TUPP —  Poster Session   (02-Sep-14   16:00—18:00)
Chair: S. Ramberger, CERN, Geneva, Switzerland
Paper Title Page
TUPP001 Cryogenic Performance of a New 72 MHz Quarter-Wave Resonator Cryomodule 437
 
  • Z.A. Conway, G.L. Cherry, R.L. Fischer, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.H. Kim, S.W.T. MacDonald, R.C. Murphy, P.N. Ostroumov, C.E. Peters, M.A. Power, T. Reid, J.R. Specht
    ANL, Argonne, Illinois, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under contract number DE-AC02-06CH11357.
The Argonne National Laboratory ATLAS accelerator’s Intensity and Efficiency Upgrade project has been successfully finished [1]. This upgrade substantially increases beam currents for experimenters working with the existing stable and in-flight rare isotope beams and for the neutron rich beams from the Californium Rare Isotope Breeder upgrade. A major portion of this project involved the replacement of three existing cryomodules, containing 18 superconducting (SC) accelerator cavities and 9 superconducting solenoids, with a single cryomodule containing 7 SC 72.75 MHz accelerator cavities optimized for ion velocities of 7.7% the speed of light and 4 SC solenoids all operating at 4.5 K. This paper reports the measured thermal load to the 4 K and 80 K coolant streams and compares these results to the pre-upgrade cryogenic system. 		 
 
TUPP002 Commissioning of the 72 MHz Quarter-Wave Cavity Cryomodule at ATLAS 440
 
  • M.P. Kelly, Z.A. Conway, S.M. Gerbick, M. Hendricks, M. Kedzie, S.H. Kim, S.W.T. MacDonald, R.C. Murphy, P.N. Ostroumov, T. Reid, S.I. Sharamentov, G.P. Zinkann
    ANL, Argonne, Illinois, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under contract number DE-AC02-06CH11357.
A cryomodule of seven 72 MHz SC quarter-wave cavities optimized for ions with v/c=0.077 has been commissioned in the ATLAS heavy-ion accelerator at Argonne. ATLAS has a new capability for increased beam currents with low beam losses for nuclear physics experiments using stable or rare isotope beams or neutron rich beams from the Californium Rare Isotope Breeder. The main goal for the cryomodule, to provide an accelerating voltage of 17.5 MV (2.5 MV/cavity), with no detectable beam losses has been met within the first month of commissioning. Thus far, cavities and primary subsystems including high-power couplers and pneumatic tuners are operating as designed with full availability. For present levels there is practically no field emission (EPEAK=40 MV/m) and RF losses of ~5 Watts/cavity are only half of that planned. Cavity fields will continue to be gradually increased, with the limits due to cavity quench measured at VACC=3.75 MV. Due to a combination of rf design and cavity processing, effective voltages are now 2 ½ times those for any other operational cavities for this v/c. We report here on the recent online test results and technical features of the present design. 		 
 
TUPP003 4 K Alignment of Superconducting Quarter-Wave Cavities and 9 T Solenoids in the ATLAS Intensity Upgrade Cryomodule 443
TUPOL02   use link to see paper's listing under its alternate paper code  
 
  • S.H. Kim, Z.A. Conway, W.G. Jansma, M. Kedzie, M.P. Kelly, P.N. Ostroumov
    ANL, Argonne, Illinois, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under contract number DE-AC02-06CH11357.
The superconducting cavities and, especially, the magnets in high intensity ion linacs need to be aligned to the beam with typical transverse tolerances of 0.25 mm and 0.1 degrees at temperatures of 1.8 – 4.5 K. This is necessary to limit the emittance growth and minimize the beam losses. A new cryomodule with 7 superconducting quarter-wave resonators and 4 superconducting solenoids has been installed and is now operated at the Argonne Tandem Linear Accelerator System (ATLAS). We developed the techniques necessary to assemble the superconducting components in this cryomodule at room temperature so that they are aligned to the beam axis at 4.5 K. We achieved transverse alignment tolerances of <0.2 mm RMS. In this paper, we will present the details of the alignment hardware, procedures and results. 		 
slides icon Slides TUPP003 [0.834 MB]  
 
TUPP004 An In-flight Radioactive Ion Separator Design for the ATLAS Facility 446
 
  • B. Mustapha, B. Back, C.R. Hoffman, B.P. Kay, J.A. Nolen, P.N. Ostroumov
    ANL, Argonne, USA
  
  Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
An in-flight radioactive beam separator, named AIRIS, is being designed to enhance the radioactive beam capabilities of the ATLAS facility at Argonne. In order to serve all the experimental areas while maintaining the stable beam capabilities, the separator design is of broadband type. This design allows the selected radioactive beam to come back on the ATLAS beam line while stable beams continue on the same straight line with the separator turned off. The separation is performed in two steps, the first is magnetic in a chicane made of four magnets and four multipoles, while the second uses an rf sweeper taking advantage of the time separation between the beam of interest and potential contaminants including the primary beam tail. We will report on the progress of the AIRIS design effort with special emphasis on the performance of the rf sweeper. 		 
 
TUPP005 Completion of Efficiency and Intensity Upgrade of the ATLAS Facility 449
TUPOL03   use link to see paper's listing under its alternate paper code  
 
  • P.N. Ostroumov, Z.A. Conway, C. Dickerson, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.H. Kim, Y. Luo, S.W.T. MacDonald, R.C. Murphy, B. Mustapha, R.C. Pardo, T. Reid, S.I. Sharamentov, K.W. Shepard, J.R. Specht, G.P. Zinkann
    ANL, Argonne, USA
  • A. Perry
    Illinois Institute of Technology, Chicago, Illlinois, USA
  
  Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
The ANL Physics Division has completed a major upgrade of the ATLAS National User Facility by successfully installing a new RFQ and cryomodule. The new normal conducting CW RFQ capable of providing 295 keV/u beams of any ion with m/q ≤7 from protons to uranium was fully integrated into ATLAS and has been in routine operation for more than a year. The RFQ doubled the efficiency of beam delivery to targets and opened the possibility to accelerate much higher intensity beams. Recently, the new cryomodule containing 7 high-performance 72.75 MHz superconducting quarter-wave resonators and 4 superconducting solenoids was successfully commissioned with beam. New design and fabrication techniques for these resonators resulted in record high voltages which were achieved during the beam commissioning. The new cryomodule provides 17.5 MV accelerating voltage which will be gradually raised by increasing the input RF power and improving LLRF system. The new cryomodule, which replaced 3 old cryomodules that used split-ring cavities, is also essential for high intensity stable beams. Results of beam commissioning and operation of ATLAS with the new RFQ and cryomodule will be presented. 		 
 
TUPP006 Design of Relativistic Magnetron for High Power Microwave Generation 452
 
  • R. Chandra, S.R. Ghodke, A.S. Patel, A. Sharma, S.K. Singh
    BARC, Mumbai, India
  
  A Linear Induction Accelerator based upon magnetic storage, utilising magnetic switches has been made and it is capable of providing a 400 kV diode voltage, 4 kA beam current for 100 ns pulse duration with 100 Hz repetition rate. It operates in a very high repetition rate due to the use of magnetic switches in it. The lesser shot to shot variation make this system ideal for a Relativistic Magnetron operation, where a huge dependence of output power on applied voltage and applied current is observed. A relativistic magnetron with axial extraction is analytically designed and simulated for this system. This relativistic magnetron is expected to give a power of 100 MW per pulse when operated in its full rating. The design features of this relativistic magnetron are presented here. This magnetron was designed for an output microwave frequency of 2.52 GHz.
*J. Benford, ''Space Applications of High-Power Microwaves'', IEEE Trans. Plasma Sci., vol. 36, no. 3, pp. 569–581, Jun. 2008 		 
 
TUPP007 Multi Gigawatt High Current Pulsed Electron Accelerator Technology Development Program at BARC 456
 
  • A. Sharma, R. Agarwal, M. Beg, R. Chandra, H. Choudhary, L.M. Gantayet, S.R. Ghodke, TS. Kolge, R. Kumar, S. Mitra, K.C. Mittal, A.S. Patel, A. Roy, P.C. Saroj, K. Senthil, V.K. Sharma, S.K. Singh
    BARC, Mumbai, India
  
  High current intense electron beams were investigated earlier for Flash X-rays and nuclear electromagnetic pulse generation. Starting with moderate parameters of 200 kV, 6 kA, 60 ns pulsed electron beam source from a system named Kilo Ampere Linear Injector (KALI-75) our latest development is KALI-30 GW system rated for 1 MV, 30 kA, 80 ns. First repetitive pulse LINAC without spark gap switching was developed as Linear Induction Accelerator (LIA-200) for technology demonstrations at 100 Hz. Also a repetitive Marx generator coupled reflex triode system to operate at 10 Hz. Next to this series of development LIA-400 has been developed to a capacity of 400 kV, 4 kA, 100 ns, 300 Hz. To make these pulse power systems applicable for big LINAC projects like nToF studies or ADS program, a high current electron gun has also been developed to give 100 A, 2 ns,10 Hz pulses.
References
[1].Amitava Roy et al, Journal of App. Physics 103, 2008.
[2].D. D. P. Kumar, et al. Rev. Sci. Inst., vol. 78, no. 11, 2007.
[3].Archana Sharma, et al., IEEE-PS Vol. 39, No. 5, 2011. 		 
 
TUPP009 Operation and Improvements of the ALBA Linac 459
 
  • R. Muñoz Horta, J.M. Gómez Cordero, F. Pérez
    CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
  
  The ALBA Light Source pre-injector is a 100 MeV electron Linac which started operation in July 2010. Since then, several improvements have been made to the Linac system to enhance the beam stability and the operation reliability with special focus to top-up mode operation requirements. A description of the modifications applied to the RF system and an overview of the different modes of injection are presented. Also operational experience in decay mode and in the recently implemented top-up mode are reported.  
 
TUPP013
 Sawtooth-wave prebuncher with two gaps in SSC-LIANC  
SUPG005   use link to see paper's listing under its alternate paper code  
 
  • X.H. Zhang
    IMP, Lanzhou, People's Republic of China
  
  A new heavy ion linac is under construction in HIRFL (Heavy Ion Research Facility in Lanzhou), which replaces the present SFC (Sector Focusing Cyclotron) cyclotron as the injector of SSC (Separated Sector Cyclotron).  
 
TUPP014
 A New-concept Injector for Heavy Ion Synchrotrons  
 
  • H. Zhao, Q. Jin, L. Lu, L.T. Sun, L.P. Sun, J. Zhang, X.Z. Zhang, Z.L. Zhang, H.W. Zhao
    IMP, Lanzhou, People's Republic of China
  
  Funding: The supports by the National Natural Science Foundation of China (Grant No. 11275239 and 11221064) are gratefully acknowledged.
A new-concept injector for heavy ion synchrotrons, combined with a laser ion source, a Hybrid Single accelerator Chamber (HSC), has being developed based on Direct Plasma Inject Scheme (DPIS) at Institute of Modern Physics (IMP). The HSC is a linac integrating RFQ and DTL into a single chamber while costing partial matching efficiency between and the RFQ and DTL. Nevertheless, due to the capability of the laser ion source in producing intensive ion pulse and the advantage of DPIS, the intensity of the accelerated ion beam was still quite impressive. With this new-concept injector, C6+ ion beams could be accelerated to 2 MeV/u in less than 3 meters, which provides a possibility to use the most efficient single turn injection mode for filling of the synchrotrons rings. The preliminary results on the injector will be presented in this paper. And the investigation on the matching between the LIS and HSC, and that between RFQ and DTL part is still ongoing. 		 
 
TUPP015 Status on Airix Restart 462
 
  • A. Georges, J. Beaubernard, V. Bernigaud, L. Buche, Y. Collet, S. Combacon, B. Gouin, G. Grandpierre, J.K. Kranzmann, L. Magnin, R. Nicolas, D. Pierre, F. Poulet, Y. Tailleur, J-L. Verstraete, J. Magnan
    CEA, Pontfaverger-Moronvilliers, France
  
  The Airix accelerator has been moved from Moronvilliers to Valduc to be part of the EPURE facility. Airix has been refurbished and restarted. This paper presents the first results and quantification of performances at its new location.
*M.Mouillet et al., “First results of AIRIX induction accelerator”,XXth LINAC cf.,p.491(2000)
**H.Dzitko et al., "operationnal efficiency of Airix accelerator since its commissioning",IPAC2012,p.4017 		 
 
TUPP016
 Cornell ERL cavity production and vertical test results  
 
  • F. Furuta, B. Bullock, B. Clasby, R.G. Eichhorn, B. Elmore, A. Ganshin, G.M. Ge, G.H. Hoffstaetter, J.J. Kaufman, M. Liepe, J. Sears
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  The Cornell ERL 7-cell cavities for the Main Linac Cryomodule (MLC), six 7-cells in total- have been fabricated, processed, and tested in the Cornell Laboratory for Accelerator-based Sciences and Education (CLASSE) vertical test pit. All have surpassed the specification values (Eacc=16.2MV/m with Qo of 2.0·1010 at 1.8K). In fact, the achieved Qo during vertical test were much higher than specs, the average of Qo is almost 3·1010 at 1.8K. In this poster, we will describe about our ERL cavity fabrication, preparation, and vertical testing results.  
 
TUPP018 Analysis of Systematic and Random Error in SRF Material Parameter Calculations 465
 
  • S.J. Meyers, M. Liepe, S. Posen
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • M. Liepe
    Cornell University, Ithaca, New York, USA
  
  Funding: NSF Career award PHY-0841213 and DOE award ER41628
To understand the relationship between an RF cavity’s performance and the material on its surface, one must look at various parameters, including energy gap, mean free path, and residual resistance. Though SRIMP fits for seven parameters, three parameters are eliminated using measurement and literature values, and the uncertainty of the fit of the remaining four parameters is further reduced by synthesizing two 3-parameter fits, each from a different data set. To study random error, Monte Carlo simulations were performed of ideal data with added noise; for systematic error, contour plots of normalized residual sum of squares (RSS) of the polymorphic fit on inputted data were generated. 		 
poster icon Poster TUPP018 [1.183 MB]  
 
TUPP019 Qualification of the Titanium Welds in the E-XFEL Cryomodule and the CE Certification 468
 
  • S. Barbanotti, H. Hintz, K. Jensch, R. Klos, W. Maschmann, A. Matheisen, A. Schmidt
    DESY, Hamburg, Germany
  • C. Boulch, C. Cloué, C. Madec, J.L. Perrin, T. Trublet
    CEA/IRFU, Gif-sur-Yvette, France
  • J.-P. Charrier, O. Napoly
    CEA/DSM/IRFU, France
  
  The CE stamping of the one hundred 1.3 GHz cryomodules for the XFEL Linac is a main step in the process of the certification of the entire Linac as a pressure equipment. Stringent requirements on materials and the quality of the welds of the pressurised components need to be satisfied to obtain the stamp. This paper summarizes these requirements, describes the process developed to qualify each module and summarises the rework campaign on the cavity helium vessels made necessary to obtain the required quality for a reliable and safe accelerator.  
 
TUPP020 Beam Dynamics Simulation for FLASH2 HGHG Option 471
 
  • G. Feng, S. Ackermann, J. Bödewadt, W. Decking, M. Dohlus, Y.A. Kot, T. Limberg, M. Scholz, I. Zagorodnov
    DESY, Hamburg, Germany
  • K.E. Hacker
    DELTA, Dortmund, Germany
  • T. Plath
    Uni HH, Hamburg, Germany
  
  The free electron laser (FEL) facility at DESY in Hamburg (FLASH) is the world's first FEL user facility which can produce extreme ultraviolet (XUV) and soft X-ray photons. In order to increase the beam time delivered to users, a major upgrade named FLASH II is in progress. The electron beamline of FLASH2 consists of diagnostic and matching sections and a SASE undulator section. A seeding undulator section will be installed in the future. FLASH2 will be used as a seeded FEL as well as a SASE FEL. In this paper, some results of beam dynamics simulation for the SASE option are given at first which includes the parameters selection for the bunch compressors, RF parameters calculation for the accelerating modules and the beam dynamics simulation taking into account the collective effects. Beam dynamics simulation for a single stage HGHG option is based on the work for the SASE option. Electron bunches with low uncorrelated energy spread and small energy chirp are obtained after parameters optimization. The FEL simulation results show that 33.6 nm wavelength FEL radiation with high monochromaticity can be seeded at FLASH2 with a 235 nm seeding laser.  
 
TUPP021 A New Type of Waveguide Distribution for the Accelerator Module Test Facility of the European XFEL 475
 
  • V.V. Katalev, S. Choroba
    DESY, Hamburg, Germany
  • E.M. Apostolov
    MicroPlus-Apostolov Ltd., Sofia, Bulgaria
  • A.A. Seliverstov
    s.p.a. FERRITE Ltd., St.Petersburg, Russia
  
  In order to test 100 superconducting accelerator modules within two years three test benches have been created in the accelerator module test facility (AMTF) to achieve the rate of one cryomodule per week. Each RF station of the test facility consists of a 5 MW klystron, at 1.3 GHz, 1.37 ms pulse width and 10 Hz repetition rate, and a waveguide distribution system. Each waveguide distribution supplies RF power to eight cavities, four times a pair of cavities. The distribution allows for a maximum power of 1 MW per cavity when the distribution is switched to mode supplying power to only four cavities. A new type of 1 MW isolator and a new compact 5 MW power divider have been developed to achieve that goal. Several cryomodule have been already successfully tested with this setup. We present the waveguide distribution for this test stand and describe the performance of the different elements.  
 
TUPP022 RF Tuning of a S-band Hybrid Buncher for Injector Upgrade of LINAC II at DESY 478
 
  • Y.C. Nie, M. Hüning, C. Liebig, M. Schmitz
    DESY, Hamburg, Germany
  
  LINACII at DESY currently provides 450 MeV electrons for the synchrotron radiation source PETRAIII. The injector upgrade of it aims to improve its reliability and mitigate the radiological activation due to electron losses at hundreds of MeV. Therefore, a 2.998 GHz hybrid buncher has been developed and will be installed in between a pre-buncher and LINAC II. It comprises a 1-cell standing-wave (SW) section for rapid acceleration and a 13-cells travelling-wave (TW) section for further bunching and acceleration. This paper focuses on its rf tuning procedure. The tuning strategy combines a non-resonant bead-pull measurement of complex electric field and a linear model for local reflection coefficient calculation. The tuning result is satisfying. Field unflatness of the TW section has been improved from ±9% to ±4%, and field in the SW section has been enhanced significantly. By using ASTRA simulation, it has been verified that the residual detuning of the structure is acceptable in view of beam dynamics performance.  
 
TUPP023 Testing of the First Part of Series Production 10MW MBKs for the XFEL Project. 481
 
  • V. Vogel, Ł. Butkowski, A. Cherepenko, S. Choroba, J. Hartung, V.V. Kachaev, R. Wagner
    DESY, Hamburg, Germany
  
  At present more than half of 27 of 10 MW horizontal multi-beam klystrons (MBK) manufactured by two companies for the European XFEL project have been delivered to DESY. After delivery each klystron is connected to the connection module (CM), a HV oil tank with integrated HV connector, voltage and current monitors and a coaxial filament transformer, tested on the test stand and, if necessary conditioned. After this the klystrons are ready for installation in the underground linear accelerator tunnel. Two MBKs are already installed at the injector area of the XFEL. For the European XFEL project MBKs which can produce RF power of 10 MW, at RF frequency of 1.3 GHz, 1.5 ms pulse length and 10 Hz repetition rate, were chosen as RF power sources. During the incoming test the most important parameters of the MBK such as bandwidth, filament power, perveance, gain at different cathode voltage, phase stability and sensitivity to the solenoids current setting are measured and documented. In this paper we will give an overview of the test procedure, summarize the current test results and give a comparison of the most important parameters for several tubes.  
 
TUPP025 Progress on ESS Medium Energy Beam Transport 484
 
  • I. Bustinduy, D. Fernandez-Cañoto, N. Garmendia, A. Ghiglino, O. González, P.J. González, Z. Izaola, I. Madariaga, M. Magan, L. Muguira, J.L. Muñoz, I. Rueda, F. Sordo, S. Varnasseri, R. Vivanco
    ESS Bilbao, Bilbao, Spain
  • M. Eshraqi, R. Miyamoto, A. Ponton
    ESS, Lund, Sweden
  
  The considered versatile ESS MEBT is being designed to achieve four main goals: First, to contain a fast chopper and its correspondent beam dump, that could serve in the commissioning as well as in the ramp up phases. A detailed study of the chopper rise time effects on the loss budget will be presented. Second, to serve as a halo scraping section by means of various adjustable blades. Third, to measure the beam phase and profile between the RFQ and the DTL, along with other beam monitors. And finally, to match the RFQ output beam characteristics to the DTL input both transversally and longitudinally. For this purpose a set of eleven quadrupoles is used to match the beam characteristics transversally, combined with three 352.2 MHz CCL type buncher cavities, which are used to adjust the beam in order to fulfil the required longitudinal parameters. A thorough study on the optimal input beam parameters will be discussed. Quadrupole design update will be presented along with new RF measurements over the buncher prototype. Finally, updated results will be presented on the chopper and beam-dump system.  
poster icon Poster TUPP025 [5.596 MB]  
 
TUPP028 Beam Tests at the CLIC Test Facility, CTF3 487
 
  • R. Corsini, S. Döbert, W. Farabolini, D. Gamba, J.L. Navarro Quirante, T. Persson, P.K. Skowronski, F. Tecker
    CERN, Geneva, Switzerland
  • W. Farabolini
    CEA/DSM/IRFU, France
  • D. Gamba
    JAI, Oxford, United Kingdom
  
  The CLIC Test Facility CTF3 has been built at CERN by the Compact Linear Collider (CLIC) International Collaboration, in order to prove the main feasibility issues of the two-beam acceleration technology on which the collider is based. After the successful completion of its initial task, CTF3 is continuing its experimental program in order to give further indications on cost and performance issues, to act as a test bed for the CLIC technology, and to conduct beam experiments aimed at mitigating technological risks. In this paper we discuss the status of the ongoing experiments and present the more recent results, including improvements in beam quality and stability.  
 
TUPP029 Diagnostics and Analysis Techniques for High Power X-Band Accelerating Structures 490
SUPG002   use link to see paper's listing under its alternate paper code  
 
  • A. Degiovanni, S. Döbert, W. Farabolini, I. Syratchev, W. Wuensch
    CERN, Geneva, Switzerland
  • J. Giner Navarro
    IFIC, Valencia, Spain
  • J. Tagg
    National Instruments Switzerland, Ennetbaden, Switzerland
  • B.J. Woolley
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  
  The study of high gradient limitations due to RF breakdowns is extremely important for the CLIC project. A series of diagnostic tools and analysis techniques have been developed in order to monitor and characterize the behaviour of CLIC accelerating structures under high power operation in the first CERN X-band klystron-based test stand (Xbox1). The data collected during the last run on a TD26r05 structure are presented in this paper. From the analysis of the RF power and phases, the location of the breakdowns inside the structure could be determined. Other techniques based on the field emitted dark current signals collected by Faraday cups placed at the two extremities of the structure have also been investigated. The results of these analyses are reported and discussed.  
 
TUPP030 Design of a High Average Current Electron Source for the CLIC Drive Beam Injector 493
 
  • S. Döbert, N. Chritin
    CERN, Geneva, Switzerland
  • B. Cadilhon, B. Cassany, J. Gardelle, K. Pepitone
    CEA, LE BARP cedex, France
  
  The drive beam injector for CLIC needs to deliver a 4.2 A electron beam for a duration of 140 μs with a repetition rate of 50 Hz. The shot to shot and flat top current stability has to be better than 0.1% to guarantee the beam stability required for CLIC. Based on the experience with the CTF3 injector a thermionic high voltage gun with a gridded cathode has been designed together with a sub-harmonic bunching system to achieve these requirements. The grid will allow controlling the current and eventually feedback on the flattop shape. The gun will operate at 140 kV and an emittance of 14 mm mrad can be obtained. The paper describes the design approach and the results of the systematic electromagnetic simulations to optimize the gun. Care was taken during the mechanical design of the gun to obtain a modular design allowing adjusting for different beam currents and cathode sizes.  
 
TUPP031 Understanding the Error Tolerances Required to Automatically Phase the HIE-ISOLDE Linac 496
 
  • M.A. Fraser, J.C. Broere, S. Haastrup, D. Lanaia, D. Valuch, D. Voulot
    CERN, Geneva, Switzerland
  
  The broad experimental programme at ISOLDE means that the same radioactive beam species and energy are rarely studied twice and the cavities of the linac must be scaled or re-phased for each experiment. A software application was developed to automatically re-phase the cavities of the HIE-ISOLDE superconducting linac to the beam from computed settings. The application was developed to expedite both machine set-up in normal operation and in scenarios involving cavity failures. A beam dynamics error study will be presented in order to better understand the challenges facing the automatic phasing routine. The effects of a variety of different errors on the efficacy of the phasing application were studied, leading to a specification of the tolerances required for the calibration of the rf system and the accuracy of the survey system that monitors the positions of the cavities.  
 
TUPP033 Effect of Beam-Loading on the Breakdown Rate of High Gradient Accelerating Structures 499
TUPOL08   use link to see paper's listing under its alternate paper code  
 
  • J.L. Navarro Quirante, R. Corsini, A. Degiovanni, S. Döbert, A. Grudiev, O. Kononenko, G. McMonagle, S.F. Rey, A. Solodko, I. Syratchev, F. Tecker, L. Timeo, B.J. Woolley, X.W. Wu, W. Wuensch
    CERN, Geneva, Switzerland
  • O. Kononenko
    SLAC, Menlo Park, California, USA
  • A. Solodko
    JINR, Dubna, Moscow Region, Russia
  • J. Tagg
    National Instruments Switzerland, Ennetbaden, Switzerland
  • B.J. Woolley
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • X.W. Wu
    TUB, Beijing, People's Republic of China
  
  The Compact Linear Collider (CLIC) is a study for a future room temperature electron-positron collider with a maximum center-of-mass energy of 3 TeV. To efficiently achieve such high energy, the project relies on a novel two beam acceleration concept and on high-gradient accelerating structures working at 100 MV/m. In order to meet the luminosity requirements, the break-down rate in these high-field structures has to be kept below 10 per billion. Such gradients and breakdown rates have been demonstrated by high-power RF testing several 12 GHz structures. However, the presence of beam-loading modifies the field distribution for the structure, such that a higher input power is needed in order to achieve the same accelerating gradient as the unloaded case. The potential impact on the break-down rate was never measured before. In this paper we present an experiment located at the CLIC Test Facility CTF3 recently proposed in order to quantify this effect, layout and hardware status, and discuss its first results.  
slides icon Slides TUPP033 [1.970 MB]  
poster icon Poster TUPP033 [2.355 MB]  
 
TUPP034 Commissioning of the CERN LINAC4 Wire Scanner, Wire Grid and Slit-Grid Monitors at 3 and 12 MeV 502
 
  • F. Roncarolo, U. Raich, F. Zocca
    CERN, Geneva, Switzerland
  
  The CERN LINAC4 has been commissioned up to 12 MeV. The H− beam transverse profile distributions were measured by both wire grids and wire scanners. A slit-grid system located on a temporary diagnostics bench was used to characterize the transverse emittance during the two different stages of commissioning: at the exit of the RFQ (3 MeV) and DTL1 (12 MeV). The wire signal is a balance between the negative charge deposited by the stripped electrons from the H− and the charge lost due to secondary emission. Optimal settings were found for the repelling plates used to suppress secondary emission, which were confirmed by electromagnetic simulations. In addition, suppression of the secondary emission due to the beam space charge was observed. The benefit of changing the wire scanner geometry in order to minimize the cross-talk between horizontal and vertical wires and the observation of thermionic emission on carbon wires are also discussed.  
 
TUPP035 Transverse Profile and Emittance Measurements With a Laser Stripping System During the CERN LINAC4 Commissioning at 3 and 12 MeV 506
 
  • F. Roncarolo, E. Bravin, T. Hofmann, U. Raich, F. Zocca
    CERN, Geneva, Switzerland
  • G.E. Boorman, A. Bosco, S.M. Gibson, K.O. Kruchinin
    Royal Holloway, University of London, Surrey, United Kingdom
  • C. Gabor
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  The CERN LINAC4 beam commissioning at 3 and 12 MeV was completed in 2014. A novel system for measuring the transverse beam profile and emittance, based on low power laser stripping and H0 detection using a diamond detector, was successfully tested at these two energies. The measurement results agree with the operational slit-grid method within a few percent in terms of both transverse profile and emittance. After describing the general system setup, this remarkable achievement is discussed in detail together with the present limitations, which will be addressed in order to design a laser based emittance monitor for the LINAC4 top energy of 160 MeV.  
 
TUPP036 Space Charge Compensation in the Linac4 LEBT for Three Injected Gas Types 510
TUPOL012   use link to see paper's listing under its alternate paper code  
SUPG028   use link to see paper's listing under its alternate paper code  
 
  • C.A. Valerio, R. Scrivens
    CERN, Geneva, Switzerland
  • N. Chauvin
    CEA/IRFU, Gif-sur-Yvette, France
  
  The space charge of unbunched, high intensity beams can be compensated by the trapping of charged particles in the potential well of the beam. The source of these secondary charge particles can be the residual gas in the beam line. The effect is important in the Low energy beam transport (LEBT) regions. At CERN’s Linac4, the LEBT transports a pulsed 45keV H− beam, which is compensated by the positive ions, created by collision of the beam with the neutral gas in the beam pipe. The rise time and amount of compensation may be varied by the density of neutral gas and the type of gas used (through the cross-section for ion production and the mass of the resulting ion). In this paper we present measurement results for the transport of the beam at the Linac4 LEBT with the addition of hydrogen, nitrogen and krypton gases into the line, and compare them with simulations of the beam dynamics including the effect of compensating positive ions . The H− beam is provided by a cesiated 2MHz RF ion source with an external solenoidal antenna, operating with 600us pulses at 0.8Hz repetition rate.  
slides icon Slides TUPP036 [4.084 MB]  
poster icon Poster TUPP036 [1.356 MB]  
 
TUPP037 Transverse Emittance Measurements of the REX-ISOLDE Beams in Preparation for the HIE-ISOLDE Commissioning 513
 
  • D. Voulot, M.A. Fraser, D. Lanaia
    CERN, Geneva, Switzerland
  • T. Olsson
    MAX-lab, Lund, Sweden
  
  The transverse emittance at the output of the REX-ISOLDE normal conducting linac has been measured at different energies in order to characterise the beam at injection to the future HIE-ISOLDE superconducting linac. The measurements were done with low intensity stable beams (~0.5 enA) in order to avoid compensation effects in the EBIS ion source and obtain representative measurements of the radioactive ion beam emittance. Emittances were measured using a slit-grid emittance meter and compared with results obtained with a quadrupole-scan (three-gradient) method. An analysis of the background suppression is presented and possible source of errors for both type of measurements are discussed.  
poster icon Poster TUPP037 [2.084 MB]  
 
TUPP038 Transverse Beam Profile Measurements in the Linac4 Medium Energy Beam Transport 516
SUPG029   use link to see paper's listing under its alternate paper code  
 
  • M. Yarmohammadi Satri, G. Bellodi, V.A. Dimov, J.-B. Lallement, A.M. Lombardi, U. Raich, F. Roncarolo, F. Zocca
    CERN, Geneva, Switzerland
  
  Linac4 is a 160 MeV H− linear accelerator presently under construction at CERN. It will replace the present 50 MeV proton Linac2 as injector of the proton accelerator complex as part of a project to increase the LHC luminosity. The Linac4 front-end, composed of a 45 keV ion source, a Low Energy Beam Transport (LEBT), a 352.2 MHz Radio Frequency Quadrupole (RFQ) which accelerates the beam to 3 MeV and a Medium Energy Beam Transport (MEBT) housing a beam chopper, has been commissioned in the Linac4 tunnel. The MEBT is composed of three buncher cavities and 11 quadrupole magnets to match the beam from the RFQ to the next accelerating structure (DTL) and it includes two wire scanners for beam profile measurement. In this paper we present the results of the profile measurements and we compare them with emittance measurements taken with a temporary slit-and-grid emittance measurement device located after the MEBT line.  
 
TUPP039 Accuracy Determination of the ESS MEBT Emittance Measurements 519
 
  • B. Cheymol, A. Ponton
    ESS, Lund, Sweden
  
  The European Spallation Source MEBT will be equipped with a full set of diagnostics in order to characterize the bean properties before the injection in the DTL. The 6D phase space of the beam shall be characterize during the commissioning of the normal conducting as well as on regular basis during retuning phase of the machine. In this paper we will discuss the accuracy of the transverse emittance measurement that will be performed with the slit-grid method. The slit geometric parameters have been determined in order to achieve the required resolution and sensitivity. Scattering effects at the slit have been considered to determine the emittance measurement accuracy.  
 
TUPP040 Preliminary Functional Analysis of ESS Superconducting Radio-Frequency Linac 522
 
  • C. Darve, N. Elias, J. Fydrych, D.P. Piso
    ESS, Lund, Sweden
  
  The European Spallation Source (ESS) is one of Europe's largest planned research infrastructures. The collaborative project is funded by a collaboration of 17 European countries and is under design and construction in Lund, Sweden. Three families of Superconducting Radio-Frequency (SRF) cavities are being prototyped, counting the spoke resonators with a geometric beta of 0.5, medium-beta elliptical cavities (βg=0.67) and high-beta elliptical cavities (bg=0.86). The 5 MW, 2.86 ms long pulse proton accelerator has a repetition frequency of 14 Hz (4 % duty cycle), and a beam current of 62.5 mA. The cavities and power couplers are assembled into cryomodules, which are operating using RF sources, cryogenic and water coolings. This document describes the process of the ESS SRF cryomodule operation while refereeing to operational modes.  
 
TUPP041 Beam Current Monitor System of the European Spallation Source 526
 
  • H. Hassanzadegan, M. Donna, A. Jansson, H. Kocevar, A. Nordt
    ESS, Lund, Sweden
  • U. Legat
    Cosylab, Ljubljana, Slovenia
  • M. Werner
    DESY, Hamburg, Germany
  
  The Beam Current Monitor system of the ESS will be primarily used for beam current and charge measurements in absolute and differential modes. Moreover, it will provide a fast input to the Beam Interlock System, initiating a trigger to shut the beam off upon high beam loss detection. As the BCM system will be needed at an early stage for Linac commissioning, it needs to work successfully under non-optimal conditions, ex. short pulse and low current beams. It is planned to install in total 20 AC Current Transformers and one Fast Current Transformer along the Linac. The FCT will have a larger bandwidth and it will be used to measure the performance of the fast chopper of the Medium Energy Beam Transport with a rise time of 10 ns. A prototype based on a commercial ACCT and EPICS-integrated MTCA.4 electronics has been set up and successfully tested with an emulated beam. The ACCT signal has been FPGA processed to compensate for the offset and droop as well as filtering and synchronization to an external trigger. This paper gives an overview of the design and test results of the prototype ACCT system with an outlook to future modifications before installation in the ESS Linac.  
poster icon Poster TUPP041 [6.113 MB]  
 
TUPP043 Design of the Phase Reference Distribution System at ESS 529
 
  • R. Zeng, H. Hassanzadegan, M. Jensen, J.M. Jurns, O.A. Persson, A. Sunesson
    ESS, Lund, Sweden
  • K. Strniša
    Cosylab, Ljubljana, Slovenia
  
  PRDS (Phase reference distribution system) at ESS will provide phase reference signals for all LLRF systems and BPM systems with low phase noise and low phase drift. Phase stability requirement is currently 0.1° for short term (during pulse), 1° for long term (days to months). There are 155 LLRF systems and 165 BPM systems in total at current ESS accelerator design.  
 
TUPP044
 Validation of FRIB SRF Coaxial Resonators at MSU  
 
  • J. Popielarski, K. Elliott, A. Facco, M. Hodek, D. Norton, J.P. Ozelis, A.P. Rauch, K. Saito, G.J. Velianoff, K. Witgen
    FRIB, 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
Michigan State University is currently testing production cavities as part of final validation of fully dressed 80.5 MHz β=0.085 quarter wave resonators (QWR) and β=0.53 half wave resonators (HWR), which are being produced for a driver linac for the Facility for Rare Isotope Beams. This paper updates the developments for the FRIB and ReA resonators as preparations at MSU are being made for production runs. 		 
 
TUPP045 Beam Physics Challenge in FRIB Driver Linac 532
TUPOL04   use link to see paper's listing under its alternate paper code  
 
  • Y. Yamazaki, N.K. Bultman, A. Facco, Z.Q. He, M. Ikegami, M.J. Johnson, S.M. Lidia, F. Marti, G. Pozdeyev, K. Saito, J. Wei, X. Wu, Y. Zhang, Q. Zhao
    FRIB, East Lansing, Michigan, 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 driver linac provides CW beams of all the stable ions (from protons to uranium) with a beam power of 400 kW and a minimum beam energy of 200 MeV/u in order to produce a wide variety of rare isotopes, mainly for nuclear physics study. The low beam emittances, both transverse and longitudinal, are key performance requirements, together with beam stability. These are required for efficiently separating one isotope from another, the reason for choosing this linac configuration. Multi-charge states (five charge states for the uranium case) are accelerated for maximizing the beam current, while keeping the low emittances. The efficient acceleration of high beam currents from 0.5 MeV/u through the superconducting linac is, needless to say, one of the biggest challenges. The beam power is more than 200 times higher than existing similar SC heavy ion linac. In particular, the SC cavities are difficult to protect from heavy ion beam damage, which can be 30 times larger locally than a proton beam with the same beam power. Other challenges peculiar to the FRIB linac will be presented, together with the solutions. 		 
 
TUPP046
 Design comparison between combined and separate function magnets in the FRIB bending sections  
 
  • Q. Zhao
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The double-folded FRIB driver linac will accelerate ion beams with multiple charge states simultaneously to maximize output beam power. Therefore, the two 180-degree bending sections, connecting the three superconducting linac segments, are designed to transport beam achromatically and isochronously. Quadrupoles combined with sextupoles were used in the previous design to save space in the tight bending sections. Further detailed design show these combined function magnets were complicated. We thus revisited the design recently with separate function magnets. In this paper, we will compare the design between the two schemes, present the beam simulation results. We will also discuss the optimization procedures on the design of the new separate function magnets. 		 
 
TUPP047 PXIE RFQ Bead Pull Measurements 535
 
  • P. Berrutti, T.N. Khabiboulline, V. Poloubotko, G.V. Romanov, J. Steimel, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  • D. Li, J.W. Staples
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359
Project X Injector Experiment radio frequency quadrupole has recently been built for Fermilab by Berkley laboratory. This RFQ will be placed after the low energy beam transport (LEBT) and before the medium energy beam transport (MEBT). The RFQ will operate at 162.5 MHz in CW regime; its function is to accelerate and focus particles coming from the LEBT at 30 keV, and to deliver a beam at 2.1 MeV to the MEBT. In order to make sure that the RFQ meets the specifications of field flatness and frequency the field in the vanes should be measured using bead pull technique. FNAL created a new single wire bead pull set up for the RFQ of PXIE. The measurements are used to find the electrical center of the structure, then the amplitude of the electromagnetic field in all the sectors of the RFQ; and the tuning will be based on these measurements. This paper describes the bead pull experimental set up, the software developed for this particular application and the measurements taken. 		 
poster icon Poster TUPP047 [1.089 MB]  
 
TUPP049 Test Stand for 325 MHz Power Couplers 538
 
  • S. Kazakov, B.M. Hanna, T.N. Khabiboulline, V. Poloubotko, O.V. Pronitchev, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  325 MHz superconducting Single Spoke resonators (SSR1) will be utilized in the Project X Injector Experiment (PXIE). Developed in Fermilab the main power coupler will be supply 2kW CW RF power to each cavity. Fermilab developed and designed the special test stand where the couplers will be tested up to 10 kW and design properties be confirmed. This paper describes the design of the coupler test stand and preliminary results of the tests.  
 
TUPP052 SSR1 Tuner Mechanism: Passive and Active Device 541
SUPG008   use link to see paper's listing under its alternate paper code  
 
  • D. Passarelli
    Fermilab, Batavia, Illinois, USA
  
  In this paper we present the methodology adopted in designing the mechanism responsible for controlling the resonant frequency of Single Spoke Resonators of first type (SSR1). Such device is capable of compensating the effects of external perturbations, such as pressure fluctuations and microphonics, on the frequency of SSR1. The compensation is achieved through active responses via an actuation system and passive responses which are inherent to the elastic behavior of the overall system. The first experiences in the design, assembly, QA and testing are reported.  
poster icon Poster TUPP052 [2.368 MB]  
 
TUPP053
 Test of Electromechanical Actuators for SRF Cavity Tuners  
 
  • Y.M. Pischalnikov, C.J. Grimm, R.V. Pilipenko
    Fermilab, Batavia, Illinois, USA
  • H. Brunke, W. Lahmadi
    Phytron, Waltham, Massachusetts, USA
  
  SRF cavities required slow tuner. Major component of slow tuner is electromechanical actuator based stepper motor/gear system/spindle & nut. Failures of the electromechanical actuators made significant impact on operation of the linear accelerators. Fermilab is designing linear accelerator for PIP II. 325MHz and 650MHz SRF cavities, which designed to work at PIP II linac, have large stiffness. FNAL and Phytron developed electromechanical actuator based on stepper motor/gear system/shaft as a component for tuners to serve SRF cavities for PIP II linac. Results of the cold test of the actuators prototypes mounted on the SRF cavity presented. Review of reliabilities for available on the market electromechanical actuator presented.  
 
TUPP054 Study of Beam-Based Alignment for the LCLS-II SC Linac 544
 
  • A. Saini, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  • T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  
  The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of 4 GeV superconducting (SC) linac. The achievable performance of linac is determined by beam sensitivity to various component errors. In this paper we review misalignment tolerances of LCLS-II SC linac and discuss possible beam-based alignment algorithm to meet these tolerances.  
 
TUPP055 Progress on Euclid SRF Conical Half-Wave Resonator Project 547
 
  • E.N. Zaplatin
    FZJ, Jülich, Germany
  • T.L. Grimm
    Niowave, Inc., Lansing, Michigan, USA
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Funding: This Work is supported by the DOE SBIR Program, contract # DE-SC0006302.
Euclid conical Half-Wave Resonator (cHWR) project develops 162.5 MHz β=v/c=0.11 accelerator structure for the high-intensity proton accelerator complex proposed at Fermi National Accelerator Laboratory. The main idea of this project is to provide a self-compensation cavity design together with its helium vessel to minimize the resonant frequency dependence on external loads. A unique cavity side-tuning option is also under development. Niowave, Inc. proposed a complete cavity production procedure including preparation of technical drawings, processing steps and resonator high-gradient tests to demonstrate such possibility for the private company. Here we present the procedure of the cavity and helium vessel fabrication, cavity preparation and initial experimental results. 		 
 
TUPP056 High Current Proton Beam Operation at GSI UNILAC 550
 
  • W.A. Barth, A. Adonin, P. Gerhard, M. Heilmann, R. Hollinger, W. Vinzenz, H. Vormann
    GSI, Darmstadt, Germany
  
  A significant part of the experimental program at FAIR is dedicated to pbar physics requiring a high number of cooled pbars per hour. The primary proton beam has to be provided by a 70 MeV proton linac followed by two synchrotrons. The new FAIR Proton LINAC will deliver a pulsed proton beam of up to 35 mA of 36 μs duration at a repetition rate of 4 Hz. The current GSI heavy ion linac (UNILAC) is able to deliver world record uranium beam intensities for injection into the synchrotrons, but it is not dedicated for FAIR relevant proton beam operation. In an advanced machine investigation program it could be shown, that the UNILAC is able to provide for sufficient high intensities of CH3-beam, cracked (and stripped) in a supersonic nitrogen gas jet into protons and carbon ions. This advanced operational approach results in up to 2 mA of proton intensity at a maximum beam energy of 20 MeV, 100 μs pulse duration and a rep. rate of 4 Hz. Recent linac beam measurements will be presented, showing that the UNILAC is able to serve as a proton FAIR injector for the first time, while the performance is limited to 17% of the FAIR requirements.  
 
TUPP057 In Situ Measurement of Mechanical Vibrations of a 4-Rod RFQ at GSI 553
 
  • P. Gerhard, L. Groening, K.-O. Voss
    GSI, Darmstadt, Germany
  
  A new 4-rod CW Radio Frequency Quadrupole was commissioned at the high charge state injector HLI at the UNILAC in 2009. It is in operation since 2010*. At high rf amplitudes strong modulations of the rf reflection emerge, with a modulation frequency of approximately 500 Hz. They are attributed to mechanical oscillations of the rods, excited by the rf pulse. The high fraction of reflected rf power severely limits the pulse length and rf amplitude achievable. As these modulations could only be seen during the rf pulse by means of rf measurements, a direct observation of the mechanical vibrations was desirable. Such measurements have been conducted using a commercial laser vibrometer, allowing for the investigation of the mechanical behavior of the RFQ independent of the presence of rf power. After a short introduction of the method, the results will be presented and compared with rf measurements and simulations.
*: P. Gerhard et al., “Experience with a 4–Rod CW RFQ”, LINAC’12, Sept. 2012, Tel Aviv, THPB035 		 
 
TUPP058 RF System Development for the New 108 MHz Heavy Ion High-Energy Linac at GSI 556
 
  • B. Schlitt, M. Hoerr, A. Schnase, G. Schreiber, W. Vinzenz
    GSI, Darmstadt, Germany
  
  The GSI UNILAC is in operation successfully since about 40 years. A replacement of the post stripper section is proposed to provide heavy ion beams for the future FAIR facility. Design studies for a new 108 MHz high-energy (HE) linac optimized to accelerate high brilliance and high current ion beams up to U28+ for synchrotron injection are in progress. Thus, the UNILAC will be converted into a short-pulse accelerator, the RF duty cycle being reduced from around 30 % to <2 %. To feed the future HE linac and to prepare for the FAIR commissioning, a major modernisation of the existing post stripper RF systems is planned from 2015 to 2017. Besides, the development of a new 1.8 MW cavity amplifier prototype was started recently, based on the widely-used THALES tetrode TH558SC promising an availability for at least 25 years. New 120 - 150 kW solid state driver amplifiers will replace the existing tube drivers. A digital LLRF system designed by industry was integrated into an existing amplifier driving a single gap resonator and was tested including ion beam tests. An overview of the RF system design and of the planned upgrades will be reported including some results of the LLRF tests.  
 
TUPP059 Advanced Beam Matching to a High Current RFQ 559
 
  • S.G. Yaramyshev, W.A. Barth, L.A. Dahl, P. Gerhard, L. Groening, M.T. Maier, S. Mickat, A. Orzhekhovskaya, B. Schlitt, H. Vormann
    GSI, Darmstadt, Germany
  
  The High Current Injector (HSI) of the heavy ion linac UNILAC at GSI comprises the transport lines, the RFQ and two DTL tanks. Beam matching to the RFQ acceptance with a magnetic quadrupole quartet has been worked out manually during commissioning and operation of the machine. Due to a strong overlapping of the field from neighboring quadrupole lenses, a standard optics calculation does not provide for the required reliability. Advanced beam dynamics simulations have been done with the macroparticle code DYNAMION. The superposition of the measured magnetic fields of each quadrupole was taken into account. The quadrupole settings were optimized using the Monte-Carlo method. Two solutions have been found in accordance with the general theory of particle optics. Beam dynamics simulations with new quadrupole settings show an increased particle transmission through the RFQ. The results of numerical study have been confirmed during experimental campaigns. An improved performance of the whole HSI has been demonstrated. The proposed algorithm and a comparison of the measured data with result of simulations are presented.  
 
TUPP060 Development of a 217 MHz Superconducting CH Structure 563
SUPG009   use link to see paper's listing under its alternate paper code  
 
  • M. Basten, M. Amberg, M. Busch, F.D. Dziuba, D. Mäder, H. Podlech
    IAP, Frankfurt am Main, Germany
  • M. Amberg, K. Aulenbacher, W.A. Barth, S. Mickat
    HIM, Mainz, Germany
  • W.A. Barth, S. Mickat
    GSI, Darmstadt, Germany
  
  Funding: Helmholtz-Institut Mainz, Bundesministerium für Bildung und Forschung contract number 05P12RFRBL
To compete in the production of Super Heavy Elements (SHE) in the future a 7.3 AMeV superconducting (sc) continuous wave (cw) LINAC is planned at GSI. The baseline design consists of 9 sc Crossbar-H-mode (CH) cavities operated at 217 MHz. Currently an advanced cw demonstrator is under design at the Institute for Applied Physics (IAP) at Frankfurt University. The purpose of the advanced demonstrator is to investigate a new concept for the superconducting CH structures. It is based on shorter CH-cavities with 8 equidistant gaps without girders and with stiffening brackets at the front and end cap to reduce the pressure sensitivity. One major goal of the advanced demonstrator is to show that the new design leads to higher acceleration gradients and smaller Ep/Ea values. In this contribution first simulation results and technical layouts will be presented. 		 
poster icon Poster TUPP060 [0.593 MB]  
 
TUPP062 A Rebunching CH Cavity for Intense Proton Beams 566
SUPG011   use link to see paper's listing under its alternate paper code  
 
  • M. Schwarz, C. Claessens, M. Heilmann, O. Hinrichs, D. Koser, O. Meusel, D. Mäder, H. Podlech, U. Ratzinger, A. Seibel
    IAP, Frankfurt am Main, Germany
  
  Funding: Project supported by the EU, FP7 MAX, Contract No. 269565
The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) will provide ultra short neutron pulses at high intensities and repetition rates. The facility is currently under construction at the Goethe-University in Frankfurt am Main (Germany). A 5-Gap CH rebuncher is installed behind a coupled RFQ/IH-DTL combination at the end of the LINAC section between two magnetic quadrupole triplets. It will be used for varying the final proton energy as well as for focusing the bunch longitudinally to compensate huge space charge forces at currents up to 200 mA at the final stage of extension. High current beam dynamic simulations have been performed. They include benchmarking of different beam dynamic codes like LORASR and TraceWin, as well as validating the results by measurements. Detailed examination of multipole field impact, due to the cavity’s geometry, together with error tolerance studies and thermal simulations are also performed. Furthermore, this CH rebuncher serves as a prototype for rt CH cavities at MYRRHA (Belgium), an Accelerator Driven System for transmutation of high level nuclear waste. After copper plating the cavity, RF conditioning will start soon. 		 
poster icon Poster TUPP062 [6.015 MB]  
 
TUPP063 Improvements of the LORASR Code and their Impact on Current Beam Dynamics Designs 569
 
  • R. Tiede, D. Mäder, N.F. Petry, H. Podlech, U. Ratzinger, C. Zhang
    IAP, Frankfurt am Main, Germany
  
  LORASR is a multi-particle tracking code optimized for the beam dynamics design of ‘Combined Zero Degree Structure (KONUS)’ lattices, which can benefit from an adapted input file structure and code architecture. Recent code developments focused on the implementation of tools for machine error studies and loss profile investigations, including also steering correction strategies. These tools are a stringent necessity for the design of high intensity linacs. Thus, the abilities of the present LORASR release allow performing a manifold of checks and optimizations before finalizing the layouts of KONUS-based or conventional linacs. Two representative examples are the MAX-MYRRHA Injector and the GSI FAIR Facility Proton Linac, both under development with strong participation of IAP, Frankfurt University. This paper presents the status of the LORASR code development with focus on the new features and illustrates the impact on current designs by examples taken from the above-mentioned projects.  
 
TUPP064 Zero-Current Longitudinal Beam Dynamics 572
 
  • J.-M. Lagniel
    GANIL, Caen, France
  
  In linacs, the longitudinal focalization is done by nonlinear forces and the acceleration induces a damping of the phase oscillations. The longitudinal beam dynamics is therefore complex, even when the nonlinear space-charge forces are ignored. The three different ways to study and understand this zero-current longitudinal beam dynamics will be presented and compared.  
 
TUPP065 RF Input Power Couplers for High Current SRF Applications 575
TUPOL011   use link to see paper's listing under its alternate paper code  
 
  • V.F. Khan, W. Anders, A. Burrill, J. Knobloch, O. Kugeler, A. Neumann
    HZB, Berlin, Germany
  • H. Wang
    JLab, Newport News, Virginia, USA
  
  High current SRF technology is being explored in present day accelerator science. The BERLinPro project is presently being built at the HZB to address the challenges involved in high current SRF machines. A 100 mA electron beam is designed to be accelerated to 50 MeV in continuous wave (cw) mode at 1.3 GHz. One of the main challenges in this project is that of handling high input RF power for the gun as well as booster cavities where there is no energy recovery process. A high power co-axial input coupler is being developed to be used for the booster and gun cavities at the nominal beam current. The coupler is based on the KEK–cERL coupler design. The KEK coupler design has been modified to minimise the penetration of the tip in the beampipe without compromising on beam-power coupling ( Qext ~1 x 105). Herein we report on the RF design for the high power (130 kW) BERLinPro (BP) couplers along with the test stand for conditioning the couplers. We will also report on the RF conditioning of the TTF-III couplers modified for cw operation (low power ~ 10 kW) which will be utilised in a new 4-mA SRF Photoinjector and the BERLinPro main linac cryomodule.  
slides icon Slides TUPP065 [2.465 MB]  
 
TUPP066 Commissioning Results of the 2nd 3.5 Cell SRF Gun for ELBE 578
 
  • A. Arnold, M. Freitag, P. Murcek, J. Teichert, H. Vennekate, R. Xiang
    HZDR, Dresden, Germany
  • G. Ciovati, P. Kneisel, L. Turlington
    JLab, Newport News, Virginia, USA
  
  As in 2007 the first 3.5 cell superconducting radio frequency (SRF) gun was taken into operation at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), it turned out that the specified performance to realize an electron energy gain of 9.4 MeV (Epk=50 MV/m @ Q0=1010) has not been achieved. Instead, the resonator of the gun was limited by field emission to about one third of these values and the measured beam parameters remained significantly behind the expectations. However, to demonstrate the full potential of this new electron source for the ELBE LINAC, a second and slightly modified SRF gun was developed and built in collaboration with Thomas Jefferson National Accelerator Facility (TJNAF). We will report on commissioning and first results of this new SRF gun. This includes in particular the characterization of the most important RF properties of the cavity as well as their comparison with previous vertical test results.  
poster icon Poster TUPP066 [1.220 MB]  
 
TUPP067 Chopper Operation for the Tandem Scrapers at the J-PARC Linac 581
 
  • K. Futatsukawa, Z. Fang, Y. Fukui, T. Kobayashi, S. Michizono
    KEK, Ibaraki, Japan
  • E. Chishiro, K. Hirano, F. Sato, S. Shinozaki
    JAEA/J-PARC, Tokai-mura, Japan
  
  In the J-PARC linac, the energy upgrade from 181 MeV to 400 MeV by the installation of annular-ring coupled structure (ACS) cavities was successfully achieved in 2013. In the next stage, we will schedule the intensity upgrade by the increase of the beam current by improving the front-end in this summer. Then, the high heat load of the scraper, which stops the kicked-beam by the RF chopper, is predicted to damage the surface. Therefore, we prepare the tandem scrapers to suppress the heat load. The half of the kicked beam leads to a scraper and the residual is to the other. Its chopping expedient will be achieved by reversing the phase of the RF chopper on the periodic cycle at the low-level RF system. In this paper, I would like to introduce this system and present the result of the low-level test.  
 
TUPP068 New SRF Facility at KEK for Mass-Production Study in Collaboration with Industries 584
 
  • H. Hayano
    KEK, Ibaraki, Japan
  
  The construction of the new SRF facility next to the KEK-STF facility has started from 2014 for the mass-production study of SRF accelerators in collaboration with industries. The new building for this facility has the dimension of 80 m x 30 m, and the plan is to install clean-room for cavity-string assembly, cryomodule-assembly facility, cryogenic system, vertical test facility, cryomodule test facility, input coupler process facility, cavity Electro-Polishing (EP) facility, and control-room/office-rooms in it. The purpose of this new SRF facility is to establish a close collaboration between SRF researchers and industries in order to prepare for the upcoming large-scale future SRF project, like ILC. This paper describes the infra-structure detail and the plan to utilize for future SRF accelerators.  
 
TUPP070 Status and Recent Modifications to 324-MHz RF Source in J-PARC LINAC 587
 
  • M. Kawamura, Y. Fukui, K. Futatsukawa, F. Naito
    KEK, Ibaraki, Japan
  • E. Chishiro, K. Hasegawa, F. Sato, S. Shinozaki
    JAEA/J-PARC, Tokai-mura, Japan
  • T. Hori
    JAEA, Ibaraki-ken, Japan
  
  This paper describes the present status of and the recent modifications to the 324-MHz RF source in the J-PARC linac. The recovery from the Great East Japan Earthquake Disaster, the status of the 324-MHz klystrons, the failure of 3 high-voltage transformers (HVTRs), and the discharge suppression for the anode-modulators are described.  
poster icon Poster TUPP070 [0.660 MB]  
 
TUPP071 Vortex-Penetration Field at a Groove with a Depth Smaller than the Penetration Depth 590
 
  • T. Kubo
    KEK, Ibaraki, Japan
  
  Analytical models of the magnetic field enhancement at pits were presented at SRF2013 last year. In this presentation, I will show updated models.
proceedings of SRF 2013, Paris, France (2013), p. 430 		 
 
TUPP072 Studies on Wake Field in Annular Coupled Structure 593
 
  • Y. Liu, T. Maruta
    KEK/JAEA, Ibaraki-Ken, Japan
  • K. Futatsukawa
    KEK, Ibaraki, Japan
  • A. Miura
    JAEA/J-PARC, Tokai-mura, Japan
  
  LINAC injector of J-PARC (Japan Proton Accelerator Research Complex) was recently successfully upgraded from 181 MeV to 400 MeV, applying a type of coupled cavity linac (CCL) structure ACS (Annular Coupled Structure). It was warmly discussed since very beginning on the wake field in the ACS cavities, where there are CCL modes with the same number as that of cells within ~50 MHz, possibly resonating with high intensity proton/H− beams. One of the most important effects from the wake field is the influence on the ACS phase scan. Analytical and simulation studies, as well as the countermeasures were prepared before the energy upgrade. Fortunately we found that detuning of the ACS was unnecessary, which helped to save much work in the commissioning. In addition we got chance to make experiment studies. It was also discussed why the wake field is not so serious as we expected at the very beginning.  
 
TUPP073 Study of the ACS Cavity Without a Bridge Cavity 596
TUPOL05   use link to see paper's listing under its alternate paper code  
 
  • F. Naito, K. Takata
    KEK, Ibaraki, Japan
  • H. Ao, K. Hasegawa, K. Hirano, T. Morishita, N. Ouchi
    JAEA/J-PARC, Tokai-mura, Japan
  
  J-PARC has installed the Annular-ring Coupled Structure (ACS) linac to increase the beam energy up to 400 MeV. One ACS module is composed of two accelerating tanks which are coupled by the bridge cavity. The bridge cavity simplifies the handling of the multi-tank system. While it is possible to feed the RF power into the each tanks directly with the power divider and the phase shifter instead of the bridge cavity. The rf properties of the ACS linac with the direct rf-power supply system has been measured by using the low power model made of aluminum. The measured results are described in the paper.  
slides icon Slides TUPP073 [5.042 MB]  
 
TUPP074
 Study on Fabrication of Superconducting RF 9-cell Cavity for ILC at KEK.  
 
  • T. Saeki, Y. Ajima, K. Enami, H. Hayano, H. Inoue, E. Kako, S. Kato, S. Koike, T. Kubo, S. Noguchi, M. Satoh, M. Sawabe, T. Shishido, A. Terashima, N. Toge, K. Ueno, K. Umemori, K. Watanabe, Y. Watanabe, S. Yamaguchi, A. Yamamoto, Y. Yamamoto, M. Yamanaka, K. Yokoya
    KEK, Ibaraki, Japan
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  • N. Kawabata, H. Nakamura, K. Nohara, M. Shinohara
    SPS, Funabashi-shi, Japan
  • F. Yasuda
    The University of Tokyo, Institute of Physics, Tokyo, Japan
  
  We had constructed the Cavity Fabrication Facility (CFF) for the fabrication of superconducting RF cavity at KEK from 2009 to 2011. In the facility, we installed a deep-drawing machine, a half-cup trimming machine, an electron-beam welding machine, and a chemical etching room in one place. We started the study on the fabrication of 9-cell cavity for International Linear Collier (ILC) from 2009 using this facility. The study is focusing on the cost reduction with keeping high performance of cavity, and the goal is the establishment of mass-production procedure for ILC. We finished the fabrication of two 9-cell cavities by using tools, machines, and equipment of this facility. This article reports the current status of the studies on fabrication of cavity, including the results of vertical tests for the 9-cell cavities which were fabricated in this facillity.  
 
TUPP075 The First Beam Recirculation and Beam Tuning in the Compact ERL at KEK 599
TUPOL01   use link to see paper's listing under its alternate paper code  
 
  • S. Sakanaka, M. Adachi, S. Adachi, M. Akemoto, D.A. Arakawa, S. Asaoka, 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. Jin, E. Kako, Y. Kamiya, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondou, O.A. Konstantinova, 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, M. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, T. Takenaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
    KEK, Ibaraki, Japan
  • E. Cenni
    Sokendai, Ibaraki, Japan
  • R. Hajima, S. Matsuba, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
    JAEA, Ibaraki-ken, Japan
  • J.G. Hwang
    KNU, Deagu, Republic of Korea
  • M. Kuriki, Y. Seimiya
    HU/AdSM, Higashi-Hiroshima, Japan
  • A. Valloni
    CERN, Geneva, Switzerland
  
  Superconducting(SC)-linac-based light sources, which can produce ultra-brilliant photon beams in CW operation, are attracting worldwide attention. In KEK, we have been conducting R&D efforts towards the energy-recovery-linac(ERL)-based light source* since 2006. To demonstrate the key technologies for the ERL, we constructed the Compact ERL (cERL)** from 2009 to 2013. In the cERL, high-brightness CW electron beams are produced using a 500-kV photocathode DC gun. The beams are accelerated using SC cavities, transported through a recirculation loop, decelerated in the SC cavities, and dumped. In the February of 2014, we succeeded in accelerating and recirculating the CW beams of 4.5 micro-amperes in the cERL; the beams were successfully transported from the gun to the beam dump under energy recovery operation in the main linac. Then, precise tuning of beam optics and diagnostics of beam properties are under way. We report our experience on the beam commissioning, as well as the results of initial measurements of beam properties.
* N. Nakamura, IPAC2012, TUXB02.
** S. Sakanaka et al., IPAC2013, WEPWA015. 		 
 
TUPP076
 New Electro-Polishing (EP) Facility at KEK for mass-production study in collaboration with industries.  
 
  • M. Sawabe.
    KEK, Ibaraki, Japan
  
  The construction of the new SRF facility next to the KEK-STF facility has started from 2014 for the mass-production study of SRF accelerators in collaboration with industries. The new building for this facility has the dimension of 80 m x 30 m, and the plan is to install clean-room for cavity-string assembly, cryomodule-assembly facility, cryogenic system, vertical test facility, cryomodule test facility, input coupler process facility, cavity Electro-Polishing (EP) facility, and control-room/office-rooms in it. The purpose of this new SRF facility is to establish a close collaboration between SRF researchers and industries in order to prepare for the upcoming large-scale future SRF project, like ILC. This article reports the status of new Electro-Polishing (EP) facility in this new SRF building at KEK. The EP facility enables Vertical Electro-Polishing (VEP) and High Pressure Rinse of 9-cell cavity, which might realize the mass-production of cavity preparation in low cost. Details of these VEP and HPR system will be presented.  
 
TUPP077 High Precision Manufacturing for LINAC's 603
 
  • F.M. Mirapeix, J. Añel
    HTS, Mendaro, Spain
  • J. Amores, J. Presa, A. Urzainki
    DMP, Mendaro, Spain
  
  A big effort in R&D focused to the LINAC devices together with the know-how already deployed through emblematic projects places DMP in the state of the art of the extreme precision mechanics. This mechanic culture makes of DMP a natural partner in early stages of design or driver of a comprehensive solution, optimizing industrial risks, quality and due date. Surface roughness below 1 nanometer, figure errors better than 50 nanometers in OFE copper enhances lifetime and performance of many devices for LINAC's. Research in joining techniques and combining several alternative technologies to traditional machining improves figure stability and makes complex cooling systems possible.  
 
TUPP078 High Gain FEL with a Micro-bunch Structured Beam by the Transverse-Longitudinal Phase Space Rotation 607
 
  • M. Kuriki, Y. Seimiya
    HU/AdSM, Higashi-Hiroshima, Japan
  • H. Hayano, K. Ohmi
    KEK, Ibaraki, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • R. Kato
    ISIR, Osaka, Japan
  
  FEL is one of the ideal radiation source over the wide range of wavelength region with a high brightness and a high coherence. Many methods to improve FEL gain has been proposed by introducing an active modulation on the bunch charge distribution. The transverse-longitudinal phase-space rotation is one of the promising method to realize the density modulation as the micro-bunch structure. Initially, a beam density modulation in the transverse direction made by a mechanical slit, is properly transformed into the density modulation in the longitudinal direction by the phase-space rotation. That results the longitudinal micro-bunch structure. The micro-bunch structure made with this method has a large tunability by changing the slit geometry, the beam line design, and the beam dynamics tuning. A compact FEL facility based on this method is proposed.  
poster icon Poster TUPP078 [0.594 MB]  
 
TUPP080 Commissioning of the MAX 700 MHz Test Stand 610
 
  • J.-L. Biarrotte, F. Chatelet, M. El Yakoubi, N. Gandolfo, C. Joly, J. Lesrel, H. Saugnac
    IPN, Orsay, France
  • A. Bosotti, R. Paparella, P. Pierini
    INFN/LASA, Segrate (MI), Italy
  • F. Bouly
    LPSC, Grenoble Cedex, France
  • I. Martin-Hoyo
    ADEX, Madrid, Spain
  
  The MYRRHA project aims at the construction of an Accelerator Driven System demonstrator. The criticality will be sustained by an external spallation neutron flux produced thanks to a 600 MeV high intensity proton beam. This beam will be delivered by a superconducting linac which must fulfil very stringent reliability requirements. Under the MAX (MYRRHA Accelerator eXperiment) program, which aims at pursuing the R&D activities on the ADS-type accelerator, a 700 MHz Cryomodule was developed. The main goal of this test stand is to dispose of a facility to carry out “real scale” reliability oriented studies on a RF Superconducting cavity of the high-energy linac section. This module holds 5-cells elliptical cavity equipped with its blade cold tuning system and its coaxial power coupler. The experimental work undertaken at IPN Orsay, has allowed to fully qualify the module in machine configuration (high RF power, at 2K), including assessment of the tuning system and measurement of microphonics spectrums. During this study the dynamic behavior of the fast tuning system of the cavity was also measured. We review here the obtained results and lessons learnt by operating this module.  
 
TUPP082 The MYRRHA Spoke Cryomodule Design 613
 
  • H. Saugnac, J.-L. Biarrotte, S. Blivet, P. Duchesne, N. Gandolfo, J. Lesrel, G. Olry, E. Rampnoux, D. Reynet
    IPN, Orsay, France
  
  In the framework of the MAX project, dedicated to the detailed study of the MYRRHA facility LINAC, the engineering study of the ‘Spoke’ cavities cryomodule, situated in the low energy superconducting section, has been achieved. The beam optics, highly constrained by strong reliability requirements, leads to a modular cryomodule composed of two β=0.37, 352 MHz, single bar ‘Spoke’ cavity cooled at 2K. The power coupler design, not studied in detail under the MAX project, is directly taken from a 20 kW continuous wave 352 MHz coupler designed and successfully tested in the framework of the previous EUROTRANS and EURISOL projects. The cold tuning system is identical to the one designed for the ESS ‘Spoke’ cavities. We present in this paper, the RF, the mechanical and the thermal design of the complete cryomodule as well as the optimization and simulations of its individual components (Cavity, Cryostat, Tuning System…).  
 
TUPP083 Design and Analysis of Slow Tuner in the Superconducting Cavity of RISP 616
 
  • M.O. Hyun, H.C. Jung, H.J. Kim
    IBS, Daejeon, Republic of Korea
  
  Funding: This work was supported by the Rare Isotope Science Project of Institute of Basic Science funded by the Ministry of Science, ICT and Future Planning and National Research Foundation.
Superconducting cavity is one of the most complex systems from the view of mechanical engineering, which is installed and operated in the superconducting linear accelerator. In order to operate SC cavity properly and precisely, superconducting cavity needs many sub-systems, including power coupler for applying RF power inside cavity, and liquid helium jacket for cooling cavity until reaching to the superconducting conditions. And, also cavity needs frequency tuning system for adjusting operating frequency when RF frequency of cavity is changed with outer disturbances such as liquid helium fluctuation, mechanical deformation due to vacuum condition of cavity. Generally, this tuning system is called as a tuner. There are two types of tuner, one is slow tuner which operates with motor, and the other is fast tuner which operates with piezo-electric actuator. This paper describes about design process and analysis results about slow tuner. 		 
 
TUPP084 Surface Treatment Facilities for SCRF Cavities at RISP 619
 
  • J. Joo, D. Jeon, M.J. Joung, Y. Jung, H.J. Kim, M. Lee
    IBS, Daejeon, Republic of Korea
  
  Rare Isotope Science Project is engaged in the fabrication of four types of superconducting RF cavities. The surface treatment is one of the important processes of superconducting RF cavity fabrication. New superconducting RF cavity processing systems have been designed and developed for the etching of niobium in buffered chemical polish at RISP. The safety precautions used in protecting the operator from the acids used in the etchant and from the fumes given of during the process are discussed. All of the new hardware will be located in RISP Munji Superconducting Cavity Test Facility.  
 
TUPP085 RAON Cryomodule Design for QWR, HWR, SSR1 and SSR2 622
 
  • W.K. Kim, H. Kim, H.J. Kim, Y. Kim, M. Lee, G.-T. Park
    IBS, Daejeon, Republic of Korea
  
  The accelerator called RAON which will be built in Korea has four kinds of superconducting cavities such as QWR, HWR, SSR1 and SSR2, operating at 2 K and 4.5 K [1]. The current status of design for the QWR, HWR, SSR1 and SSR2 cryomodules are reported. The issues included in the paper are thermal and structural design results of the components such as supports and thermal shield in the cryomodules. The cryomodule hosts the superconducting cavities in high vacuum and thermally insulated environment in order to maintain the operating temperature of superconducting cavities. It also keeps the cavities in a good alignment to the beam line. It has an interface for supplying RF power to cavities between cold and warm components. The whole configuration of the integrated system is also presented. This paper presents the detailed design of the cryomodule.  
 
TUPP086 RAON Superconducting Radio Frequency Test Facility Construction 625
 
  • H. Kim, D. Jeon, Y.W. Jo, Y. Jung, S.A. Kim, W.K. Kim, S.J. Lee, S.W. Nam, G.-T. Park, J.H. Shin
    IBS, Daejeon, Republic of Korea
  
  Superconducting Radio Frequency (SRF) test facility for RAON is under construction process. It consists of cryogenic system, clean room for cavity process and assembles vertical test, horizontal test, and the radiation shield. The cryoplant has 330 W (4.5 K equivalent) which supplies 4.5K supercritical helium to the cavity test and cryomodule test bench. Clean rooms are for cavity process and assemble whose class is from 10 to 10000. The layout for the vertical and horizontal test bench is shown and the radiation shield for the test bench is shown to reduce X-ray coming from cavity. To estimate the thickness of concrete, radiation simulation is performed.  
 
TUPP088 The Fabrication of the β=0.12 HWR at RISP 628
 
  • G.-T. Park, H.J. Cha, Y. Jung, H. Kim, W.K. Kim
    IBS, Daejeon, Republic of Korea
  
  At RISP, the superconducting cavities have been developed to construct RAON, the heavy ion accelerator. Among the cavities, the fabrication of the QWR (Quarter wave resonator) and the HWR (Half wave resonator)are complete. The detailed fabrication processes including material inspection, forming, the electron beam welding, and the clamp up test are described.  
 
TUPP089 Tuning and Field Stabilization of the CERN Linac4 Drift Tube Linac 631
TUPOL09   use link to see paper's listing under its alternate paper code  
SUPG018   use link to see paper's listing under its alternate paper code  
 
  • M.R. Khalvati
    IPM, Tehran, Iran
  • S. Ramberger
    CERN, Geneva, Switzerland
  
  The Drift Tube Linac (DTL) for the new linear accelerator Linac4 at CERN will accelerate H–beams of up to 40 mA average pulse current from 3 to 50 MeV. The structure consists of three cavities. The first cavity (Tank1) is a 3.9 m long tank containing 38 drift tubes, 10 fixed tuners, 2 movable tuners and 12 post-couplers, operating at a frequency of 352.2 MHz and an average accelerating field of 3.1 MV/m. This paper reports on the results and procedures used for the low–power tuning, stabilization and power coupler tuning carried out on the first Linac4 DTL tank. The upgrade of the bead pull measurement system and twists to the well-known tilt sensitivity technique are discussed.  
 
TUPP090 Spatially Periodic RF Quadrupole LINAC 634
TUPOL06   use link to see paper's listing under its alternate paper code  
SUPG013   use link to see paper's listing under its alternate paper code  
 
  • A.S. Plastun, A. Kolomiets
    ITEP, Moscow, Russia
  
  Spatially-periodic RF quadrupole structure is proposed as second section of front end of ion linac. It consists of conventional drift tubes and RF quadrupoles. Quadrupoles are 4-vane segments with nonzero electric potential on the longitudinal axis. Thus the accelerating electric field is formed between drift tubes and RF quadrupoles. Moreover accelerating field can be provided even inside the RF quadrupoles. It allows building structures with different focusing lattices and provides high energy gain rate.  
poster icon Poster TUPP090 [7.706 MB]  
 
TUPP091 3 BPM Study at PAL ITF 637
 
  • M. Žnidarčič
    I-Tech, Solkan, Slovenia
  • C. Kim, S.J. Lee
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  Pohang Accelerator Laboratory (PAL) is building the 4th generation X-ray free electron laser (XFEL) machine. To examine the efficiency of various diagnostic devices an injector test facility (ITF) was constructed. The last part of the ITF is dedicated for evaluation of beam position measurement devices. A “3-BPM-study” was done with 3 Libera Single Pass E BPM modules that were connected to the 3 equidistantly positioned stripline sensors. The aim of the test was to measure the performances of the Libera Single Pass E devices with beam conditions similar to the real pal XFEL machine.  
 
TUPP092 Developmental and Operational Aspects of Nb QWR Based Heavy Ion LINAC System at IUAC Delhi 640
 
  • S. Ghosh, R. Ahuja, J. Antony, S. Babu, J. Chacko, G.K. Chaudhari, A. Chaudhary, T.S. Datta, R.N. Dutt, R. Joshi, D. Kanjilal, S. Kar, J. Karmakar, M. Kumar, R. Kumar, D.S. Mathuria, K.K. Mistri, A. Pandey, P. Patra, P.N. Potukuchi, A. Rai, J. Sacharias, B.K. Sahu, A. Sarkar, S.S.K. Sonti, S. K. Suman
    IUAC, New Delhi, India
  • A. Roy
    VECC, Kolkata, India
  
  The superconducting linac of IUAC consists of five cryostats containing 27 niobium quarter wave resonators. The prototype and the first 12 resonators were fabricated in collaboration with Argonne National Laboratory. The fabrication of the remaining resonators were carried out using in-house facilities available at IUAC. During the initial period of linac operations, problems were faced to generate higher accelerating fields in the resonators inside the linac cryostat and to reproduce the high fields at the time of beam acceleration. With systemetic efforts, all the major problems are solved and the complete linac is now operational. Since last few years, energized ion beams from linac are being delivered routinely for scheduled experiments. Among the major developmental works related to the linac operation, the vibrational damping mechansim by SS-balls, use of piezo actuator as mechanical tuner and the calculation of optimum phase focussing to control the time width of the beam bunches are noteworthy. Other two developments e.g. automatic phase locking of the resonators and auto beam tuning of the complete linac will be tested during the next beam acceleration.  
 
TUPP093 The Couplers for the IFMIF-EVEDA RFQ High Power Test Stand at LNL: Design, Construction and Operation 643
 
  • E. Fagotti, L. Antoniazzi, M.G. Giacchini, F. Grespan, M. Montis, A. Palmieri, A. Pisent, C. R. Roncolato
    INFN/LNL, Legnaro (PD), Italy
  
  In order to assess the critical aspects of the IFMIF-EVEDA RFQ construction procedure and operation, it was decided to perform a High Power Test of a subset of the RFQ consisting in its last 550 mm three modules (out of 18) plus a Prototype Module, 390 mm long, used as RF plug. These modules are going to be tested at full power in CW of INFN LNL Labs, in the so-called RFQ High Power Test Stand. For such a purpose, a RF tube-based amplifier capable of 220 kW CW output power at the operational frequency of 175 MHz was purchased from an Italian company. A critical component of this test is the RF power coupler. Therefore INFN-LNL developed a design of two identical water-cooled loop antenna couplers, built with OFE copper and vacuum sealed with a commercially available 6”1/8 Alumina planar window. These couplers were tested separately on an aluminium coupling cavity. In particular one of them acts as a power feeder, while the other one, connected with a 200 kW water-cooled load, acts as a receiver. In this paper, the main aspects of the design, construction and tests performed on the couplers and coupling cavity will be described.  
 
TUPP094 Recent Progress of Beam Commissioning at J-PARC Linac 646
 
  • T. Maruta
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • K. Futatsukawa, T. Miyao
    KEK, Ibaraki, Japan
  • M. Ikegami
    FRIB, East Lansing, Michigan, USA
  • Y. Liu
    KEK/JAEA, Ibaraki-Ken, Japan
  • A. Miura, H. Sako
    JAEA/J-PARC, Tokai-mura, Japan
  
  We installed Annular-type Coupled Structure (ACS) linac in year 2013 in present linac downstream to extend the beam energy from 181 to 400 MeV. The beam commissioning had been conducted for one month in last December to January, and then we successfully extract 400 MeV beam. Whereas, we stably operate the linac at peak current of 15 mA, which is equivalent to 300 kW at the extraction of 3 GeV RCS, we observe unexpected residual radiations in ACS section. In this presentation, we review the recent progress in beam commissioning and beam loss study.  
 
TUPP095 High-Power Test Results of the RFQ III in J-PARC Linac 649
 
  • T. Morishita, K. Hasegawa, K. Hirano, Y. Kondo, H. Oguri, S. Yamazaki
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • T. Hori
    JAEA, Ibaraki-ken, Japan
  • F. Naito, T. Sugimura, A. Takagi
    KEK, Ibaraki, Japan
  
  The J-PARC accelerator comprises an injector linac, a 3-GeV Rapid-Cycling Synchrotron and a 50-GeV Main Ring. The beam energy of the linac has been upgraded from 181MeV to 400MeV in 2013. For the beam current upgrade, the new frontend (RF ion source, RFQ, chopping system) installation is scheduled in summer 2014 for 1MW operation at RCS. The RFQ III, which is designed for 50mA beam acceleration from 0.05MeV to 3MeV, has been fabricated and the high-power test has started at April 2013 at the test station in the J-PARC. The test station consists of the ion source, the LEBT, the RFQ, and the diagnostics devices. The nominal RF power and RF duty of the RFQ III are 380kW and 3%(0.6ms and 50Hz), respectively. The high-power conditioning reached to the 120% of the nominal power with 1.5% (0.6ms, 25Hz) RF duty within 24 hours. Then, we performed the beam operation at the test station and measured beam parameters after the RFQ III. The results of the high-power conditioning and the stability of the RFQ operation with beam will be discussed.  
 
TUPP096 LUE-200 Linac. Status & Development 653
 
  • A.P. Sumbaev, A.S. Kayukov, V. Kobets, V. Minashkin, V.G. Pyataev, V.A. Shvets
    JINR, Dubna, Moscow Region, Russia
  • V. Shabratov
    JINR/VBLHEP, Moscow, Russia
  • V.N. Shvetsov
    JINR/FLNP, Moscow Region, Russia
  
  The general scheme and current status of an electron linear accelerator with an S-band travelling wave (f = 2856 MHz) accelerating structure – a driver for a pulsed neutron source (IREN) at the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research - are presented. The parameters of the accelerating system and the measured parameters of the electron beam – pulse-beam current, duration of the current pulse, repetition rate, electron-energy spectrum, and loading characteristics of the accelerating structure - are given. The beginning of the implementation of the project of the second stage of the IREN facility, which forms the basis for the development of the accelerator aimed at increasing its beam power, is reported. Technical solutions underlying the modernization of the accelerator’s electrophysical systems are discussed: accelerating system, RF power supplies,and modulators.  
 
TUPP097 100-MeV Proton Beam Phase Measurement by Using Stripline BPM 656
 
  • H.S. Kim, Y.-S. Cho, H.-J. Kwon
    KAERI, Daejon, Republic of Korea
  
  Funding: This work is supported by Ministry of Science, ICT & Future Planning of the Korean Government.
In Korea Multipurpose Accelerator Complex (KOMAC), a 100-MeV proton linac, which is composed of a proton injector based on the microwave ion source, 3-MeV RFQ with a four-vane type and 100-MeV DTL with electromagnetic quadrupoles has been developed and currently provides the proton beam to users for various applications. To increase the beam power up to the design value, several improvements are required including the fine adjustment of the RF set-point during the operation. A stripline BPM is used for the beam phase measurement, where the pickup signals from four electrodes are combined by using the RF combiner, then mixed with 300 MHz LO reference signal resulting in 50 MHz IF signal which is processed by digital IQ demodulation method. In this paper, the details of the beam phase measurement setup and results will be presented. 		 
 
TUPP100 Operation Of The Versatile Accelerator Driving the Low Power ADS GUINEVERE at SCK•CEN 659
TUPOL07   use link to see paper's listing under its alternate paper code  
 
  • M.A. Baylac, A. Billebaud, P. Boge, D. Bondoux, J. Bouvier, S. Chabod, G. Dargaud, E. Froidefond, E. Labussière, R. Micoud, S. Rey
    LPSC, Grenoble Cedex, France
  • A. Kochetkov, J. Mertens, F. Van Gestel, C. Van Grieken, B. Van Houdt, G. Vittiglio
    SCK•CEN, Mol, Belgium
  • F.R. Lecolley, J.L. Lecouey, G. Lehaut, N. Marie-Nourry
    CNRS/IN2P3/LPC CAEN, Caen, France
  
  GUINEVERE provides a low power accelerator driven system (ADS) to investigate on-line reactivity monitoring and operational procedures of an ADS. It consists of a versatile neutron source, GENEPI-3C, driving the fast sub-critical core, VENUS-F, in SCK•CEN (Belgium). GENEPI-3C is an electrostatic accelerator generating 14 MeV neutrons by bombarding a 250 keV deuteron beam onto a tritium target located within the reactor core. This accelerator produces alternatively continuous beam (up to 1 mA DC), possibly chopped with fast and adjustable interruptions, or short and intense deuteron bunches (~25 mA peak, 1 μs). This paper presents the facility and assesses the 2 years of coupled operation of the accelerator to the reactor.  
slides icon Slides TUPP100 [0.969 MB]  
 
TUPP101 Vertical Electro-Polishing of Nb Single-Cell Cavity Using Cathode with Variable-Geometry Wings and Its Results of Vertical Test 662
 
  • K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • P. Carbonnier, F. Éozénou, C. Servouin
    CEA/DSM/IRFU, France
  • H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
    KEK, Ibaraki, Japan
  • K. Ishimi
    MGI, Chiba, Japan
  • C. Madec, L. Maurice
    CEA/IRFU, Gif-sur-Yvette, France
  
  Marui Galvanizing Co. Ltd. has been studying Vertical Electro-Polishing (VEP) on Nb superconducting accelerator cavity with the goal of mass-production and cost-reduction of Electro-Polishing (EP) process in collaboration with KEK and CEA Saclay. And we invented variable-geometry wings cathode for VEP process to get uniform distributions of both electric current and EP solution flow. Using this cathode, we performed various tests of VEP with Nb single-cell cavities. In this article, we will report the results of vertical test of Nb single-cell cavity which is VEP’ed by cathode with variable-geometry wings.  
 
TUPP102
 Compact Accelerator-driven Neutron Sources in Japan  
 
  • M. Kitaguchi, K. Hirota, Y. Kiyanagi, H.M. Shimizu
    Nagoya University, Nagoya, Japan
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  
  In Japan compact accelerator-driven neutron sources were built under activity of JCANS (Japan Collaboration on Accelerator-driven Neutron Sources). Now, there are 4 accelerator-driven neutron sources used for neutron science; HUNS (Hokkaido University Neutron Source), KUANS (Kyoto University Accelerator-driven Neutron Source), RANS (RIKEN Accelerator-driven Neutron Source), and NUANS (Nagoya University Accelerator-driven Neutron Source). HUNS has been used for neutron science for a long time and still actively used for imaging, small angle scattering, device development and so on. KUANS has been proved to be useful for imaging and new development is underway for reflectometry. RANS is mainly devoted to industrial ap plications and used for imaging now. NUANS is now under construction for test facility for cancer therapy (BNCT). These activity is also supported by UCANS (Union of Compact Accelerator-driven Neutron Sources). Here, we present our overall activity of JCANS.  
 
TUPP103 The Beam Envelope Control in SC Linac for the Proton Radiotherapy 665
SUPG014   use link to see paper's listing under its alternate paper code  
 
  • A.V. Samoshin, I.A. Ashanin, S.M. Polozov
    MEPhI, Moscow, Russia
  
  Proton cancer therapy is conventionally based on normal conducting synchrotrons and cyclotrons. The high electrical power consumption and especial devices necessary to energy variation are main problems of such facilities. Superconducting linacs based on short identical independently phased cavities have a seriously progress and it's development allow to propose their using for medical application. High accelerating gradient and small capacity losses nearly 10-4 Vt/m are main advantages in advance of normal conducting facilities, the energy variation can be realized by means of RF field amplitude and phase variation in a number of cavities. Besides linac structures are lack of unwieldy magnetic system, simplicity of input and output of particles and high current densities. The parameters choose and the optimization for SC linac structure with energy up to 240 MeV and envelope control will discuss in this paper. The simulation was done using BEAMDULAC-SCL code*. The study of beam dynamics will direct to realize the energy variation in range 150-240 MeV with beam quality preservation.
* A.V. Samoshin. Proc. of LINAC2012, Tel-Aviv, Israel, TUPB069, p. 630 - 632 		 
 
TUPP105 Storage Ring as a Linac Beam Monitor – Its Operation and Contribution to the Stable Top-up Injection 668
 
  • Y. Shoji
    LASTI, Hyogo, Japan
  • T. Asaka, H. Dewa, H. Hanaki, T. Kobayashi, Y. Minagawa, A. Mizuno, T. Shinomoto, S. Suzuki, Y. Takemura, T. Taniuchi, K. Yanagida
    JASRI/SPring-8, Hyogo-ken, Japan
  
  We have used the electron storage ring, NewSUBARU, as a beam monitor of the SPring-8 linac. The time and transverse profiles of the injected linac beam are recorded in a frame of a dual-sweep streak camera. A measurements through synchrotron or betatron oscillation in the ring gives multi-dimensional beam structure. The system functions as a final check of the linac beam. It gives the time profile and energy profile or transverse emittance, which includes Twiss parameters. It measures parameters of one linac bunch in a long macro pulse. A shot-by-shot measurement gives beam fluctuations. We report how we use the system and its contribution to the stable top-up operation. The beam loading effect on the bunch energy was obtained by bunch-by-bunch energy profile measurements. It confirmed the optimization of the ECS (Energy Compression System) parameters. The single shot bunch-by-bunch vertical emittance measurement proved the difference between the front bunch and the following bunches. The same measurement showed a timing jitter of the electron gun pulse although the rf synchronization was perfect. This jittering had made the injection efficiency unstable.  
 
TUPP106 RF Characteristics of 20K Cryogenic 2.6-cell Photocathode RF-gun Test Cavity 671
 
  • T. Sakai, M. Inagaki, K. Nakao, K. Nogami, T. Tanaka
    LEBRA, Funabashi, Japan
  • M.K. Fukuda, T. Takatomi, J. Urakawa, M. Yoshida
    KEK, Ibaraki, Japan
  • T.S. Shintomi
    Nihon University, Tokyo, Japan
  
  Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
The cryogenic C-band photocathode RF gun operating at 20K is under development at LEBRA in Nihon University. The RF gun is of the BNL-type 2.6-cell pillbox cavity with the resonant frequency of 5712 MHz. The 6N8 high purity OFC copper is used as the cavity material. From the theoretical evaluation of the anomalous skin effect, the quality factor Q of the cavity has been expected to be about 60000. Considering a low cooling capacity of the cryocooler system, initial operation of the RF gun is assumed at a duty factor of 0.01 %. The cavity basic design and the beam bunching simulation were carried out using SUPERFISH and General Particle Tracer (GPT). Machining of the cavity was carried out in KEK. The RF characteristics measured at room temperature and 20K will be reported. 		 
 
TUPP108 HOM and Impedance Study of RF Separators for LCLS II 674
SUPG022   use link to see paper's listing under its alternate paper code  
 
  • S.U. De Silva, J.R. Delayen, B.R.P. Gamage, G.A. Krafft, T. Satogata
    ODU, Norfolk, Virginia, USA
  • R.G. Olave
    Old Dominion University, Norfolk, Virginia, USA
  
  The LCLS-II upgrade requires an rf spreader system to guide bunches into a switchyard delivering beam to two undulators and the primary beam dump. The beam pattern therefore needs a 3-way beam spreader. An rf deflecting cavity concept was proposed that includes both superconducting and normal conducting options. We characterize the higher order modes (HOM) of these rf separator cavities and evaluate beam dynamics effects due to potential HOM excitation. This study includes both short term wake and multi-bunch effects.  
poster icon Poster TUPP108 [1.032 MB]  
 
TUPP109 Cryogenic Testing of High-Velocity Spoke Cavities 677
SUPG023   use link to see paper's listing under its alternate paper code  
 
  • C.S. Hopper, J.R. Delayen, H. Park
    ODU, Norfolk, Virginia, USA
  • J.R. Delayen, H. Park
    JLab, Newport News, Virginia, USA
  
  Spoke-loaded cavities are being investigated for the high-velocity regime. The relative compactness at low-frequency makes them attractive for applications requiring, or benefiting from, 4 K operation. Additionally, the large velocity acceptance makes them good candidates for the acceleration of high-velocity protons and ions. Here we present the results of cryogenic testing of a 325 MHz, β0 = 0.82 single-spoke cavity and a 500 MHz, β0 = 1 double-spoke cavity.  
 
TUPP110 Quasi Nonlinear Plasma Wakefield Acceleration Experiments 680
SUPG031   use link to see paper's listing under its alternate paper code  
 
  • S.K. Barber, G. Andonian, B.D. O'Shea, J.B. Rosenzweig, Y. Sakai, O. Williams
    UCLA, Los Angeles, USA
  • M. Ferrario
    INFN/LNF, Frascati (Roma), Italy
  • P. Muggli
    MPI, Muenchen, Germany
  
  It is generally agreed that the best way forward for beam driven plasma wakefield acceleration (PWFA) is in the nonlinear or blowout regime. In this regime the expulsion of the plasma electrons from the beam occupied region produces a linear transverse focusing effect and position independent longitudinal accelerating fields, which can, in principle, produce high quality beams accelerated over many meters. However, certain aspects of a linear plasma response can be advantageous, such as the possibility for resonant excitation of wakefields through the use of pulse trains. Exploiting advantages of both linear and nonlinear PWFA may be achievable through the use of low emittance and tightly focused beams with relatively small charge. In this case the beam density can be greater than that of the ambient plasma while simultaneously having a smaller total charge than the plasma electrons contained in a cubic plasma skin depth allowing for blowout in the region of the beam while simultaneously maintaining a quasi linear response in the bulk plasma. Recent experiments at BNL have been aimed at probing various salient aspects of this regime and are presented here.  
 
TUPP111 SwissFEL C-band LLRF Prototype System 683
 
  • A. Hauff, M. Broennimann, I. Brunnenkant, A. Dietrich, Z. Geng, F. Gärtner, M. Jurcevic, R. Kalt, S. Mair, A. Řežaeizadeh, L. Schebacher, T. Schilcher, W. Sturzenegger
    PSI, Villigen PSI, Switzerland
  
  SwissFEL is driven by more than 30 RF stations at different frequencies (S-, C-, X-band). To control the RF a new, in-house developed digital Low Level RF (LLRF) system measures up to 24 RF signals per station and performs a pulse-to-pulse feedback at a repetition rate of 100 Hz. The RF signals are down-converted to a common intermediate frequency. The state-of-the-art digital processing units are integrated into the PSI’s EPICS controls environment. Emphasis has been put on modularity of the system to provide a well-defined path for upgrades. Thus the RF front ends are separated from the digital processing units with their FMC standard interfaces for ADCs and DACs. A first prototype of the LLRF system consisting of the digital back end together with a C-band RF front end was installed in the SwissFEL C-band test facility. In this report the performance of the prototype system has been compared with the LLRF system requirements for SwissFEL. The critical parameters are high intra-pulse phase and amplitude resolutions, good channel-to-channel isolations, very low phase to amplitude modulation and a negligible temperature drift.  
 
TUPP112 Study of a C-Band TW Electron Gun for SwissFEL 686
SUPG032   use link to see paper's listing under its alternate paper code  
 
  • M. Schaer, A. Citterio, P. Craievich, L. Stingelin, R. Zennaro
    PSI, Villigen PSI, Switzerland
  
  For a future upgrade of the SwissFEL facility, the replacement of the S-band standing wave electron gun by a C-band standing wave, or traveling wave gun is investigated. The full model of the C-band TW gun is calculated with HFSS and is characterized by an almost vanishing group velocity in the first cell to increase the field at the cathode. ASTRA simulations predict that in the case of the C-band SW gun, a two times higher peak current of ~ 40 A can be generated while still preserving the low slice emittance of ~ 0.2 um at 200 pC, due to the higher electric field on cathode and improved magnetic focusing. This would help to halve the overall beam compression factor, relax the phase stability requirement of S- and X-band systems operated off-crest for compression and decrease the gain curve in theμbunch instability. Compared to the SW gun, a TW gun provides a more homogeneous acceleration and does not require any circulator. In this study, the preliminary RF design and beam performance of a C-band TW gun is presented and compared to a pure C-band SW gun presently under design at Paul Scherrer Institut and to the operating S-band SW gun.  
 
TUPP113 High RF Power Test of Coupled RFQ-SFRFQ Cavity 689
SUPG034   use link to see paper's listing under its alternate paper code  
 
  • W.L. Xia, J.E. Chen, S.L. Gao, F.J. Jia, Y.R. Lu, Z. Wang, J. Zhao, K. Zhu
    PKU, Beijing, People's Republic of China
  
  Funding: This work was supported in part by the National Natural Science Foundation of China under Grant No. 11075008, 11079001 and 11175009.
A new combined accelerator that couples radio frequency quadrupole (RFQ) and separated function radio frequency quadrupole (SFRFQ) in a single cavity has been designed and manufactured. Recently, the performance of the cavity under high RF power was tested with an upgraded RF power source. The inter-vane voltages of both RFQ section and SFRFQ section were measured by using high purity germanium detector and the corresponding measurement system. The measured shunt impedance is about 546.9 kΩ•m, which means the cavity needs 19.5 kW for the designed inter-vane voltage of 65 kV. The results are well consistent with the cavity design. 		 
poster icon Poster TUPP113 [0.764 MB]  
 
TUPP116 Status of the FERMI II RF Gun at Sincrotrone Trieste 692
 
  • L. Faillace, R.B. Agustsson, P. Frigola, A. Verma
    RadiaBeam, Santa Monica, California, USA
  
  Radiabeam Technologies, in collaboration with UCLA, developed a high gradient normal conducting radio frequency (NCRF) 1.6 cell photoinjector system, termed the Fermi Gun II, for the Sincrotrone Trieste (ST) facility. The RF gun has been already in full operation since mid-2013 as the injector for the ST FEL. We report here the current status of the photoinjector system.  
 
TUPP117 Commissioning of Vertical Test Stand Facility for 2 K Testing of Superconducting Cavities at RRCAT 695
 
  • S.C. Joshi, A. Chauhan, P. Fatnani, P.D. Gupta, M.K. Kumar, P.K. Kush, P. Mohania, S. Raghvendra, P. Shrivastava, S.K. Suhane
    RRCAT, Indore (M.P.), India
  
  Raja Ramanna Centre for Advanced Technology (RRCAT) has developed a 2K vertical Test Stand (VTS) facility for characterization of Superconducting RF (SCRF) cavities, under Indian Institution Fermilab Collaboration (IIFC). The VTS facility comprises of a large size liquid helium (LHe) cryostat, cryogenic system, RF power supply, control and data acquisition system and radiation monitoring system. It will facilitate testing of superconducting cavities of different frequencies ranging from 325 MHz low beta to 650 MHz / 1.3 GHz medium and high beta cavities. The helium vessel has a capacity to store up to 2900 litres of liquid Helium. The cryostat is installed inside a vertical pit. It is equipped with facilities for supply of liquid nitrogen and liquid helium and vacuum system for pumping out helium gas to lower the temperature of liquid helium bath down to 1.8 K. A 200 W, 1.3 GHz RF system has been indigenously developed for testing of the SCRF cavities. The VTS facility has now been commissioned and its performance validation has been successfully carried out by benchmarking it with respect to the facility at the Fermilab.  
 
TUPP119 Design Studies for Medium and High beta SCRF Cavities for Indian Spallation Neutron Source 699
 
  • A.R. Jana, V. Kumar
    RRCAT, Indore, India
  
  There is a plan to build a 1 GeV H− linac for the proposed Indian Spallation Neutron Source (ISNS) at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore. The medium and high energy section of the ISNS linac will consist of betag=0.61, as well as betag = 0.9, 650 MHz, 5-cell superconducting radiofrequency (SCRF) cavities, for which detailed electromagnetic design studies have been performed. During our design study, we have evolved a generalized procedure for the optimization of geometrical parameters of multi-cell SCRF cavities. Studies on higher order modes supported by the cavity and its effect on beam dynamics, as well as on heat load to the cavity have been performed, which constitute an important aspect of the design study. Finally, detailed studies on Lorentz Force Detuning (LFD) have been performed, and design of the cavity has been optimized to minimize the effect due to the LFD. The paper discussed the details of the calculations and the studies that have been performed during the design study.  
 
TUPP120 Commissioning of BINP Injection Complex VEPP-5 702
 
  • A.A. Starostenko, A.E. Levichev, D.A. Nikiforov
    BINP SB RAS, Novosibirsk, Russia
  
  New BINP injector complex VEPP-5 consist of S-band linear accelerators (270 and 420MeV), positron converter (at 270 MeV) and damping ring. The injector complex will provide e+/e− particles for the 2 colliders at BINP - VEPP-4M and VEPP-2000. After a long construction period the injector is in its commissioning stage now. Positron rate production of 6·108 positrons/pulse and conversion yield of 0.14/GeV and stored positron beam current of 70mA were already achieved.  
 
TUPP121 Limitations for Acceleration of Intermediate Mass Particles with Traveling Wave Structure 705
 
  • V.V. Paramonov
    RAS/INR, Moscow, Russia
  
  The Disk Loaded Waveguide (DLW) is the mostly used high frequency structure for acceleration of lightweight particles – electrons in the high energy range. DLW parameters are considered for the lower frequency range and lower particle velocity. Physical and technical restrictions for DLW application for the low particles velocity are analyzed. Basing on particularities of acceleration with traveling wave, deep optimization of DLW cells dimensions, the choice of optimal operating phase advance for each DLW section and combination of forward and backward wave modes, it looks possible to create the simple, cost effective acceleration system for intermediate particles acceleration in the moderate velocity range, in some parameters overcoming accelerating system with RF cavities in the standing wave mode.  
 
TUPP122 Roughness Tolerances in the Undulator Vacuum Chamber of LCLS-II 708
 
  • K.L.F. Bane, G.V. Stupakov
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by Department of Energy contract DE–AC02–76SF00515.
In LCLS-II, after acceleration and compression and just before entering the undulator, the beam passes through roughly 2.5 km of 24.5 mm (radius) stainless steel pipe. The bunch that passes through the pipe is extremely short with an rms of 8 um for the nominal 100 pC case. Thus, even though the pipe has a large aperture, the wake that applies is the short-range resistive wall wakefield. It turns out that the wake supplies needed dechirping to the LCLS-II beam before it enters the undulator. The LCLS-II bunch distribution is approximately uniform, and therefore the wake induced voltage is characterized by a rather linear voltage chirp for short bunches. However for bunches longer than 25 um (300 pC at 1 kA) the wake starts to become nonlinear, effectively limiting the maximum charge with which the LCLS-II can operate. In this note we calculate the wake, discuss the confidence in the calculation, and investigate how to improve the induced chirp linearity and/or strength. Finally, we also study the strength and effects of the transverse (dipole) resistive wall wakefield. 		 
 
TUPP123 Design of Novel RF Sources to Reduce the Beam Pace-Charge Effects 712
TUPOL10   use link to see paper's listing under its alternate paper code  
 
  • M. Dal Forno, A. Jensen, R.D. Ruth, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  
  Funding: DOE
Traditional RF sources, such as Klystrons, TWT require a magnet (such as a solenoid) in order to maintain the electron beam focusing, compensating the particle repulsion caused by space charge effects. We designed a novel RF source with an alternative approach that reduces beam space charge problems. This paper shows the design of the device, with a new formulation of the Child’s Law, and the mode-beam stability analysis. The electron beam interaction with the cavity fields has been analyzed by means of particle tracking software in order to evaluate the beam bunching and the beam dynamics. 		 
poster icon Poster TUPP123 [0.172 MB]  
 
TUPP124
 Update on High Power Tests of Single Cell Standing Wave structures at SLAC  
 
  • V.A. Dolgashev, J.R. Lewandowski, S.G. Tantawi, S.P. Weathersby, A.D. Yeremian
    SLAC, Menlo Park, California, USA
  • Y. Higashi
    OIST, Onna-son, Okinawa, Japan
  • B. Spataro
    INFN/LNF, Frascati (Roma), Italy
  
  Funding: This work was supported by the U.S. Department of Energy contract DE-AC02-76SF00515.
We report results of ongoing high power tests of single cell standing wave structures. These tests are part of an experimental and theoretical study of rf breakdown in normal conducting structures at 11.4 GHz. The goal of this study is to determine the accelerating gradient capability of normal-conducting rf powered particle accelerators. The test setup consists of reusable mode-launchers and short test structures powered by SLAC's XL-4 klystron. We have tested structures of different geometries, cell joining techniques, and materials, including copper structures with molybdenum and stainless steel irises. In previous experiments we found that the breakdown rate is correlated more with peak surface pulse heating than with the peak surface electric field. In recent experiments we continue study of hard cooper alloys and manufacturing techniques that avoid heat treatment of the metal. As a result we observed that cooper silver alloys show superior performance in comparison with both hard and heat treated copper. 		 
 
TUPP127 R&D of X-band Accelerating Structure for Compact XFEL at SINAP 715
 
  • W. Fang, Q. Gu, M. Zhang, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  • A.A. Aksoy, Ö. Yavaş
    Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
  • D. Angal-Kalinin, J.A. Clarke
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C.J. Bocchetta, A.I. Wawrzyniak
    Solaris, Kraków, Poland
  • M.J. Boland
    SLSA, Clayton, Australia
  • G. D'Auria, S. Di Mitri, C. Serpico
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • T.J.C. Ekelöf, R.J.M.Y. Ruber, V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  • E.N. Gazis
    National Technical University of Athens, Athens, Greece
  • A. Grudiev, A. Latina, D. Schulte, S. Stapnes, W. Wuensch
    CERN, Geneva, Switzerland
  
  One compact hard X-ray FEL facility is being planned at SINAP, and X-band high gradient accelerating structure is the most competetive scheme for this plan. X-band accelerating structure is designed to switch between 60MV/m and 80MV/m, and carries out 6GeV and 8GeV by 130 meters linac respectively. In this paper, brief layout of compact XFEL will be introduced, and in particular the prototype design of dedicated X-band acceleration RF system is also presented.  
 
TUPP128 ECHO-enabled Tunable Terahertz Radiation Generation with a Laser-modulated Relativistic Electron Beam 719
 
  • D. Huang, Q. Gu, Z. Wang, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  • D. Xiang
    Shanghai Jiao Tong University, Shanghai, People's Republic of China
  
  A new scheme to generate narrow-band tunable Terahertz (THz) radiation using a variant of the echo-enabled harmonic generation is analyzed. We show that by using an energy chirped beam, THz density modulation in the beam phase space can be produced with two lasers having the same wavelength. This removes the need for an optical parametric amplifier system to provide a wavelength-tunable laser to vary the central frequency of the THz radiation. The practical feasibility and applications of this scheme is demonstrated numerically with a start-to-end simulation using the beam parameters at Shanghai Deep Ultraviolet Free-Electron Laser facility (SDUV). The central frequency of the density modulation can be continuously tuned by either varying the chirp of the beam or the momentum compactions of the chicanes. The influence of nonlinear RF chirp and longitudinal space charge effect have also been studied in our article. We also briefly discuss how one may retrieve the beam longitudinal phase space through measurement of the THz density modulation. \end{abstract}  
 
TUPP129
 A measurement and tuning method for traveling wave deflecting structure  
 
  • J.H. Tan, W. Fang, Q. Gu, Z.T. Zhao
    SINAP, Shanghai, People's Republic of China
  • D.C. Tong
    TUB, Beijing, People's Republic of China
  
  For traveling wave accelerating structures, the tuning method assisted by bead pull technique based on non-resonant perturbation field distribution measurement has been widely applied for measure and tuning both constant-impedance and constant-gradient structures. The method is also suitable for deflecting structures, but some key considerations of the field component and of the bead are discussed. The measurement and tuning method will be used on new X-band deflecting cavity at SINAP, and the measurement on S-band traveling wave deflecting cavity is presented at last.  
 
TUPP130 Optimization of Beam Parameters in APF Channel 722
SUPG035   use link to see paper's listing under its alternate paper code  
 
  • V.V. Altsybeyev, D.A. Ovsyannikov
    St. Petersburg State University, St. Petersburg, Russia
  
  A new approach based on mathematical optimization methods to obtain a synchronous phase sequence in APF linacs is suggested. The optimization problem of intensity deuteron beam parameters is discussed. As an example, the results of beam dynamics simulations are presented.  
 
TUPP131
 Beam Dynamics Optimization in Axially Symmetric Electrostatic and Magnetic Fields  
 
  • A.D. Ovsiannikov
    St. Petersburg State University, St. Petersburg, Russia
  
  Funding: This work was supported by Saint-Petersburg State University, project number 9.38.673.2013.
The problem of optimization of charged particle beam dynamics in superposition of an axially symmetric electric and magnetic fields is considered. The complex potential of the electric field is represented as a Cauchy integral of a control function defined on the boundary of the region. Analytical representation of functional variation is found and the optimality conditions are formulated. 		 
 
TUPP133 Optimization of the RF Cavity of the Medical Purpose Electron Linac by Using Genetic Algorithm 726
SUPG004   use link to see paper's listing under its alternate paper code  
 
  • S. Shin, J.-S. Chai
    SKKU, Suwon, Republic of Korea
  
  A compact electron linear accelerator for the medical application has been developing at Sungkyunkwan University. Due to this electron linac is attached on the robot arm or gantry, it should be compact enough to be held by the structure. An X-band technology has been used to meet the requirements for the compact linac. Because the particle accelerator is complex and sensitive machine to design it takes a lot of time to get a good performance accelerator. In this research, a special technique named single-objective genetic algorithm for the optimization process has been applied to achieve a better RF cavity design by changing various geometric parameters.  
 
TUPP134
 The development of electron gun for a S-band Linear accelerator  
 
  • Y.H. Yeon, J.-S. Chai, J.C. Lee, S.H. Lee
    SKKU, Suwon, Republic of Korea
  • B.N. Lee, B.C. Lee
    KAERI, Dae-jeon, Republic of Korea
  
  Diode type electron gun is developed for a S-band linear accelerator which is used for X-ray inspection system. Thermal analysis of the electron gun has been carried out for the optimizing the design of cathode support and heat shield. The simulation of thermal expansion of the cathode support and heat shield structure is done for avoiding electrical breakdown. Performance of the gun assembly, designed and developed with thermal requirements, has been evaluated experimentally  
 
TUPP135 Beam Dynamics Calculations and Magnet Design for Future Measurements of Transverse Beam Break-Up at the S-DALINAC* 729
 
  • F. Hug, M. Arnold, L.E. Jürgensen, T. Kürzeder, N. Pietralla, M. Schilling
    TU Darmstadt, Darmstadt, Germany
  
  Funding: *Work supported by the BMBF through 05K13RDA
The superconducting electron accelerator S-DALINAC at TU Darmstadt produces c.w. electron beams of up to 90 MeV. The S-DALINAC consists of a SC 14-MeV injector linac, a SC main linac and two recirculation paths. Currently a third recirculation is in its final design phase and will be constructed end 2014 in order to achieve an energy of 130 MeV in future. The main linac houses eight 20-cell SRF cavities operated at 3 GHz and 2 K. Due to the occurance of transverse beam break-up, the highest stable beam current obtained so far amounts to 5 μA only, which is below the design beam current of 20 μA but sufficient for the nuclear physics experiments carried out at Darmstadt since 1991. In this work we will present beam-dynamics calculations and newly designed magnets for planned experiments at the S-DALINAC in order to benchmark different strategies of increasing the threshold current for beam break-up. 		 
 
TUPP137 High Power Solid-State Amplifiers. New Developments and Technology Comparison 733
 
  • G.B. Sharkov, A.I. Botyachkova, E.V. Ivanov, N.G. Kalugin, A.A. Krasnov, K.K. Naraianamurtkhi, K.I. Nikolskiy, S.A. Polikhov, I. Řežanov, A.Yu. Smirnov, P. Yazev
    Siemens Research Center, Moscow,, Russia
  • A.I. Botyachkova
    National Research Nuclear University (MEPhI), Moscow, Russia
  
  Funding: Skolkovo Foundation, contract #44 from 2011.11.14
We present a newly developed compact and cost effective SSPA with megawatt range output power and scalable architecture. System components test results are discussed. A comparison of the state-of-the-art vacuum tube and solid-state technologies of RF power amplifiers for scientific accelerators is given.
Solid-state microwave generator, Siemens 		 
 
TUPP138 Analysis of New High-Q0 SRF Cavity Tests by Nitrogen Gas Doping at Jefferson Lab 736
 
  • A.D. Palczewski, R.L. Geng, C.E. Reece
    JLab, Newport News, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
In order to refine systematic understanding and establish confident process control, Jefferson Lab has joined with partners to investigate and thoroughly characterize the dramatically higher Q0 of 1.3 GHz niobium cavities first reported by FNAL in 2013[1]. With partial support from the LCLS-II project, JLab has undertaken a parametric study of nitrogen doping in vacuum furnace at 800 C followed by variable depth surface removal in the 5 - 20 μm range. Q0 above 3×1010 are typical at 2.0 K and 16 MV/m accelerating field. We report observations from the single cell study and current interpretations. In addition to the parametric single cell study, we also report on the ongoing serial testing of six nitrogen-doped 9-cell cavities as baseline prototypes for LCLS-II.
[1] A. Grassellino, et al., Supercon. Sci.and Tech., 2013. 26(10): p. 102001 		 
poster icon Poster TUPP138 [4.214 MB]  
 
TUPP139 Design Studies with DEMIRCI for SPP RFQ 740
 
  • B. Yasatekin, G. Turemen
    Ankara University, Faculty of Sciences, Ankara, Turkey
  • A. Alacakir
    TAEK, Ankara, Turkey
  • G. Unel
    UCI, Irvine, California, USA
  
  To design a Radio Frequency Quadrupole (RFQ) is a onerous job which requires a good understanding of all the main parameters and the relevant calculations. Up to the present there are only a few software packages performing this task in a reliable way. These legacy software, though proven in time, could benefit from the modern software development tools like Object Oriented (OO) programming. In this note, a new RFQ design software, DEMIRCI is introduced. It is written entirely from scratch using C++ and based on CERN's OO ROOT library. It has a user friendly graphical user interface and also a command line interface for batch calculations. It can also interact by file exchange with similar software in the field. After presenting the generic properties of DEMIRCI, its compatibility with similar software packages is discussed based on the results from the reference design parameters of SPP (SNRTC Project Prometheus), a demonstration accelerator at Ankara, Turkey.  
poster icon Poster TUPP139 [11.590 MB]  
 
TUPP140 Observation of >GV/m Decelerating Fields in Dielectric Lined Waveguides 743
THIOB04   use link to see paper's listing under its alternate paper code  
SUPG026   use link to see paper's listing under its alternate paper code  
 
  • B.D. O'Shea, G. Andonian, K.L. Fitzmorris, S. Hakimi, J. Harrison, J.B. Rosenzweig, O. Williams
    UCLA, Los Angeles, California, USA
  • M.J. Hogan, V. Yakimenko
    SLAC, Menlo Park, California, USA
  
  Recent experimental measurements of the energy lost to wakefields in a dielectric lined waveguide are presented. These measurements demonstrate average decelerating gradients on the order of >1 GV/m, for two different structures. The measurements were made at the Facility for Advanced aCcelerator Experimental Tests (FACET) at SLAC National Laboratory using sub-millimeter diameter fifteen-centimeter long quartz fibers of annular cross section. The unique extremely short, high charge, ultra relativistic beam at FACET (200 fs, 3 nC, 20 GeV) allows the use of dielectric wakefield structures of unprecedented size and length. In addition to experimental results, we support conclusions with simulation and theoretical work. This measurement builds on a large body of work previously performed using dielectric wakefield structures in an effort to provide high gradient accelerating structures for tomorrows linear colliders.