RFQ	948
	F. Scantamburlo, R. Dima, A. Pepato INFN- Sez. di Padova, Padova, Italy C. Roncolato INFN/LNL, Legnaro (PD), Italy
	The IFMIF/EVEDA RFQ, designed to accelerate a 125mA D+ beam from 0.1 MeV to 5 MeV at a frequency of 175 MHz, consists of 18 modules with length of ~550 mm each. The production of the modules has been started and 2 prototype modules plus module 16 have undergone all the production steps, including precision milling and brazing. The progress of the construction and especially the fine tuning of the design and engineering phase are reported.
THPB043	The RFQ injector for the Radioactive Ion Beam of SPES Project	951
	M. Comunian, F. Grespan, A. Palmieri, A. Pisent INFN/LNL, Legnaro (PD), Italy
	A Continous Wave Radio Frequency Quadrupole Accelerator has been designed for the Radioactive Ion Beam of SPES Project to be used as an Injector of the ALPI Linac. The RFQ frequency is 80 MHz for an input energy of 40 keV, with output energy of 5 MeV and ion ratio q/A<= 1/7. Particular care has been put in the design phase to include an internal bunching section able to reduce the longitudinal output emittance. The details of the RF study of such a cavity are included as well.
THPB044	Plans for an Integrated Front-End Test Stand at the Spallation Neutron Source	954
	M.S. Champion, A.V. Aleksandrov, M.T. Crofford, D. Heidenreich, Y.W. Kang, J. Moss, R.T. Roseberry, J.P. Schubert ORNL, Oak Ridge, Tennessee, USA
	Funding: Work performed at Oak Ridge National Laboratory, which is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. A spare Radio-Frequency Quadrupole (RFQ) is presently being fabricated by industry with delivery to Oak Ridge National Laboratory planned in late 2012. The establishment of a test stand at the Spallation Neutron Source site is underway so that complete acceptance testing can be performed during the winter of 2012-2013. This activity is the first step in the establishment of an integrated front-end test stand that will include an ion source, low-energy beam transport (LEBT), RFQ, medium-energy beam transport, diagnostics, and a beam dump. The test stand will be capable of delivering an H− ion beam of up to 50 mA with a pulse length of 1 ms and a repetition rate of 60 Hz or a proton beam of up to 50 mA, 100 μs, 1 Hz. The test stand will enable the following activities: complete ion source characterization; development of a magnetic LEBT chopper; development of a two-source layout; development of beam diagnostics; and study of beam dynamics of high intensity beam.
THPB046	RF Setup of the MedAustron RFQ	957
	B. Koubek, A. Schempp, J.S. Schmidt IAP, Frankfurt am Main, Germany J. Haeuser Kress GmbH, Biebergemuend, Germany
	A Radio Frequency Quadrupole (RFQ) was built for the injector of the cancer treatment facility MedAuston in Austria. For the RF design simulations were performed using CST Microwave Studio and the structure was manufactured by Firma Kress in Biebergemuend, Germany. The simulations and the RF setup of the delivered RFQ are presented in this paper.
THPB047	Test RFQ for the MAX Project	960
	M. Vossberg, H. Klein, H. Podlech, A. Schempp, C. Zhang IAP, Frankfurt am Main, Germany A. Bechtold NTG Neue Technologien GmbH & Co KG, Gelnhausen, Germany
	As a part of the MAX project it will be demonstrated by simulations and thermal measurements, that a 4-rod-RFQ is the right choice even at cw-operation. A 4-rod Test-RFQ with a resonance frequency of 175 MHz has been designed and built for the MAX-Project. But the RFQ had to be modified to solve the cooling problem at cw-operation, the geometrical precision had to be improved as well as the rf-contacts. The developments led to a new layout and a sophisticated production procedure of the stems and the electrodes. Calculations show an improved Rp-value leading to powerlosses of ca. 25 kW/m only, which is about half of the powerlosses which could be achieved safely at cw-operation of the similar Saraf-RFQ. Thermal measurements and simulations with the single components are in progress. The temperature distribution in cw-operation will be measured and the rf-performance checked.
THPB049	Tuning Studies on 4-Rod-RFQs	963
	J.S. Schmidt, B. Klump, B. Koubek, A. Schempp IAP, Frankfurt am Main, Germany
	A NI LabVIEW based Tuning Software has been devel- oped to structure the tuning process of 4-rod Radio Fre- quency Quadrupole s (RFQs). Its results are compared to measurement data of 4-rod RFQs in different frequency ranges. For the optimization of RFQ design parameters, a certain voltage distribution along the electrodes of an RFQ is assumed. Therefore an accurate tuning of the voltage distribution is very important for the beam dynamic prop- erties of an RFQ. A variation can lead to particle losses and reduced beam quality especially at higher frequencies. Our electrode design usually implies a constant longitudi- nal voltage distribution. For its adjustment tuning plates are used between the stems of the 4-rod-RFQ. These pre- dictions are based, in contrast to other simulations, on mea- surements to define the characteristics of the RFQ as it was build - not depending on assumptions of the design. This will lead to a totally new structured process of tuning 4- rod-RFQs in a broad range of frequencies by using the pre- dictions of a software. The results of these studies are pre- sented in this paper.
THPB050	RFQ With Improved Energy Gain	966
	A. Kolomiets ITEP, Moscow, Russia A.S. Plastun MEPhI, Moscow, Russia
	RFQ structure is practically only one choice for using in front ends of ion linacs for acceleration up to energy about 3 MeV. This limit is due to its relatively low acceleration efficiency. However it isn’t intrinsic feature of RFQ principle. It is defined only by vane geometry of conventional RFQ structure with sinusoidal modulation of vanes. The paper presents results of analysis RFQ with modified vane geometries that allow to improve acceleration efficiency. RFQ with modified vanes was used for design second section of heavy ion injector of TWAC for acceleration of ions with Z/A = 0.33 up to 7 MeV/u.
THPB051	Improvements at the BNL 200 MeV Linac	969
	D. Raparia, J.G. Alessi, B. Briscoe, J.M. Fite, O. Gould, V. LoDestro, M. Okamura, J. Ritter, A. Zelenski BNL, Upton, Long Island, New York, USA
	After reconfiguration of the low energy (35 keV) and the medium energy (750 keV) transport lines in 2009-10, the Brookhaven linac delivered the highest intensity beam since it was built in 1970 (~120 μA average current of H− to the Brookhaven Linac Isotope Producer). It also delivered lower emittance polarized H− ion beam for the polarized program at RHIC. To increase the intensity further, the match into the RFQ was improved by reducing the distance from the fnal focusing solenoid to the RFQ and replacing the buncher in the 750 keV line with one with higher Q value, to allow operation at higher power. We also found that drift –tube linac tank number 7 was operating with about 1 MW lower power than design. The transmission efficiencies and beam quality will be discussed in the paper.
THPB052	Recent Progress with the J-PARC RFQs	972
	Y. Kondo, K. Hasegawa, T. Morishita JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan H. Kawamata, F. Naito, T. Sugimura KEK, Ibaraki, Japan
	In this paper, we will report recent topics about J-PARC RFQs. First, the operating RFQ (RFQ I) have been recovered from the long shutdown due to the earthquake. This RFQ have been suffered from breakdown problem since 2008, therefore we have been developing a back-up RFQ (RFQ II). In April 2012, the high power test was successfully performed. Finally, we are fabricating a new RFQ for the beam-current upgrade of the J-PARC linac (RFQ III). The status of these RFQs are described.
THPB055	Numerical Simulations of ProjectX/PXIE RFQ	975
	J.-F. Ostiguy, A. Saini, N. Solyak Fermilab, Batavia, USA
	Funding: Fermi Research Alliance, LLC under DOE Contract No. De-AC02-07CH11359 Project-X is a proposed superconducting linac-based high intensity proton source at Fermilab. The machine first stages operate in CW mode from 2.1 to 3 GeV and a high bandwidth chopper is used to produce the required bunch patterns. A 162.5 MHz CW RFQ accelerates the beam from 30 keV to 2.1 MeV. A concern with CW operation is that losses either within the RFQ or in the dowstream modules should be well-understood and remain very low to ensure safe and/or reliable operation. In this contribution, we investigate the suitability of existing RFQ codes and model the PXIE RFQ (ProjectX test facility) designed constructed by LBNL to make useful predictions of loss patterns and phase space distribution.
THPB061	Experimental and Simulation Study of the Long-path-length Dynamics of a Space-charge-dominated Bunch	978
	I. Haber, B.L. Beaudoin, S. Bernal, R.A. Kishek, T.W. Koeth, Y. Mo UMD, College Park, Maryland, USA
	Funding: Work supported by the United States Department of Energy and the Office of Naval Research. The University of Maryland Electron Ring (UMER) is a low-energy (10 keV) electron facility built to study, on a scaled machine, the long-propagation-length evolution of a space-charge-dominated beam. Though constructed in a ring geometry to achieve a long path length at modest cost, UMER has observed important space-charge physics directly relevant to linear machines. Examples will be presented that emphasize studies of the longitudinal dynamics and comparisons to axisymmetric simulations. The detailed agreement obtained between simulation and experiment will be presented as evidence that the longitudinal physics observed is not strongly influenced by the ring geometry. Novel phenomena such as soliton formation, unimpeded bunch-end interpenetration, and an instability that occurs after this interpenetration, will be discussed.
THPB062	Multipole Field Effects for the Superconducting Parallel-Bar/RF-Dipole Deflecting/Crabbing Cavities	981
	S.U. De Silva, J.R. Delayen ODU, Norfolk, Virginia, USA S.U. De Silva JLAB, Newport News, Virginia, USA
	The superconducting parallel-bar deflecting/crabbing cavity is currently being considered as one of the design options in rf separation for the Jefferson Lab 12 GeV upgrade and for the crabbing cavity for the proposed LHC luminosity upgrade. Knowledge of multipole field effects is important for accurate beam dynamics study of rf structures. The multipole components can be accurately determined numerically using the electromagnetic surface field data in the rf structure. This paper discusses the detailed analysis of those components for the fundamental deflecting/crabbing mode and higher order modes in the parallel-bar deflecting/crabbing cavity.
THPB063	Simulated Performance of the CARIBU EBIS Charge Breeder Transport Line	984
	C. Dickerson, S.A. Kondrashev, B. Mustapha, P.N. Ostroumov ANL, Argonne, USA
	Funding: This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract number DE-AC02-06CH11357. An Electron Beam Ion Source (EBIS) has been designed and is being built to charge breed ions from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) for post acceleration in the Argonne Tandem Linear Accelerator System (ATLAS). The calculated transverse acceptance of the EBIS charge breeder can approach the emittance of the injected ion beam, so beam distortion during transport could lead to incomplete injection and a decrease in the overall system efficiency. The beam quality can be maintained for simulations of the transport line using the ideal ion beam parameters. This paper reports the results of the electrostatic and ion beam transport simulations used to minimize the ion beam distortions by optimizing component designs and configurations.
THPB064	Beam Dynamics Tools for Linacs Design	987
	A.S. Setty THALES, Colombes, France
	In the last 25 years, we have been using our in house 3D code PRODYN * for electron beam simulations. We have also been using our in house code SECTION for the design of the travelling wave accelerating structures and the beam loading compensation. PRODYN follows in time, the most complicated electron trajectories with relativistic space-charge effects. This code includes backward as well as forwards movements. This paper will describe those two codes and will give some simulations and measurements results. * D. Tronc and A. Setty, Electrons RF auto-focusing and capture in bunchers, Linear Accelerator Conference 1988, Virginia.
THPB065	Status of the Beam Dynamics Code DYNAC	990
	E. Tanke, J.A. Rodriguez, W. Wittmer, X. Wu FRIB, East Lansing, Michigan, USA S. Valero CEA, Gif-sur-Yvette, France D. Wang NSCL, East Lansing, Michigan, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The beam dynamics code DYNAC* was originally developed at CERN. For accelerating elements a set of very accurate quasi-Liouvillian beam dynamics equations was introduced, applicable to protons, heavy ions and non-relativistic electrons. Furthermore, DYNAC contains three space charge routines, including a 3D version**. More recently, a numerical method has been added, capable of simulating a multi charge state ion beam in accelerating elements (i.e. cavities). Beam line devices such as sextupoles and quadrupole-sextupole magnets as well as electrostatic devices are now also included. Capability of second order calculations of such elements for a multi charge state beam has been implemented. Benchmarking of the code, in particular for a multi-charge state beam is discussed. Comparison of beam simulations results with beam measurements on the MSU ReAccelerator (ReA) are reported. The possibility of using DYNAC as an online tool for ReA and FRIB is discussed. *DYNAC: A Multi-Particle Beam Dynamics Code for Leptons and Hadrons, E.Tanke et al,LINAC2002 **HERSC: A New 3 Dimensional Space Charge Routine for High Intensity Bunched Beams, E.Tanke et al,LINAC2002
THPB066	Photoinjector SRF Cavity Development for BERLinPro	993
	A. Neumann, W. Anders, T. Kamps, J. Knobloch HZB, Berlin, Germany E.N. Zaplatin FZJ, Jülich, Germany
	In 2010 HZB has received approval to build BERLinPro, an ERL project to demonstrate energy recovery at 100 mA beam current by pertaining a high quality beam. These goals place stringent requirements on the SRF cavity for the photoinjector which has to deliver a small emittance 100 mA beam with at least 1.5 MeV kinetic energy while limited by fundamental power coupler performance to about 200 kW forward power. In oder to achieve these goals the injector cavity is being developed in a three stage approach. The current design studies focus on implementing a normal conducting cathode insert into a newly developed superconducting photoinjector cavity. In this paper the fundamental RF design calculations concerning cell shape for optimized beam dynamics as well as SRF performance will be presented. Further studies concentrate on the HZDR based choke cell design to implement the high quantum efficiency normal conducting cathode with the SRF cavity.
THPB068	First Observation of Photoemission Enhancement from Copper Cathode Illuminated by Z-Polarized Laser Pulse	996
	H. Tomizawa, H. Dewa, A. Mizuno, T. Taniuchi JASRI/SPring-8, Hyogo, Japan
	Since 2006, we have developed a novel photocathode gun gated by laser-induced Schottky-effect. This new type of gun utilizes a laser’s coherency to aim at a compact femtosecond laser oscillator as an IR laser source using Z-polarization on the photocathode. This Z-polarization scheme reduces the laser photon energy (making it possible to excite the cathode with a longer wavelength) by reducing the work function of cathode due to Schottky effect. A hollow laser incidence is applied with a hollow convex lens in a vacuum that is focused after passing the laser beam through a radial polarizer. According to our calculations (convex lens: NA=0.15), a Z-field of 1 GV/m needs 1.26 MW at peak power for the fundamental wavelength (792 nm). In the first demonstration of Z-field emission, enhancement was done with a copper cathode at THG (264 nm). Consequently, we observed 1.4 times enhancement of photoemission at 1.6 GV/m of an averaged laser Z-field on the cathode surface. We report the first observation and analysis of the emission enhancements with this laser-induced Schottky-effect on metal copper photocathodes by comparing radial and azimuthal polarizations of the incident laser pulses.
THPB069	Beam Dynamics Studies for SRF Photoinjectors	999
	T. Kamps, A. Neumann, J. Völker HZB, Berlin, Germany
	The SRF photoinjector combines the advantages of photo-assisted production of high brightness, short electron pulses and high gradient, low-loss continuous wave (CW) operation of a superconducting radiofrequency (SRF) cavity. The paper discusses beam dynamics considerations for FEL and ERL class applications of SRF photoinjectors. One case of particular interest is the design of the SRF photoinjector for BERLinPro, an ERL test facility demanding a high brightness beam with an emittance better than 1 mm mrad at 77 pC and average current of 100 mA.
THPB073	Initial RF Tests of the Diamond S-Band Photocathode Gun	1002
	C. Christou, S.A. Pande Diamond, Oxfordshire, United Kingdom
	An S-band photocathode electron gun designed to operate at repetition rates up to 1 kHz CW has been designed at Diamond and manufactured at FMB*. The first test results of this gun are presented. Low-power RF measurements have been carried out to verify the RF design of the gun, and high-power conditioning and RF test has begun. Initial high power tests have been carried out at 5 Hz repetition rate using the S-band RF plant normally used to power the Diamond linac: the benefits and limitations of this approach are considered, together with plans for further testing. * J. H. Han et al, NIM A 647(2011) 17-24
THPB074	RF Photoinjector and Radiating Structure for High-power THz Radiation Source	1005
	S.M. Polozov, T.V. Bondarenko MEPhI, Moscow, Russia Y.A. Bashmakov LPI, Moscow, Russia
	Sources of high-power electromagnetic radiation in THz band are becoming promising as a new method of a low activation introscopy. Research and development of accelerating RF photoinjector and radiating system for THz radiation source are reported. The photoinjector is based on disk loaded waveguide (DLW). Two different designs of accelerating structures were modeled: widespread 1.6 cell of DLW structure and travelling wave resonator structure. The resonant models of these structures and the structures with power ports were designed. Electrodynamics characteristics and electric field distribution for all models were acquired. Results of picoseconds photoelectron beam dynamics in modeled structures are reported. Design of decelerating structures exciting Cherenkov radiation are based on corrugated metal channel and metal channel coated with dielectric. Analysis of radiation intensity and frequency band are presented.
THPB076	Design Issues of the Proton Source for the ESS Facility	1008
	L. Celona, L. Allegra, C. Caliri, G. Castro, G. Ciavola, R. Di Giugno, S. Gammino, D. Mascali, L. Neri INFN/LNS, Catania, Italy
	The European Spallation Source facility will be one of the fundamental instruments for science and engineering of the future. A 2.5 GeV proton accelerator is to be built for the neutron production. INFN-LNS is involved in the Design Update for the proton source and Low Energy Beam Transport (LEBT) line. The proton source is required to produce a low emittance 90 mA beam, 2.86 ms pulsed with a repetition rate of 14 Hz. Microwave Discharge Ion Sources (MDIS) enable us to produce such high intensity proton beams characterized by very low emittance (< 0.2 π.mm.mrad). The source design is based on a flexible magnetic system which can be adapted to electrostatic Bernstein waves heating mechanism; this will permit a strong increase in the electron density with an expected boost of the output current. The main features of the source design, including the microwave injection system and beam extraction, will be described hereinafter.
THPB079	Development of a Superconducting Focusing Solenoid for CADS	1011
	W. Wu, S.F. Han, Y. He, L.Z. Ma, D.S. Ni, Z.J. Wang, B.M. Wu, W.J. Yang, X.L. Yang, S.J. Zheng, L. Zhu IMP, Lanzhou, People's Republic of China
	A superconducting focusing solenoid has been designed and developed for the China Accelerator Driven System (CADS). In order to meet the requirement of focusing strength and fringe field while minimizing physical size of the solenoid, the novel optimizing design method based on linear programming method was employed. In this report, we will introduce the design of the solenoid including magnetic field optimization, mechanical design and quench protection. The fabrication and the test results of the solenoid will also be introduced in this report.
THPB081	The Development of Timing Control System for RFQ	1014
	J.N. Bai, S. Xiao, T.G. Xu, L. Zeng IHEP, Beijing, People's Republic of China
	Timing control system based on VME configuration is developed to meet the need of 3.5 MeV RFQ. An EPICS driver is provided to control its work. The timing control system satisfies request after examination. In the future, it will be used in the machine running. This paper introduces the Timing control hardware, VME interface, EPICS driver for Timing control system and MEDM operator interface.
THPB083	Status of E-XFEL String and Cryomodule Assembly at CEA-Saclay	1017
	C. Madec CEA, Gif-sur-Yvette, France S. Berry, J.-P. Charrier, A. Daël, M. Fontaine, Y. Gasser, O. Napoly, Y. Sauce, C.S. Simon, T.V. Vacher, B. Visentin CEA/DSM/IRFU, France A. Brasseur, P. Charon, C. Cloué, S. Langlois, G. Monnereau, J.L. Perrin, D. Roudier, N. Sacépé CEA/IRFU, Gif-sur-Yvette, France
	As In-Kind contributor to E-XFEL project, CEA is committed to the integration on the Saclay site of the 100 cryomodules of the superconducting linac as well as to the procurement of the magnetic shieldings, superinsulation blankets and 31 cold beam position monitors of the re-entrant type. The assembly infrastructure has been renovated from the previous Saturne Synchrotron Laboratory facility: it includes a 200 m2 clean room complex with 120 m2 under ISO4, 1325 m2 of assembly platforms and 400 m2 of storage area. In parallel, CEA has conducted industrial studies and three cryomodule assembly prototyping both aiming at preparing the industrial file, the quality management system and the commissioning of the assembly plant, tooling and control equipments. In 2012, the contract of the integration will be placed to a subcontractor. The paper will summarize the outputs of the preparation and prototyping phases and the up-coming industrial phase.
	Slides THPB083 [1.868 MB]
THPB084	A Low-Level RF Control System for a Quarter-Wave Resonator	1020
	J.-W. Kim, D.G. Kim IBS, Daejeon, Republic of Korea C.K. Hwang KAERI, Daejon, Republic of Korea
	A low-level rf control system was designed and built for an rf deflector, which is a quarter wave resonator and was designed to deflect a secondary electron beam to measure the bunch length of an ion beam. The deflector has a resonance frequency at near 88 MHz, and its required phase stability is approximately ±1° and amplitude stability less than ±1%. The control system consists of analog input and output components, and a digital system based on an FPGA for signal processing. It is a cost effective system, while meeting the stability requirements. Some basic properties of the control system were measured. Then the capability of the rf control has been tested using a mechanical vibrator made of a dielectric rod attached to an audio speaker system, which can induce regulated perturbation in the electric fields of the resonator. The control system is flexible such that its parameters can be easily configured to compensate for disturbance induced in the resonator.
THPB085	LLRF Automation for the 9mA ILC Tests at FLASH	1023
	J. Branlard, V. Ayvazyan, O. Hensler, H. Schlarb, Ch. Schmidt, N.J. Walker, M. Walla DESY, Hamburg, Germany G.I. Cancelo, B. Chase Fermilab, Batavia, USA J. Carwardine ANL, Argonne, USA W. Cichalewski, W. Jałmużna TUL-DMCS, Łódź, Poland S. Michizono KEK, Ibaraki, Japan
	Since 2009 and under the scope of the International Linear Collider (ILC) R&D, a series of studies takes place twice a year at the Free electron Laser accelerator in Hamburg, (FLASH) DESY, in order to investigate technical challenges related to the high-gradient, high-beam-current design of the ILC. Such issues as operating cavities near their quench limit with high beam loading or in klystron saturation regime are investigated, always pushing the limits of FLASH nominal operational conditions. To support these studies, a series of automation algorithms have been developed and implemented at DESY. These include automatic detection of cavity quenches, automatic adjustment of the superconducting cavity quality factor, and automatic compensation of detuning due to Lorentz forces. This paper explains the functionality of these automation tools, details about their implementation, and shows the experience acquired during the last 9mA ILC test which took place at DESY in February 2012. The benefit of these algorithms and the R&D results these automation tools have permitted will be clearly explained.
THPB086	Precision Regulation of RF Fields with MIMO Controllers and Cavity-based Notch Filters	1026
	Ch. Schmidt, J. Branlard, S. Pfeiffer, H. Schlarb DESY, Hamburg, Germany W. Jałmużna TUL-DMCS, Łódź, Poland
	The European XFEL requires a high precision control of the electron beam, generating a specific pulsed laser light demanded by user experiments. The low level radio frequency (LLRF) control system is certainly one of the key players for the regulation of accelerating RF fields. A uTCA standard LLRF system was developed and is currently under test at DESY. Its first experimental results showed the system performance capabilities. Investigation of regulation limiting factors evidenced the need for control over fundamental cavity modes, which is done using complex controller structures and filter techniques. The improvement in measurement accuracy and detection bandwidth increased the regulation performance and contributed to integration of further control subsystems.
THPB089	Magnetic Characterization of the Phase Shifter Prototypes Built by CIEMAT for E-XFEL	1029
	I. Moya, J. Calero, J.M. Cela-Ruiz, L. García-Tabarés, A. Guirao, J.L. Gutiérrez, L.M. Martinez, T. Martínez de Alvaro, E. Molina Marinas, L. Sanchez, S. Sanz, F. Toral, C. Vázquez, J.G.S. de la Gama CIEMAT, Madrid, Spain J. Campmany, J. Marcos, V. Massana CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	Funding: Work partially supported by Spanish Ministry of Science and Innovation under SEI Resolution on 17-September-2009 and project ref. AIC-2010-A-000524 The European X-ray Free Electron Laser (E-XFEL) will be based on a 10 to 17.5 GeV electron linac that will be used in the undulator system to obtain ultra-brilliant X-ray flashes from 0.1 to 6 nanometres for experimentation. The undulator system is formed by undulators and intersections between them, where a quadrupole on top of a precision mover, a beam position monitor, two air coils and a phase shifter are allocated. The function of the phase shifter is to adjust the phase of the electron beam and the radiation when they enter in an undulator according to the different beam energies and wavelengths. CIEMAT is working on the development of the phase shifters, as part of the Spanish in-kind contribution to the E-XFEL project. Several problems reported elsewhere were detected in the first prototype, which did not fulfil the first field integral specification. This paper describes the magnetic measurements realized on the second and third prototypes in the test bench at CELLS, together with the tuning process to decrease the field integral dependence with gap.
THPB091	Machine Protection Issues and Solutions for Linear Accelerator Complexes	1032
	M. Jonker, H. Schmickler, R. Schmidt, D. Schulte CERN, Geneva, Switzerland M.C. Ross SLAC, Menlo Park, California, USA
	The workshop “Machine Protection focusing on Linear Accelerator Complexes” was held from 6-8 June 2012 at Cern. This workshop brought together experts working on machine protection systems for accelerator facilities with high brilliance or large stored beam energies, with the main focus on linear accelerators and their injectors. An overview of the machine protection systems for several accelerators was given. Beam loss mechanisms and their detection were discussed. Mitigation of failures and protection systems were presented. This paper summarises the workshop and reviews the current state of the art in machine protection systems.
THPB092	Recent Improvements in SPring-8 Linac for Early Recovery from Beam Interruption	1035
	S. Suzuki, T. Asaka, H. Dewa, H. Hanaki, T. Kobayashi, T. Magome, A. Mizuno, T. Taniuchi, H. Tomizawa, K. Yanagida JASRI/SPring-8, Hyogo-ken, Japan
	The 1GeV SPring-8 linac is an injector for the SPring-8 synchrotron radiation storage ring with 8GeV booster synchrotron. In recent years, backup systems were installed to eliminate long-time interruption of the beam injections: The main gun system is usually operated, and the second gun is always pre-heated and can inject electron beams into a buncher section with an interval of several minutes in case the main gun failed. The first klystron, that feeds RF powers to the buncher system and the downstream klystrons, can be relieved by the next klystron with an interval of about 20 minutes by switching the waveguide circuit. When one of the eleven working klystrons faults, one of standby klystrons, which are kept for hot spares on line, is automatically activated to accelerate beams instead of the failed one without beam interruption. The total downtime in FY2012 was 0.12% in top-up operation user time. The averaged fault frequency was 0.2 times per day.
THPB094	Performance of Beam Chopper at SARAF via RF Deflector Before the RFQ	1038
	A. Shor, D. Berkovits, I. Fishman, A. Grin, B. Kaizer, L. Weissman Soreq NRC, Yavne, Israel
	We describe performance of a beam chopper at the SARAF accelerator consisting of an HV deflector preceding the RFQ. The deflector and electronics, developed at LNS Catania, was designed to provide slow beam chopping for beam testing and diagnostics where low beam power is necessary. The HV deflector sweeps away the low energy beam onto a water cooled beam catcher, while a fast HV switch momentarily switches off the HV whenever a transmitted beam to the RFQ is desired. We report on measurements with this chopping system, where minimum transmitted beam pulse of 180 ns duration is attained with a rise and fall time of several nano-seconds. We performed beam dynamics simulations of SARAF Phase-I, including the deflector, where the short rise and fall times of the chopped beam is attributed to the tight collimation of the deflected beam provided by the RFQ and the fast Faraday Cup. We also describe beam dynamics simulations which suggest that single RFQ bunch selection can be achieved with the existing chopping system, during zero-crossover for positive-negative deflecting HV waveform.
THPB095	Designing of a Phase-mask-type Laser Driven Dielectric Accelerator for Radiobiology	1041
	K. Koyama UTNL, Ibaraki, Japan A. Aimidura, M. Uesaka The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan Y. Matsumura University of Tokyo, Tokyo, Japan T. Natsui, M. Yoshida KEK, Ibaraki, Japan
	Funding: This work is supported by KAKENHI, Grant-in-Aid for Scientific Research (C) 24510120 In order to estimate the health risk of a low radiation dose, basic processes of the radiobiology should be clarified by shooting a DNA using a spatially and temporary defined particle beam or X-ray. A suitable beam size is as small as a resolving power of an optical microscope of a few hundred nanometers. Photonic crystal accelerators (PCA) are capable of delivering nm-beams of sub-fs pulses because the characteristic length and frequency of PCAs are on the order of the laser light. Since the phase-mask type accelerator has a simpler structure than other types of PCAs, we are designing a phase-mask type laser driven dielectric accelerator. By adopting an unbalanced length of pillar and ditch (grating) of 4:1, a standing wave like acceleration field is produced in a acceleration channel. A pillar height and initial speed of injected electron are determined by analytically. The maximum acceleration gradient of 2 GeV/m is estimated. The required laser power is roughly estimated to be 6.5 GW. The simulation using CST-code also shows similar values to accelerate electrons by the phase-mask type accelerator.
THPB096	High-power Sources of RF Radiation Driven by Periodic Laser Pulses	1044
	S.V. Kuzikov, A.V. Savilov IAP/RAS, Nizhny Novgorod, Russia S.V. Kuzikov Omega-P, Inc., New Haven, USA
	Funding: Supported in part by DoE USA. A fast, periodic modulation of electron RF sources can be carried out in a form of Q-factor switching by means of fast RF switches, or in a form of I-switching by means of the bunched electron beam. If modulation frequency equals to time which is necessary for RF radiation to travel along the cavity and to come back, the RF oscillator can produce periodic, giant, short pulses which are desirable for many applications in order to avoid a breakdown. The produced RF pulses are phase and frequency locked by modulation shape. The mentioned effects of the phase and frequency locking remain also possible for RF sources operated in a single-mode regime. In last case the modulation frequency should be close to natural single-mode oscillation frequency. For example, one might control operation of a BWO by means of a small periodical modulation of the electron voltage in a drift section in-between a cathode and the corrugated interaction section. The necessary voltage modulation can be provided by means of a DC generator those voltage due to a photoconductivity is externally modulated with definite frequency by laser which irradiates GaAs isolator inserted in-between the electrodes.
THPB097	FRIB Front End Design Status	1047
	E. Pozdeyev, N.K. Bultman, G. Machicoane, G. Morgan, X. Rao, Q. Zhao FRIB, East Lansing, Michigan, USA V.L. Smirnov, S.B. Vorozhtsov JINR, Dubna, Moscow Region, Russia J. Stovall CERN, Geneva, Switzerland L.T. Sun IMP, Lanzhou, People's Republic of China L.M. Young LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The Facility for Rare Isotope Beams (FRIB) will provide a wide range of primary ion beams for nuclear physics research with rare isotope beams. The FRIB SRF linac will be capable of accelerating medium and heavy ion beams to energies beyond 200 MeV/u with a power of 400 kW on the fragmentation target. This paper presents the status of the FRIB Front End designed to produce uranium and other medium and heavy mass ion beams at world-record intensities. The paper describes the FRIB high performance superconducting ECR ion source, the beam transport designed to transport two-charge state ion beams and prepare them for the injection in to the SRF linac, and the design of a 4-vane 80.5 MHz RFQ. The paper also describes the integration of the front end with other accelerator and experimental systems.