MOPP —  Poster Session   (01-Sep-14   16:00—18:00)
Chair: S. Ramberger, CERN, Geneva, Switzerland
Paper Title Page
MOPP001 First Experimental Results for the Superconducting Half-Wave Resonators for PXIE 46
 
  • Z.A. Conway, A. Barcikowski, 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, T. Reid, K.W. Shepard
    ANL, Argonne, Illinois, USA
  
  Funding: This work was supported by the U.S. Department of energy, Offices of High-Energy Physics and Nuclear Physics, under Contract No. DE-AC02-76-CH03000 and DE-AC02-06CH11357.
The first pair of superconducting niobium half-wave resonators operating at 162.5 MHz for the FNAL PIP-II project are complete and this poster reports the cold test results. These cavities are optimized to accelerate protons/H− from 2 to 10 MeV and build upon optimized electromagnetic designs and processing techniques developed at Argonne for the Intensity Upgrade of the ATLAS superconducting heavy ion accelerator. 		 
 
MOPP002 Design of a Superconducting Quarter-Wave Resonator for eRHIC 49
 
  • S.V. Kutsaev, Z.A. Conway, M.P. Kelly, B. Mustapha, P.N. Ostroumov
    ANL, Argonne, USA
  • S.A. Belomestnykh, I. Ben-Zvi
    Stony Brook University, Stony Brook, USA
  • S.A. Belomestnykh, I. Ben-Zvi, Q. Wu, W. Xu
    BNL, Upton, Long Island, New York, USA
  • B. P. Xiao
    SBU, Stony Brook, New York, USA
  
  Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 and by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357
The electron-ion collider project (eRHIC) at Brookhaven National Laboratory requires a 50 mA 12 MeV electron injector linac for eRHIC main linac and an SRF electron gun for a Coherent electron Cooling (CeC) linac. The necessity to deal with long electron bunches required for both the eRHIC injector and the coherent electron cooler sets the frequency requirement of 84.5 MHz. Quarter wave resonator is a perfect choice for this frequency because of its dimensions, RF parameters and good experience with manufacturing and using them at ANL. Here we present the design and optimization of an 84.5 MHz 2.5 MV superconducting quarter-wave cavity suitable for both machines. One such QWR will be used as a bunching cavity in the injector linac, the other one as the photoemission electron source for the CeC linac. In addition to the optimization of the QWR electromagnetic design we will discuss the tuner design, approaches to cavity fabrication and processing. 		 
 
MOPP003 A Compact Linac Design for an Accelerator Driven System 52
 
  • B. Mustapha, S.V. Kutsaev, 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.
A compact linac design has been developed for an Accelerator Driven System (ADS). The linac is under 150 meters in length and comprises a radio-frequency quadrupole (RFQ) and 20 superconducting modules. Three types of half-wave cavities and two types of elliptical cavities have been designed and optimized for high performance at frequencies of 162.5, 325 and 650 MHz. The lattice is being designed and optimized for operation with a peak power of 25 MW for a 25 mA – 1 GeV proton beam. The cavities RF design as well as the linac lattice will be presented along with end-to-end beam dynamics simulations for beam currents ranging from 0 to 25 mA. 		 
 
MOPP004 Design and Development of Pulsed Modulators for RF Electron Linacs 55
 
  • K.P. Dixit, S. Chandan, N. Chaudhary, R.B. Chavan, L.M. Gantayet, S.R. Ghodke, M. Kumar, K.C. Mittal, H.E. Sarukte, A.R. Tillu, H. Tyagi, V. Yadav
    BARC, Mumbai, India
  
  Pulsed Modulators required for RF sources, based on klystrons and magnetrons, for RF electron linacs have been designed and developed at Electron Beam Centre, BARC, Mumbai, India. Electron guns in these linacs have also been powered by pulsed modulators. Line-type modulators, as well as IGBT-based solid-state modulators have been developed for these applications. A 150 kV/100 A line-type modulator has been tested on klystron to generate 7 MW peak RF Power. Magnetron modulator has undergone testing up to 40 kV, 165 A on resistive load. Solid-state modulator, using fractional-turn pulse transformer has been designed, developed and tested successfully on magnetron load up to output power of 1.3 MW peak. A transformerless solid-state modulator for electron gun of 6 MeV cargo-scanning linac, uses the Marx adder configuration and has been successfully tested up to 40 kV. In addition, line-type modulators for electron guns up to 85 kV have been successfully commissioned and are in operation in the linac systems. This paper describes the salient design features of these modulators, development of pulse transformers, details of test set-up and discusses the test results of these modulators.  
poster icon Poster MOPP004 [2.343 MB]  
 
MOPP005 High Power Electron Accelerator Programme at BARC 58
 
  • K.C. Mittal, S. Acharya, R.I. Bakhtsingh, R. Barnwal, D. Bhattacharjee, S. Chandan, N. Chaudhary, R.B. Chavan, S.P. Dewangan, K.P. Dixit, S. Gade, L.M. Gantayet, S.R. Ghodke, S. Gond, D. Jayaprakash, M. Kumar, M.K. Kumar, H.K. Manjunatha, R.L. Mishra, J. Mondal, B. Nayak, S. Nayak, V.T. Nimje, S. Parashar, R. Patel, R.N. Rajan, P.C. Saroj, H.E. Sarukte, D.K. Sharma, V. Sharma, S.K. Srivasatava, N.T. Thakur, A.R. Tillu, R. Tiwari, H. Tyagi, A. Waghmare, V. Yadav
    BARC, Mumbai, India
  
  Bhabha Atomic Research Centre in India has taken up the indigenous design & development of high power electron accelerators for industrial, research and cargo-scanning applications. For this purpose, Electron Beam Centre (EBC) has been set up at Navi Mumbai, India. Pulsed RF Linacs, with on-axis coupled cavity configuration, include the 10 MeV Industrial RF linac, as well as 9 MeV linac and compact 6 MeV linac for cargo-scanning applications. Industrial DC accelerators include a 500 keV Cockroft-Walton machine and 3 MeV Dynamitron. Several radiation processing applications, such as material modification, food preservation, flue-gas treatment, etc. have been demonstrated using these accelerators. Cargo-scanning linacs have been successfully commissioned and are being characterized for the required x-ray output. A 30 MeV RF Linac, for research applications, such as shielding studies and n-ToF experiments, is being designed and developed. For ADS studies, a 100 MeV, 100 kW RF Linac system is proposed. This paper presents the details of the design of these accelerators, their development, current status and utilization for various applications.  
 
MOPP006
 Beam Dynamics of a 200 MeV High Current CW Superconducting Proton Linac  
 
  • R. Pande, S. Krishnagopal, S. Roy, P. Singh, V.L. Sista
    BARC, Mumbai, India
  
  One of the main components of the Accelerator Driven System (ADS) is a 1 GeV, high intensity CW proton accelerator. In India, it was planned to develop this accelerator in three phases: namely, the low energy linac (20 MeV), the medium energy linac (200 MeV) and high energy linac (1 GeV). In Phase 2 of this programme, at present, a 30 mA, 200 MeV proton linac operating in the CW mode is being designed and built. This linac will consist of an ion source and normal conducting RFQ followed by medium energy superconducting structures like the half wave resonator and single spoke resonator for acceleration of the beam to 200 MeV. Detailed beam dynamics including space charge effects and beam halo studies have been done for designing this linac. The paper will discuss the details of the beam dynamics design for such a linac.  
 
MOPP007 SF6 Gas Monitoring and Safety for DC Electron Beam Accelerator at EBC, Kharghar, Navi Mumbai 61
 
  • S.K. Suneet, S. Acharya, S. Banerjee, R. Barnwal, D. Bhattacharjee, N. Chaudhary, R.B. Chavan, K.P. Dixit, S. Gade, L.M. Gantayet, S.R. Ghodke, S. Gond, B.S. Israel, D. Jayaprakash, N. Lawangare, K. Mahender, R.L. Mishra, K.C. Mittal, B. Nayak, S. Nayak, R. Patel, R.N. Rajan, P.C. Saroj, D.K. Sharma, V. Sharma, M.K. Srvastava, D.P. Suryaprakash, N.T. Thakur, R. Tiwari, A. Waghmare
    BARC, Mumbai, India
  
  A 3 MeV, 30kW DC Industrial electron beam accelerator has been designed, commissioned and tested at Electron beam centre, Kharghar. The accelerator has been tested upto 5 kW power level with SF6 gas at 6 kg/cm2. The accelerating column, high voltage multiplier column, electron gun and its power supply are housed in accelerator tank, which is filled with SF6 gas as gaseous insulator at 6 kg/cm2. The SF6 gas is being used due to high dielectric strength and excellent heat transfer characteristics. The SF6 gas is non toxic and non carcinogenic. The SF6 gas replaces oxygen hence the TLV (threshold limiting value) is 1000 ppm for inhaled gas for persons working on the SF6 gas handling system. The SF6 gas is being green house gas, leak tightness has to monitor in the system and leak if any should be repaired. The gas should be used, recycled and reuse and thus saving the environment. This paper describes the safety and monitoring of the SF6 gas leak, quality and precautions in 3MeV accelerator.  
poster icon Poster MOPP007 [1.389 MB]  
 
MOPP010 Low Charge State Laser Ion Source for the EBIS Injector 64
 
  • M. Okamura, J.G. Alessi, E.N. Beebe, T. Kanesue, C.J. Liaw, V. LoDestro, A.I. Pikin, D. Raparia, J. Ritter
    BNL, Upton, Long Island, New York, USA
  • Y. Fuwa, S. Ikeda, M. Kumaki
    RIKEN, Saitama, Japan
  
  Funding: NASA
In March 2014, we have successfully commissioned a newly designed low charge high brightness laser ion source (LIS) which delivers various singly charged heavy ions to the electron beam ion source (EBIS) at Brookhaven National Laboratory. Now the LIS is used at routine operation of the RHIC-AGS accelerator complex and is providing stable less-contaminated beams. The laser power density was optimized to provide singly charged ions with low material consumption rate. The nominal laser energy on the target is around 500 mJ with 1064 nm Nd:YAG of the wave length. The induced plasma by the laser is transported through a 3 m pipe to stretch ion beam pulse length to match the EBIS’s requirement and the degradation of the beam current caused by the long drift section of the pipe can be compensated by a longitudinal magnetic filed induced by a coil surrounding the pipe. We also employed a twin laser system to extend the beam width further. At the conference, we will discuss the effect of the new LIS on the various accelerated beams through the EBIS, RFQ and IH-linac. 		 
 
MOPP011 Reliability and Intensity Upgrade for 200 MeV Linac at Brookhaven National Laboratory 67
 
  • D. Raparia, J.G. Alessi, B. Briscoe, D.M. Gassner, O. Gould, T. Lehn, V. Lo Destro, J. Ritter, W. Shaffer, A. Zelenski
    BNL, Upton, Long Island, New York, USA
  
  Brookhaven 200 MeV H− linac has been operating for last 44 years and providing beam to nuclear physics program and isotope program. Two upgrade programs are in progress to make machine more reliable and to double the intensity. This paper will discuss in detail these upgrade programs.  
 
MOPP012 Beam Commissioning of the SRF 704 MHz Photoemission Gun 70
 
  • W. Xu, S.A. Belomestnykh, I. Ben-Zvi, D.M. Gassner, H. Hahn, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, R.F. Lambiase, G.T. McIntyre, D. Phillips, V. Ptitsyn, K.S. Smith, R. Than, D. Weiss, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • S.A. Belomestnykh, I. Ben-Zvi, V. Ptitsyn
    Stony Brook University, Stony Brook, USA
  • D. Holmes
    AES, Medford, New York, USA
  
  Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
A 704 MHz superconducting RF photoemission electron gun for the R&D ERL project is under comissioning at BNL. Without a cathode insert, the SRF gun achieved its design goal: an accelerating voltage of 2 MV in CW mode. During commissioning with a copper cathode insert it reached 1.9 MV with 18% duty factor, which is limited by mulitpacting in a choke-joint cathode stalk. A new cathode stalk has been designed to eliminate multipacting in the choke-joint. This paper presents recent commissioning results, including cavity commissioning without the cathode stalk insert, first beam commissioning of the SRF gun in pulsed regime, and the design of a multipacting-free cathode stalk. 		 
 
MOPP013 Vertical Test Results of 704 MHz BNL3 SRF Cavities 73
 
  • W. Xu, S.A. Belomestnykh, I. Ben-Zvi, H. Hahn, R. Porgueddu, R. Than, D. Weiss
    BNL, Upton, Long Island, New York, USA
  • S.A. Belomestnykh, I. Ben-Zvi
    Stony Brook University, Stony Brook, USA
  • C.H. Boulware, T.L. Grimm
    Niowave, Inc., Lansing, Michigan, USA
  • M.D. Cole, D. Holmes, T. Schultheiss
    AES, Medford, New York, USA
  
  Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE, and Award No. DE-SC0002496 to Stony Brook University with the U.S. DOE.
An electron-ion collider (eRHIC) proposed at BNL requires superconducting RF cavities able to support high average beam current. A 5-cell niobium SRF cavity, called BNL3, was designed for a conventional lattice eRHIC design. To avoid inducing emittance degradation and beam-break-up (BBU), the BNL3 cavity was optimized to damp all dangerous higher-order-modes (HOMs) by employing a large beam pipes and coaxial antenna-type couplers. Additionally, the cavity was designed for an acceptable cryogenic load and peak surface RF fields. Two BNL3 cavities have been fabricated and tested at a vertical test facility at BNL. This paper addresses development of the SRF cavities for eRHIC, including SRF cavity design, fabrication and test results. 		 
 
MOPP014
 Cryogenic System and Helium Gas Recovery System in IMP  
 
  • X.H. Guo
    IMP, Lanzhou, People's Republic of China
  
  In order to meet the requirements of ADS Injector II project which is now designing and building in IMP, CAS, a liquid helium cryogenic system and a helium gas recovery system are building simultaneously. This paper presents the two systems in detials.  
 
MOPP015 High Energy Electron Radiography Experiment Research Based on Picosecond Pulse-width Bunch 76
MOPOL01   use link to see paper's listing under its alternate paper code  
 
  • Q.T. Zhao, S. Cao, R. Cheng, X.K. Shen, Z.M. Zhang, Y.T. Zhao
    IMP, Lanzhou, People's Republic of China
  • Y.-C. Du
    TUB, Beijing, People's Republic of China
  • W. Gai
    ANL, Argonne, Illinois, USA
  
  A new scheme is proposed that high energy electron beam as a probe is used for time resolved imaging measurement of high energy density materials, especially for high energy density matter and inertial confinement fusion. The first picosecond pulse-width electron radiography experiment was achieved by Institute of Modern Physics, Chinese Academy of Sciences and Tinghua University (THU), based on THU Linear electron accelerator (LINAC). It is used for principle test and certifying that this kind of LINAC with ultra-short pulse electron bunch can be used for electron radiography. The experiment results, such as magnifying factor and the imaging distortion, are consistent with the beam optical theory well. The 2.5 um RMS spatial resolution has been gotten with magnifying factor 46, with no optimization the imaging lens section. It is found that in the certain range of magnifying factor, the RMS spatial resolution will get better with bigger magnifying factor. The details of experiment set up, results, analysis and discussions are presented here.  
poster icon Poster MOPP015 [2.866 MB]  
 
MOPP016 Extracting Superconducting Parameters from Surface Resistivity by Using Inside Temperature of SRF Cavities 80
 
  • G.M. Ge, G.H. Hoffstaetter, M. Liepe, H. Padamsee, V.D. Shemelin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  The surface resistance of an RF superconductor depends on the surface temperature, the residual resistance and various superconductor parameters. These parameters can be determined by measuring the quality factor of a SRF cavity in helium-baths of different temperatures. The surface resistance can be computed from Q0 for any cavity geometry, however it is less simple to determine the temperature of the surface when only the temperature of the helium bath is known. Traditionally, it was approximated that the surface temperature on the inner surface of the cavity is the same as the temperature of the bath. This is a good approximation at small RF-field losses on the surface, but to determine the field dependence of Rs, one cannot be restricted to small field losses. Here we show how computer simulations can be used to determine the inside temperature so that Rs(Tin) can then be used to extract superconductor parameters. The computer code combines the well-known programs HEAT and SRIMP. We find that the error of the incorrect fitting method is about 10% at high RF-fields.  
 
MOPP017 Cool Down and Flux Trapping Studies on SRF Cavities 84
MOPOL07   use link to see paper's listing under its alternate paper code  
 
  • D. Gonnella, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Recent results from Cornell and FNAL have shown that cool down rate can have a strong impact on the residual resistance of a superconducting RF cavity during operation. We have studied the effect of cool down rate, gradient, and external magnetic field during cool down on the residual resistance of an EP, EP+120C baked, and nitrogen-doped cavities. For each cavity, faster cool down and large gradient resulted in lower residual resistance in vertical test. The nitrogen-doped cavities showed the largest improvement with fast cool down, while the EP+120C cavity showed the smallest. The cavities were also placed in a uniform external magnetic field and residual resistance was measured as a function of applied field and cool down rate. We show that the nitrogen-doped cavity was the most susceptible to losses from trapped flux and the EP+120C cavity was least susceptible. These measurements provide new insights into understanding the physics behind the observed impact of cool down rates and gradients on the performance of cavities with differing preparations.  
 
MOPP018 Nitrogen-Doped 9-Cell Cavity Performance in the Cornell Horizontal Test Cryomodule 88
 
  • D. Gonnella, R.G. Eichhorn, F. Furuta, G.M. Ge, D.L. Hall, Y. He, G.H. Hoffstaetter, M. Liepe, T.I. O'Connel, S. Posen, P. Quigley, J. Sears, V. Veshcherevich
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • A. Grassellino, A. Romanenko
    Fermilab, Batavia, Illinois, USA
  
  Funding: U.S. Department of Energy
Cornell has recently completed construction and qualification of a horizontal cryomodule capable of holding a 9-cell ILC cavity. A nitrogen-doped niobium 9-cell cavity was assembled into the Horizontal Test Cryomodule (HTC) with a high Q input coupler and tested. We report on results from this test of a nitrogen-doped cavity in cryomodule and discuss the effects of cool down rate and thermal cycling on the residual resistance of the cavity. 		 
 
MOPP019 Nb3Sn Materials Studies 92
SUPG016   use link to see paper's listing under its alternate paper code  
 
  • S. Posen, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • Th. Proslier
    ANL, Argonne, Illinois, USA
  
  Nb3Sn is a very promising material for use in SRF cavity applications, potentially offering significant improvements in quality factor and energy gradient compared to niobium. In order to better understand how to optimize this material for SRF applications, Nb3Sn samples were prepared at Cornell via vapor deposition, using varying parameters in the coating process. Microscopic studies were performed with SEM/EDX, and studies were performed on bulk samples to measure secondary electron yield, energy gap, and upper critical magnetic field. The results are presented here, with discussion for how they might point the way towards reaching even higher fields in Nb3Sn cavities.  
poster icon Poster MOPP019 [2.742 MB]  
 
MOPP020 Input Couplers for Cornell ERL 95
 
  • R.G. Eichhorn, P. Quigley, V. Veshcherevich
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • S.A. Belomestnykh
    BNL, Upton, Long Island, New York, USA
  
  Cornell has developed two types of input couplers for the Energy Recovery Linac (ERL) Project. Both couplers are 1.3 GHz CW coaxial couplers. The coupler for ERL injector is a 65 kW CW coupler with variable coupling (Qext = 9*E4 to 9*E5). The coupler for ERL main linac is a 5 kW CW coupler with fixed coupling. It can be easily modified for variable coupling operation. Couplers have been tested on test stands and in cryomodules and showed good performance.  
 
MOPP021 XFEL Cryomodule Transportation: from the Assembly Laboratory in CEA-Saclay (France) to the Test-Hall in DESY-Hamburg (Germany) 98
 
  • S. Barbanotti, K. Jensch, W. Maschmann, O. Sawlanski
    DESY, Hamburg, Germany
  
  The one hundred, 12 m long XFEL 1.3 GHz cryomodules are assembled at CEA Saclay (F) and have therefore to be transported, fully assembled, to the installation site in DESY Hamburg (D). Various studies and tests have been performed to assess and minimize the risk of damages during transportation; a new transport frame and a specialised company are being used for the series transportation. This paper resumes the studies performed, describes the final configuration adopted for the series transportation and the results obtained for the first XFEL modules.  
 
MOPP023 X-band Technology for FEL Sources 101
MOPOL02   use link to see paper's listing under its alternate paper code  
 
  • G. D'Auria, S. Di Mitri, C. Serpico
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • E. Adli
    University of Oslo, Oslo, Norway
  • A.A. Aksoy, Ö. Yavaş
    Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
  • D. Angal-Kalinin, J.A. Clarke
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • C.J. Bocchetta, A.I. Wawrzyniak
    Solaris, Kraków, Poland
  • M.J. Boland, T.K. Charles, R.T. Dowd, G. LeBlanc, Y.E. Tan, K.P. Wootton, D. Zhu
    SLSA, Clayton, Australia
  • G. Burt
    Lancaster University, Lancaster, United Kingdom
  • N. Catalán Lasheras, A. Grudiev, A. Latina, D. Schulte, S. Stapnes, I. Syratchev, W. Wuensch
    CERN, Geneva, Switzerland
  • W. Fang, Q. Gu
    SINAP, Shanghai, People's Republic of China
  • E.N. Gazis
    National Technical University of Athens, Athens, Greece
  • M. Jacewicz, R.J.M.Y. Ruber, V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  • X.J.A. Janssen
    VDL ETG, Eindhoven, The Netherlands
  
  As is widely recognized, fourth generation Light Sources are based on FELs driven by Linacs. Soft and hard X-ray FEL facilities are presently operational at several laboratories, SLAC (LCLS), Spring-8 (SACLA), Elettra-Sincrotrone Trieste (FERMI), DESY (FLASH), or are in the construction phase, PSI (SwissFEL), PAL (PAL-XFEL), DESY (European X-FEL), SLAC (LCLS II), or are newly proposed in many laboratories. Most of the above mentioned facilities use NC S-band (3 GHz) or C-band (6 GHz) linacs for generating a multi-GeV low emittance beam. The use of the C-band increases the linac operating gradients, with an overall reduction of the machine length and cost. These advantages, however, can be further enhanced by using X-band (12 GHz) linacs that operate with gradients twice that given by C-band technology. With the low bunch charge option, currently considered for future X-ray FELs, X-band technology offers a low cost and compact solution for generating multi-GeV, low emittance bunches. The paper reports the ongoing activities in the framework of a collaboration among several laboratories for the development and validation of X-band technology for FEL based photon sources.  
 
MOPP024 Perspectives of the S-Band Linac of FERMI 105
 
  • A. Fabris, P. Delgiusto, M. Milloch, C. Serpico
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • A. Grudiev
    CERN, Geneva, Switzerland
  
  The S-band linac of FERMI, the seeded Free Electron Laser (FEL) located at the Elettra laboratory in Trieste, has reached the peak on-crest electron energy of 1.55 GeV required for FEL-2 with the present layout. Different ways are being considered to extend the operating energy of the S-band linac up to 1.8 GeV. At the same time upgrades on the existing systems are investigated to address the requirements of operability of a users facility. This paper provides an overview of the developments that are under consideration and discusses the requirements and constraints for their implementation.  
 
MOPP025 Longitudinal Beam Profile Measurements in Linac4 Commissioning 108
 
  • G. Bellodi, V.A. Dimov, J.-B. Lallement, A.M. Lombardi, U. Raich, F. Roncarolo, F. Zocca
    CERN, Geneva, Switzerland
  • M. Yarmohammadi Satri
    IPM, Tehran, Iran
  
  Linac4, the future 160 MeV H− injector to the CERN Proton Synchrotron Booster, is presently under construction at CERN as a central step of the planned upgrade of the LHC injectors. The Linac front-end, composed of a 45 keV ion source, a Low Energy Beam Transport (LEBT), a 352.2 MHz Radio Frequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) housing a beam chopper, has been installed and commissioned. Precise measurements of the longitudinalμbunch profiles of ion beams were possible with the help of a Bunch Shape Monitor (BSM) developed at INR Moscow. These were crucial for the successful commissioning of the three RF buncher cavities mounted along the MEBT and well complemented with higher precision the information provided in parallel by spectrometer measurements.  
 
MOPP026 Actively Cooled RF Power Coupler : Theoretical and Experimental Studies 111
 
  • R. Bonomi, V. Parma
    CERN, Geneva, Switzerland
  
  In cryostats for Super-conducting Radio Frequency Cavities, the heat loads introduced by the high-power RF couplers represent an important fraction of the overall static thermal budget. Working at low operating temperature benefits from a reduced surface resistance (low dynamic losses) but is penalized by the high refrigeration cost. The external conductor of RF coaxial couplers provides a direct conduction path from ambient to cryogenic temperature plus is heated by resistive power deposition. Heat interception is therefore essential to contain heat in-leaks: a double-walled external conductor with a properly designed gas cooling effectively reduces heat loads to the cold bath by 1 order of magnitude. This paper presents the thermal design of the RF power coupler of the Superconducting Proton Linac (SPL) at CERN, featuring a helium vapour cooling between 4.5 K and ambient temperature. Numerical models, which can be used as design tools for other applications, have been developed to assess efficiency and thermal performance. A full-size mock-up cooled by nitrogen has been built for experimental validation. Comparison between calculations and measurements is presented and discussed.  
 
MOPP028 New Criterion for Shape Optimization of Normal-Conducting Accelerator Cells for High-Gradient Applications 114
 
  • K.N. Sjobak, A. Grudiev
    CERN, Geneva, Switzerland
  • E. Adli
    University of Oslo, Oslo, Norway
  
  When optimizing the shape of high-gradient accelerating cells, the goal has traditionally been to minimize the peak surface electric field / gradient, or more recently minimizing the peak modified Poynting vector / gradient squared. This paper presents a method for directly comparing these quan- tities, as well as the power flow per circumference / gradient squared. The method works by comparing the maximum tolerable gradient at a fixed pulse length and breakdown rate that can be expected from the different constraints. The paper also presents a set of 120° phase-advance cells for traveling wave structures, which were designed for the new CLIC main linac accelerating structure, and which are optimized according to these criteria.  
 
MOPP029 Overview of the New High Level Software Applications Developed for the HIE-ISOLDE Superconducting Linac 117
 
  • D. Lanaia, M.A. Fraser, D. Voulot
    CERN, Geneva, Switzerland
  
  The High Intensity and Energy (HIE) ISOLDE project consists of an upgrade of the ISOLDE facility. With the installation of 32 independently-phased, superconducting quarter-wave cavities the energy of post-accelerated radioactive beams will be increased from 3 MeV/u to over 10 MeV/u. The large number of cavities will increase the number of parameters to optimise. In order to ensure a fast set-up of the machine during operation and commissioning, new software applications have been developed and an upgrade of the existing software was carried out. Four high level applications have been specifically developed for the SC linac. The first allows the conversion of optics settings into machine settings, and vice versa. The second will aid the phasing of the cavities using beam energy measurements. A third application will provide absolute measurements of the beam energy by means of a time-of-flight system. The last application will automatically generate the phase and voltage settings for the cavities SC linac. In this contribution we will present the new applications and outline how these will be used in the operation of the new SC linac.  
poster icon Poster MOPP029 [1.568 MB]  
 
MOPP030 CALIFES: A Multi-Purpose Electron Beam for Accelerator Technology Tests 121
 
  • J.L. Navarro Quirante, R. Corsini, W. Farabolini, D. Gamba, A. Grudiev, M.A. Khan, T. Lefèvre, S. Mazzoni, R. Pan, F. Peauger, F. Tecker, N. Vitoratou, K. Yaqub
    CERN, Geneva, Switzerland
  • W. Farabolini, F. Peauger
    CEA/DSM/IRFU, France
  • D. Gamba
    JAI, Oxford, United Kingdom
  • M.A. Khan, K. Yaqub
    PINSTECH, Islamabad, Pakistan
  • J. Ögren, R.J.M.Y. Ruber
    Uppsala University, Uppsala, Sweden
  • N. Vitoratou
    Thessaloniki University, Thessaloniki, Greece
  
  The Compact Linear Collider (CLIC) project aims to accelerate and collide electrons and positrons up to 3 TeV center-of-mass energy using a novel two-beam acceleration concept. To prove the feasibility of this technology the CLIC Test Facility CTF3 has been operated during the last years. CALIFES (Concept d’Accélérateur Linéaire pour Faisceau d’Electron Sonde) is an electron linac hosted in the CTF3 complex, which provides a flexible electron beam and the necessary equipment to probe both the two-beam acceleration concept and novel instrumentation to be used in the future CLIC collider. In this paper we describe the CALIFES Linac and its beam characteristics, present recent test results, outline its future program on two-beam module testing and finally discuss about possible future applications as a multi-purpose accelerator technology test facility.  
 
MOPP032 Experimental Verification Towards Feed-Forward Ground Motion Mitigation at ATF2 124
MOPOL03   use link to see paper's listing under its alternate paper code  
 
  • J. Pfingstner, K. Artoos, C. Charrondière, S.M. Janssens, M. Patecki, Y. Renier, D. Schulte, R. Tomás
    CERN, Geneva, Switzerland
  • A. Jeremie
    IN2P3-LAPP, Annecy-le-Vieux, France
  • K. Kubo, S. Kuroda, T. Naito, T. Okugi, T. Tauchi, N. Terunuma
    KEK, Ibaraki, Japan
  
  Without counter measures, ground motion effects would deteriorate the performance of future linear colliders to an unacceptable level. An envisioned new ground motion mitigation method (based on feed-forward control) has the potential to improve the performance and to reduce the system cost compared to other proposed methods. For the experimental verification of this feed-forward scheme, a dedicated measurement setup has been installed at ATF2 at KEK. In this paper, the progress on this experimental verification is described. An important part of the feed-forward scheme could be already demonstrated, namely the prediction of the orbit jitter due to ground motion measurements.  
 
MOPP033 Design, Hardware Tests and First Results From the CLIC Drive Beam Phase Feed-Forward Prototype at CTF3 128
SUPG037   use link to see paper's listing under its alternate paper code  
 
  • J. Roberts, A. Andersson, P.K. Skowronski
    CERN, Geneva, Switzerland
  • P. Burrows, G.B. Christian, C. Perry
    JAI, Oxford, United Kingdom
  • A. Ghigo, F. Marcellini
    INFN/LNF, Frascati (Roma), Italy
  
  In the CLIC two beam acceleration concept the phase synchronisation between the main beam and the RF power extracted from the drive beam must be maintained to within 0.2 degrees of 12 GHz. A drive beam phase feed-forward system with bandwidth above 17.5 MHz is required to reduce the drive beam phase jitter to this level. The system will correct the drive beam phase by varying the path length through a chicane via the use of fast strip line kickers. A prototype of the system is in the final stages of installation at the CLIC test facility CTF3 at CERN. This paper presents results from preparations for the phase feedforward system relating to optics improvements, the development of a slow phase feedback that will be run in parallel with the feedforward system and first tests of the kicker amplifier and kickers.  
 
MOPP034 Beam Dynamics Studies of the CLIC Drive Beam Injector 131
SUPG027   use link to see paper's listing under its alternate paper code  
 
  • S. Sanaye Hajari, S. Döbert, H. Shaker
    CERN, Geneva, Switzerland
  • S. Sanaye Hajari, H. Shaker
    IPM, Tehran, Iran
  
  In the Compact Linear Collider (CLIC) the RF power for the acceleration of the Main Beam is extracted from a high-current Drive Beam that runs parallel with the main linac. The beam in the Drive Beam Accelerator is phase coded. This means only every second accelerator bucket is occupied. However, a few percent of particles are captured in wrong buckets, called satellite bunches. The phase coding is done via a sub-harmonic bunching system operating at a half the acceleration frequency. The beam dynamics of the Drive Beam injector complex has been studied in detail and optimised. The model consists of a thermionic gun, the bunching system followed by some accelerating structures and a magnetic chicane. The bunching system contains three sub-harmonic bunchers, a prebuncher and a tapered travelling wave buncher all embedded in a solenoidal magnetic field. The simulation of the beam dynamics has been carried out with PARMELA with the goal of optimising the overall bunching process and in particular decreasing the satellite population and the beam loss in magnetic chicane and in transverse plane limiting the beam emittance growth.  
 
MOPP035 Bead-Pull Measurement Method and Tuning of a Prototype CLIC Crab Cavity 134
 
  • R. Wegner, W. Wuensch
    CERN, Geneva, Switzerland
  • G. Burt, B.J. Woolley
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  
  A bead-pull method has been developed which measures in a single bead passage the amplitude and phase advance of deflecting mode travelling wave structures. This bead-pull method has been applied to measure and tune a Lancaster University-designed prototype crab cavity for CLIC. The technique and tuning results are described.  
 
MOPP036 Estimation of the Thermal Load and Signal Level of the ESS Wire Scanner 137
 
  • B. Cheymol
    ESS, Lund, Sweden
  
  The European Spallation Source (ESS), to be built in the south of Sweden, will use a 2 GeV superconducting linac to produce the worlds most powerful neutron source with a beam power of 5 MW. A number of wire scanners will be used to characterize the beam transverse profile. The design of the wire has to cope with the high power density of the beam and must satisfy the overall measurement robustness, accuracy and sensitivity for the commissioning and the regular retuning phase of the ESS linac. This paper describes the preliminary design of the wire scanner system in the normal conducing linac as well as in the superconducting linac.  
 
MOPP037 Conceptual Design of the ESS DTL Faraday Cup 140
 
  • B. Cheymol, E. Lundh
    ESS, Lund, Sweden
  
  The DTL section of the ESS linac will accelerate the beam form 3.6 MeV to 90 MeV at a peak current of 62.5 mA. It is foreseen to install after each DTL tank a Faraday cup for beam current and the beam transmission measurements during retuning phase. An energy degrader will be positioned in front of the in order to perform a low resolution phase scan of the DTL tank before injecting the beam in the downstream structure. This paper describes the preliminary studies of the Faraday cup, mainly focus on the energy degrader.  
 
MOPP038 Longitudinal Bunch Profile Monitoring at the ESS Linac 143
 
  • I. Dolenc Kittelmann, B. Cheymol
    ESS, Lund, Sweden
  
  The European Spallation Source (ESS), which is currently under construction, will be a neutron source based on 5MW, 2GeV proton linac. This high intensity linac will among other beam instrumentation require longitudinal bunch profile monitors. These shall be used during the commissioning phase and start-up periods for beam dynamics optimization and beam loss reduction. The paper focuses on the preliminary studies concerning the longitudinal bunch profile monitoring at the ESS linac.  
 
MOPP039 Dynamics of Bunches Partially Chopped with the MEBT Chopper in the ESS Linac 146
 
  • R. Miyamoto, B. Cheymol, R. De Prisco, M. Eshraqi, A. Ponton, E. Sargsyan
    ESS, Lund, Sweden
  • I. Bustinduy
    ESS Bilbao, Bilbao, Spain
  
  The front-end of a hadron linac typically has a transient time during turning on and off and bunches in the head and tail of a pulse from this period likely have wrong parameters and a risk to cause beam losses. A risk of losses must be avoided as possible in a high power machine so these bunches are removed with deflectors called choppers in the ESS Linac. From experiences of other machines, a rise time of a chopper as fast as one RF period (2.84~ns for ESS) is challenging to achieve and not necessarily needed with no ring to inject like ESS, and hence a 10~ns rise time is planned for a chopper in the medium energy beam transport of ESS. This, however, means that several bunches receive intermediate deflections and may propagate with large trajectory excursions. This paper studies dynamics of such partially chopped bunches in detail to ensure no significant loss is caused by them.  
 
MOPP040 Application Investigation of High Precision Measurement for Basic Cavity Parameters at ESS 149
 
  • R. Zeng
    ESS, Lund, Sweden
  • P. Jonsson
    Lund University, Lund, Sweden
  • W. Schappert
    Fermilab, Batavia, Illinois, USA
  
  The ESS cavity control and operation methods/algorithms are challenging due to the use of long pulse, higher beam intensity, high beam power, high gradient, uncertainties in spoke cavities and high demands for energy efficiency and availability. Suitable and effective solutions could make use of modern technologies (flexible FPGA, faster CPU, bigger memory, faster communication speed), novel measuring techniques, accurate system modeling, and advanced control concept. Those possible implementations are essential to a better understanding, and thus a better operation of ESS cavity especially SRF cavities. All these concepts rely on high precision measurement of basic cavity parameters and consequent high quality data with high resolution, high precision and completeness. This paper focuses on how high precision measurement will address the challenges at ESS on the following topics: long pulse lorentz force detuning, high precision phase and amplitude setting, heavy beam loading compensation and power overhead reduction.  
 
MOPP041 Commissioning Plan for the FRIB Driver Linac* 152
 
  • M. Ikegami, L.T. Hoff, S.M. Lidia, F. Marti, G. Pozdeyev, T. Russo, R.C. Webber, J. Wei, Y. Yamazaki
    FRIB, East Lansing, Michigan, USA
  
  Funding: * Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The FRIB driver linac accelerates CW beams of all stable ions up to uranium to the energy of 200 MeV/u with the beam power of 400 kW. We plan to start staged beam commissioning in December 2017 in parallel with ongoing installation activities. This allows early recognition of technical issues, which is essential for smooth commissioning and early completion of commissioning goals. As the interlaced nature of commissioning and installation poses both scheduling challenges and special safety issues, it is essential to develop a commissioning plan with focused consideration of each. In this paper, we present a commissioning plan with emphasis on its characteristic features. 		 
 
MOPP042
 Validation of FRIB Fundamental Power Couplers at MSU  
 
  • J. Popielarski, S.K. Chandrasekaran, A. Facco, M. Hodek, J.P. Ozelis, L. Popielarski, K. Saito, S. Stark, G. Wu, Z. Zheng
    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.
For the FRIB driver linac, two different types of fundamental power couplers will be used to provide cw rf power to four cavity types. A cold window design is being used to power the two 80.5 MHz QWR cavity types for β=0.041 and β=0.085. A warm window design is being used to power the 322 MHz HWR cavity types for β = 0.29 and β = 0.53. Topics discussed include coupler preparation & assembly methods, acceptance criteria, diagnostics and RF conditioning. 		 
 
MOPP044 MSU RE-Accelerator ReA3 0.085 QWR Cryomodule Status 155
 
  • T. Xu, B. Bird, F. Casagrande, J.L. Crisp, K.D. Davidson, C. Dudley, A. Facco, P.E. Gibson, I. Grender, L. Hodges, K. Holland, M.J. Johnson, S. Jones, B. Laumer, D. Leitner, A. Mccartney, S.J. Miller, D. Morris, S. Nash, J.P. Ozelis, J. Popielarski, L. Popielarski, R. Rosas, R.J. Rose, K. Saito, M. Thrush, R. Walker, J. Wei, W. Wittmer, Y. Xu
    FRIB, East Lansing, Michigan, USA
  • B. Arend, J. Ottarson, D.P. Sanderson, D. Wahlquist, J. Wenstrom
    NSCL, East Lansing, Michigan, USA
  • M. Leitner
    LBNL, Berkeley, California, USA
  
  ReA3 β=0.085 QWR cryomodule is the third cryomodule for the superconducting LINAC of ReA3 reaccelerated beam facility, which will bring the maximum beam energy to 3 MeV/u for heavy ions. This cryomodule consists of 8 β=0.085 QWR cavities and 3 9T superconducting solenoids and operates at 4K. Qualification of cavities and FPCs and the construction of cold mass was completed in 2013. The installation of the module was completed this summer. Functioning not only as an important part of the ReA3 facility, cryomodule 3 also serves as a test bed for FRIB driver Linac and demonstrated the technology needed for FRIB CMs. Here we report the construction, installation and testing of the β=0.085 cryomodule and the development of the critical components.
Project funded by Michigan State University 		 
 
MOPP045 Progress and Plan of Open XAL Physics Application for FRIB 158
 
  • Y. Zhang, P. Chu, D.G. Maxwell
    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
FRIB driver linac will deliver heavy ion beams with beam energy above 200 MeV/u, and beam power on target up to 400 kW. Commissioning, tuning, and beam power ramping up of the world’s first SRF linac for high-power heavy-ion beams will be challenge, and developments of necessary physics application software tools are very important. In this paper, our major progress and the development plan of physics application software for the FRIB linac within Open XAL frameworks are discussed, which include the FRIB linac online model, MySQL database for physics applications, virtual accelerator application, and several other pilot physics applications. Deploying and initial testing of Open XAL and those pilot applications for FRIB are currently ongoing for a new cryomodule at Michigan State University. 		 
 
MOPP046 On the Design of Higher Order Mode Antenna for LCLS II 161
 
  • M.H. Awida, I.V. Gonin, T.N. Khabiboulline, K.S. Premo, O.V. Pronitchev, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
The upgrade of the Linac Coherent Light Source (LCLS-II) necessitates a major modification to the higher order mode (HOM) antenna of the conventional ILC elliptical 9-cell cavity. Due to the continuous wave nature of the proposed LCLS II Linac, the HOM antenna is required to bare higher RF losses. A modified design of the HOM antenna is presented in this paper ahead with a thorough thermal quench study in comparison with the conventional ILC design. 		 
 
MOPP049 Dipole Kick due to Geometry Asymmetries in HWR for PXIE 165
 
  • P. Berrutti, T.N. Khabiboulline, V.A. Lebedev, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359
Project X Injector Experiment (PXIE) will have a family of half wave resonators having frequency=162.5 MHz and beta optimal=0.11. During cavity production, when the niobium parts are assembled and welded together, it is fundamental to control the frequency of the accelerating mode in order to meet the specified operating value. For the HWR of PXIE the tuning will be achieved by trimming one end of the resonator only, this will introduce unwanted asymmetry in the cavity geometry leading to a dipole kick for the particles traveling through the cavity. The cavity geometry will be different from the ideal, once the cavity is assembled, because of small misalignment of the niobium parts and because of the welding shrinkage. Misalignments of the inner conductor and the beam pipes can be expected. The asymmetry due to tuning process along with production misalignments, have been simulated and the equivalent dipole kick has been calculated. 		 
poster icon Poster MOPP049 [1.441 MB]  
 
MOPP050 Transmission Efficiency Measurement at the FNAL 4-rod RFQ 168
 
  • J.-P. Carneiro, F.G. Garcia, J.-F. Ostiguy, A. Saini, R.M. Zwaska
    Fermilab, Batavia, Illinois, USA
  • B. Mustapha, P.N. Ostroumov
    ANL, Argonne, Illinois, USA
  
  This paper presents measurements of the beam transmission performed on the 4-rods RFQ currently under operation at Fermilab. The beam current has been measured at the RFQ exit as a function of the magnetic field strength in the 2 LEBT solenoids. This measurement is compared with a scan performed on the Fermi Grid with the beam dynamics code TRACK. A particular attention is given to the impact, on the RFQ beam transmission, of the space-charge neutralization in the LEBT and of the field asymmetry on the 4-rods RFQ.  
 
MOPP052 Development of 5-Cell β=0.9 650 MHz Elliptical Cavities for Project X 171
 
  • I.V. Gonin, M.H. Awida, M.H. Foley, A. Grassellino, C.J. Grimm, T.N. Khabiboulline, A. Lunin, A.M. Rowe, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Several 5-cell 650 MHz elliptical cavities have been fabricated for the PIP-II Project. Two versions of the cavities have been designed to accelerate protons of relative group velocity of β=0.9 and β=0.92 in the high energy region of the linac. In this paper, we report the development status of these cavities, summarize the results of the quality control measurements performed on five initial prototypes, and outline the VTS test results.  
 
MOPP053 TTF-III Coupler Modification for CW Operation 174
 
  • I.V. Gonin, T.N. Khabiboulline, A. Lunin, O.V. Prokofiev, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  LCLS-II linac is based on XFEL/ILC superconducting technology, but CW regime of operation requires the modification of components to satisfy LCLS-II requirements. TTF-III coupler is considered as a candidate for a fundamental power coupler for the 1.3 GHz 9-cell accelerating structure at the LCLS-II project. In this paper we discuss the results of multiphysics analysis of the coupler working at various operating regimes. Two major modifications are proposed in order to meet the LCLS-II requirements and eliminate possible overheating: reducing the length of antenna (cold part) and increasing the thickness of a cooper plating on the inner conductor of the warm part of the coupler.  
 
MOPP054 Continuous-Wave Horizontal Tests of Dressed 1.3 GHz SRF Cavities for LCLS-II 177
 
  • A. Hocker, A.C. Crawford, M. Geynisman, J.P. Holzbauer, A. Lunin, D.A. Sergatskov, N. Solyak, A.I. Sukhanov
    Fermilab, Batavia, Illinois, USA
  
  Funding: United States Department of Energy, Contract No. DE-AC02-07CH11359
Fermilab’s Horizontal Test Stand has recently been upgraded to provide CW RF testing capabilities in support of the LCLS-II project at SLAC. Several cavities have been tested in this new configuration in order to validate component designs and processes for meeting the requirements of LCLS-II. Areas of study included gradient and Q0 performance and their dependence on extrinsic factors, thermal performance of the input coupler and HOM feedthroughs, and microphonics and RF control. A description of the testing and the results obtained are presented. 		 
poster icon Poster MOPP054 [0.276 MB]  
 
MOPP055 RF Tests of Dressed 325 MHz Single-Spoke Resonators at 2 K 180
 
  • A. Hocker, E. Cullerton, B.M. Hanna, W. Schappert, A.I. Sukhanov
    Fermilab, Batavia, Illinois, USA
  
  Funding: United States Department of Energy, Contract No.DE- AC02-07CH11359
Fermilab has recently completed an upgrade to its spoke resonator test cryostat to enable testing of cavities in superfluid helium. Two single-spoke resonators with differing helium vessel designs have been tested in this new configuration. Gradient and Q0 performance was studied along with microphonics control and sensitivity of the resonant frequency to pressure variations. A description of the testing and the results obtained are presented. 		 
poster icon Poster MOPP055 [0.437 MB]  
 
MOPP057
 Effects of High Temperature Treatments on Conflat© Flanges of Various Grades of Stainless Steel  
 
  • L. Ristori
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359
Particle accelerators employ a variety of beam line components to accelerate, focus and manipulate beams. Such components are joined at the interfaces by utilizing flanges capable of establishing ultra-high vacuum seals. Certain processes in the manufacturing stages and in the surface preparation stages such as furnace brazing or hydrogen degassing produce high temperatures that can compromise the performance of the flanges by modifying the properties of the flange bulk and surface material. Commercial specifications for these flanges discourage heating above 450'C and pose restrictions on the manufacturing and treatment operations on beam line components. In this paper we present a systematic study performed on commercially available Conflat flanges made of different grades of stainless steel material. The study examined different heat treatments and repeated assemblies while observing variations in geometry, physical properties and sealing effectiveness. 		 
 
MOPP058 Z-slicer: A Simple Scheme for Electron Beam Current Profile Shaping in a Linac 183
 
  • J.C.T. Thangaraj, C.M. Baffes, D.R. Broemmelsiek, D.J. Crawford, R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
  • W.B. Wortley
    University of Rochester, Rochester, New York, USA
  
  Short bunches are a premium at accelerator facilities and their applications include THz generation, short bunch production, shaped bunch production, etc. In this work we report on the design of an experiment involving an electron beam about 50 MeV that will be intercepted by a set of metallic slits inside a bunch compressor. After the mask, some electrons are scattered while other pass through un-affected. After exiting the bunch compressor, those electrons that were not affected by the slits will appear as short electron bunches. The key advantage of our scheme is its simplicity, tunability and low cost. The scheme does not require any additional hardware such as lasers, undulator, transverse deflecting cavity. The tuning variable is only the RF-chirp and detection of the bunching requires just a skew quad in the chicane and a transverse screen downstream. A thermal analysis suggests that MHz operation of the linac can be sustained under certain beam conditions without any damage to the slit mask.  
 
MOPP059 Study and Design of the High Power RF Coupler for the CH-Cavity of the Fair pLINAC 187
 
  • F. Maimone, G. Clemente, W. Vinzenz
    GSI, Darmstadt, Germany
  
  At GSI a proton Linac has been designed and developed in order to provide a 70 MeV proton beam for the FAIR facility. The pLINAC consists of an RFQ followed by six CH-DTL accelerating cavities and the electromagnetic field inside each cavity is generated by seven Klystrons providing up to 2.8 MW power at 325.224 MHz. The high power RF coupling between the Klystron and the accelerating CH-cavity has been studied and an inductive coupling loop has been designed. The coupler insertion inside the cavity and the rotation angle with respect to the magnetic field lines have been adjusted and the results of the analysis of the coupler positioning are presented. A prototype coupler is under construction and the measurement of RF coupling with the CH-cavity is scheduled within this year.  
 
MOPP060 Status of the GSI Poststripper - HE-Linac 190
 
  • S. Mickat, W.A. Barth, G. Clemente, X. Du, L. Groening, A. Orzhekhovskaya, B. Schlitt, H. Vormann, C. Xiao, S.G. Yaramyshev
    GSI, Darmstadt, Germany
  • M. Droba, H. Hähnel, U. Ratzinger, R. Tiede
    IAP, Frankfurt am Main, Germany
  
  The High-Energy (HE) Linac is proposed to substitute the existing UNILAC post-stripper section. The post-stripper is an Alvarez DTL, which is in operation over four decades successfully. A quasi Front-to-End simulation along the UNILAC shows, that by taking future upgrade options into account already, with the existing Alvarez section the Fair requirements are not reached. Even by substituting the Alvarez section by the HE Linac the aim is not reached per se regarding the existing boundary conditions. Currently workpackages are defined together with the Institute of Applied Physics at Frankfurt University. Starting from the Ion sources to the SIS18 transfer channel every section is reinvestigated for improvements in beam quality and intensity.  
 
MOPP061 First RF Measurements of the Superconducting 217 MHz CH Cavity for the CW Demonstrator at GSI 193
 
  • F.D. Dziuba, M. Amberg, M. Basten, M. Busch, H. Podlech, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • M. Amberg, K. Aulenbacher, W.A. Barth, S. Mickat
    HIM, Mainz, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  • W.A. Barth, S. Mickat
    GSI, Darmstadt, Germany
  
  Funding: Work supported by GSI, HIM, BMBF Contr. No. 05P12RFRBL
Presently, a superconducting (sc) 217 MHz Crossbar-Hmode (CH) cavity is under construction at Research Instruments (RI), Bergisch Gladbach, Germany. Among the horizontal cryomodule and two sc 9.5 T solenoids the cavity is the key component of the cw demonstrator at GSI. To show the operation ability of sc CH cavity technology under a realistic linear accelerator environment is one major goal of the demonstrator project. A successful beam operation of the demonstrator will be a milestone regarding the continuing advanced sc cw linac project at GSI for a competitive production of Super Heavy Elements (SHE) in the future. The fabrication status as well as first rf measurements at room temperature of the 217 MHz CH cavity are presented. 		 
poster icon Poster MOPP061 [1.741 MB]  
 
MOPP062 Proposal of a Conventional Matching Section as an Alternative to the Existing HSI MEBT Superlens at GSI UNILAC 196
 
  • H. Hähnel, U. Ratzinger, R. Tiede
    IAP, Frankfurt am Main, Germany
  
  We propose a new design for the HSI MEBT section at GSI UNILAC as part of the planned UNILAC upgrade. The existing MEBT section was designed in 1996 and based on a novel concept called the superlens* which uses a magnetic quadrupol doublet lens combined with a short RFQ cavity for transversal and longitudinal focusing. In 2009 the RFQ section in front of the MEBT was upgraded which led to significant changes in the RFQ output particle distribution. Recent LORASR simulations show that the superlens transmission decreases to 90% (related to 20.75 mA, U4+ at input). Moreover, the matching to the following IH-DTL is not ideal. This leads to further losses in the IH and to a decrease of the overall UNILAC efficiency. To reach the FAIR requirement of 18 mA U4+ current for the UNILAC with minimal losses and to provide more flexibility for varying current level operation, a new design based on two magnetic quadrupole triplet lenses and a 2-gap buncher is proposed. The design shows full transmission at 20.75 mA U4+ current and improved matching to the IH-DTL, leading to a drastic decrease of particle losses along the IH-DTL.
* U. Ratzinger, R. Tiede, A New Matcher Type between RFQ and IH-DTL for the GSI High Current Heavy Ion Prestripper LINAC, Proc. LINAC96, Geneva, Switzerland, pp. 128-130 		 
poster icon Poster MOPP062 [9.440 MB]  
 
MOPP063 Development of a Pepper Pot Emittance Measurement Device for FRANZ 199
 
  • B. Klump, U. Ratzinger, W. Schweizer, K. Volk
    IAP, Frankfurt am Main, Germany
  
  Funding: This work is supported by HGS-HIRe
Within the FRANZ project [*] on the Institute of Applied Physics, University Frankfurt, a robust and simple pepper pot emittance measurement device for high beam power densities is developed. To use the device directly behind the ion source, a high robustness against HV breakdowns is necessary. This paper gives an overview on experimental setup, on the analysis method and on imaging properties of the screen. Furthermore, the implemented software-based evaluation method is shown. It concludes with a preliminary emittance measurement on the high current ion source for FRANZ.
[*] U. Ratzinger et al., “intense Pulsed Neutron Source FRANZ in the 1-500 keV Range“, Proc. ICANS-XVIII, Dongguan, April 2007, p.210
 		 
 
MOPP064 R&D of the 17 MeV MYRRHA Injector 202
SUPG010   use link to see paper's listing under its alternate paper code  
 
  • D. Mäder, M. Basten, D. Koser, H.C. Lenz, N.F. Petry, H. Podlech, A. Schempp, M. Schwarz, M. Vossberg
    IAP, Frankfurt am Main, Germany
  • C. Zhang
    GSI, Darmstadt, Germany
  
  Funding: Project supported by the EU, FP7 MAX, Contract No. 269565
MYRRHA is designed as an accelerator driven system (ADS) for transmutation of long-lived radioactive waste. The challenge of the linac development is the very high reliability of the accelerator to limit the thermal stress inside the reactor. With the concept of parallel redundancy the injector will supply a cw proton beam with 4 mA and 17 MeV to the main linac. The new MYRRHA injector layout consists of a very robust beam dynamics design with low emittance growth rates. Sufficient drift space provides plenty room for diagnostic elements and increases the mountability. Behind a 4-Rod-RFQ and a pair of two-gap QWR rebunchers at 1.5 MeV the protons are matched into the CH cavity section. A focussing triplet between the rebunchers ensures an ideal transversal matching into the doublet lattice. Each of the 7 RT CH structures has a constant phase profile and does not exceed thermal losses of 29 kW/m. The transition to the 5 SC CH cavities with constant beta profile is at 5.9 MeV. For a safe operation of the niobium resonators the electric and magnetic peak fields are defined below 25 MV/m and 57 mT respectively. 		 
poster icon Poster MOPP064 [4.024 MB]  
 
MOPP065 Investigations of Space-Charge Compensation in Low-Energy Beam Transport (LEBT) Sections Using a Particle-in-Cell Code 205
 
  • D. Noll, M. Droba, O. Meusel, U. Ratzinger, K. Schulte, C. Wiesner
    IAP, Frankfurt am Main, Germany
  
  Among the advantages of magnetostatic LEBT sections is the possibility for compensation of space charge by electrons in the case of positively charged ion beams. In the past, it has been shown that the distribution of these compensation electrons can lead to unwanted emittance growth. However, the distribution of electrons especially in the presence of the magnetic fields of the focussing lenses is difficult to predict. To improve the understanding of the influence on the beam, models for the relevant processes namely residual gas ionization using realistic cross sections as well as secondary electron production on surfaces have been implemented in a particle-in-cell code. In this contribution, we will present the code used as well as first results for two model systems as an example.  
 
MOPP066 High Gradient CH-Type Cavity Development for 10 – 100 AMeV Beams 208
 
  • A. Almomani, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  Funding: This work is supported by Federal Ministry of Education and Research - BMBF No. 05P12RFRB9.
The development in pulsed linac activities aims on compact designs and on an increase of the voltage gain per meter. At IAP - Frankfurt, a CH design was developed for these studies, where the mean effective accelerating field is expected to reach well above 10 MV/m at 325 MHz, β=0.164. Within a funded project, this cavity is systematically developed. Currently, the cavity is under construction at NTG GmbH and expected to be ready for copper plating in autumn 2014. The results should give an impact on the rebuilt of the UNILAC - Alvarez section, optimized for achieving the beam intensities specified for the GSI – FAIR project. A mid- and long- term aim is a compact pulsed high current linac. The new GSI 3 MW Thales klystron test stand will be very important for these investigations. Detailed studies on two different types of copper plating can be performed on this cavity. Additionally, operating of normal conducting cavities at cryogenic temperatures will be discussed. In this work, the cavity status will be presented. 		 
 
MOPP067 Operation of the LINAC and the LINAC RF System for the Ion-Beam Therapy Center Heidelberg 211
MOPOL05   use link to see paper's listing under its alternate paper code  
 
  • E. Feldmeier, R. Cee, Th. Haberer
    HIT, Heidelberg, Germany
  
  The Heidelberg Ion Therapy Center HIT is in clinical operation since 2009. It is the first dedicated european particle accelerator for medical treatment. Its central location on the campus of the Heidelberg University Hospital fits perfectly in the clinical everyday life. The accelerator complex consists of a linear accelerator and a synchrotron and is designed for protons and carbon ions, but can also provide helium and oxygen ions. The LINAC, build in 2006, operates since 5 years in a 24/7 schema which leads to 60000 operating hours up to now. The performance with an availibility of better than 99% is much higher than expected and is caused by a solid design and a well planned and foresighted maintenance. Unavoidable failures during operation can be solved very fast with the on site experts for each section. The combination of personnel spare parts and permanent ongoing developments is very successful. An upgrade program for parts of the linac and also for the RF system is in planning to keep the uptime high and to improve the performance for further needs.  
 
MOPP068 The Fast Piezo-Based Frequency Tuner for SC CH-Cavities 214
 
  • M. Amberg, M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher
    HIM, Mainz, Germany
  • W.A. Barth, V. Gettmann, S. Mickat
    GSI, Darmstadt, Germany
  
  Funding: Work supported by HIM, GSI, BMBF Contr. No 05P12RFRBL
Superconducting structures are very susceptible to external influences due to their thin walls and their narrow bandwidth. Even small mechanical deformations caused by dynamic effects like microphonic noise, pressure fluctuations of the liquid helium bath or Lorentz-Force-Detuning can lead to resonance frequency changes of the cavity which are much larger than the bandwidth. To compensate the slow and fast resonance frequency variations during operation a compact frequency tuner prototype equipped with a stepper motor and a piezo actuator has been developed at the Institute for Applied Physics (IAP) of Frankfurt University. In this paper, the tuner design and the results of first room temperature measurements of the tuner prototype are presented. 		 
poster icon Poster MOPP068 [2.304 MB]  
 
MOPP070 Final Design for the BERLinPro Main Linac Cavity 217
 
  • A. Neumann, J. Knobloch
    HZB, Berlin, Germany
  • K. Brackebusch, T. Flisgen, T. Galek, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  • B. Riemann, T. Weis
    DELTA, Dortmund, Germany
  
  Funding: This work is partly funded by BMBF contract no. 05K10PEA and 05K10HRC
The Berlin Energy Recovery Linac Project (BERLinPro) is designed to develop and demonstrate CW LINAC technology for 100-mA-class ERLs. High-current operation requires an effective damping of higher-order modes (HOMs) of the 1.3 GHz main-linac cavities. We have studied elliptical 7-cell cavities based on a modified Cornell ERL design combined with JLab's waveguide HOM damping approach. This paper will summarize the final optimization of the end-cell tuning for minimum external Q of the HOMs, coupler kick calculations of the single TTF fundamental power coupler as well as multipole expansion analysis of the given modes and a discussion on operational aspects. 		 
poster icon Poster MOPP070 [1.561 MB]  
 
MOPP071 BESSY VSR 1.5 GHz Cavity Design and Considerations on Waveguide Damping 221
 
  • A.V. Velez, J. Knobloch, A. Neumann
    HZB, Berlin, Germany
  
  The BESSY VSR upgrade of the BESSY II light source represents a novel approach to simultaneously store long (ca. 15ps) and short (ca. 1.5ps) bunches in the storage ring with the present user optics. To this end, new high-voltage L-Band superconducting multi-cell cavities must be installed in one of the straights of the ring. These 1.5 GHz and 1.75 GHz cavities are based on 1.3 GHz systems being developed for the BERLinPro energy-recovery linac. This paper describes the baseline electromagnetic design of the first 5-cell cavity operating at 1.5 GHz.  
poster icon Poster MOPP071 [1.088 MB]  
 
MOPP072 Present Status of J-PARC LINAC LLRF Systems 224
 
  • Z. Fang, Y. Fukui, K. Futatsukawa, T. Kobayashi, S. Michizono
    KEK, Ibaraki, Japan
  • E. Chishiro, F. Sato, S. Shinozaki
    JAEA/J-PARC, Tokai-mura, Japan
  
  The RF control systems have been developed for the J-PARC proton linac, which consists of 324-MHz and 972-MHz acceleration sections. From October 2006, we started the commissioning of the 324-MHz sections. Then the J-PARC 324-MHz 181-MeV proton linac had been operated nearly for 7 years, until May 2013. In the summer of 2013, we upgraded the J-PARC linac by adding 972-MHz acceleration sections. The output energy of the J-PARC linac was successfully upgraded to 400 MeV in December 2013, and then the operation of the J-PARC 400-MeV linac started. In the past 8 years of the J-PARC linac operation, no heavy troubles occurred in the RF control systems. Every year we made improvements on the RF control systems, according to the operation experiences. In this paper, the present status of the J-PARC 400-MeV linac RF control systems will be described in details, and an improvement plan for the LLRF systems in the future will also be introduced.  
 
MOPP074 Digital Filters Used for Digital Feedback System at cERL 227
 
  • F. Qiu, D.A. Arakawa, H. Katagiri, H. Matsumoto, S. Michizono, T. Miura
    KEK, Ibaraki, Japan
  
  As a test facility for the future KEK 3-GeV energy recovery linac (ERL) project, the compact ERL (cERL) features three two-cell cavities for the injector and two nine-cell cavities for the main linac. Digital low-level radio frequency (LLRF) systems have been developed to realize highly accurate RF control. In order to reduce the influence of clock jitter and to suppress the parasitic modes in the multi-cell cavities, we have developed several types of digital filters, including a first-order IIR filter, a fourth-order conjugate poles IIR filter and a notch filter. Furthermore, to design a more effective and robust controller (such as an H-infinite controller, or repetitive controller), we need to acquire more detailed system knowledge. This knowledge can be gained by using modern system identification methods. In this paper, we present the latest applications in the LLRF systems of the cERL. identification methods. In this paper, we have compared the performance of these different type filters in cERL. The preliminary result of the system identification will be also described.  
 
MOPP076 Construction of an Accelerator-based BNCT Facility at yhe Ibaraki Neutron Medical Research Center 230
 
  • M. Yoshioka, H. Kobayashi, T. Kurihara, S.-I. Kurokawa, H. Matsumoto, N. Matsumoto
    KEK, Ibaraki, Japan
  • T. Hashirano, T. Sugano
    MHI, Hiroshima, Japan
  • F. Hiraga
    Hokkaido University, Sapporo, Japan
  • H. Kumada, Su. Tanaka
    Tsukuba University, Graduate School of Comprehensive Human Sciences, Ibaraki, Japan
  • A. Matsumura, H. Sakurai
    Tsukuba University, Ibaraki, Japan
  • N. Nagura, T. Ohba
    Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan
  • T.N. Nakamoto, T. Zagar
    Cosylab, Ljubljana, Slovenia
  • T. Nakamura
    JAEA, Ibaraki-ken, Japan
  • T. Ouchi
    ATOX, Ibaraki, Japan
  
  An accelerator-based BNCT (Boron Neutron Capture Therapy) facility is being constructed at the Ibaraki Neutron Medical Research Center. It consists of a proton linac of 80kW beam power with 8 MeV energy and 10mA average current, a beryllium target, and a moderator system to provide an epi-thermal neutron flux enough for patient treatment. The technology choices for this present system were driven by the need to site the facility in a hospital and where low residual activity is essential. The maximum neutron energy produced from an 8 MeV-proton is 6 MeV, which is below the threshold energy of the main nuclear reactions which produce radioactive products. The down side of this technology choice is that it produces a high density heat load on the target so that cooling and hydrogen aniti-blistering amelioration prevent sever challenges requiring successful R&D progress. The latest design of the target and moderator system shows that a flux of 4×109 epi-thermal neutrons / cm2 / sec can be obtained. This is much higher than the flux from the existing nuclear reactor based BNCT facility at JAEA ( JRR-4).  
 
MOPP077 Electron-Driven Positron Capture Simulation for ILC 233
 
  • Y. Seimiya, M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • T. Okugi, T. Omori, M. Satoh, J. Urakawa
    KEK, Ibaraki, Japan
  • T. Takahashi
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
  
  ILC (International Linear Collider) is a next high-energy physics project to study the Higgs property as detail as possible and new phenomena beyond standard model. In ILC, the positron beam is produced by converting gamma rays from undulator radiations. To obtain gamma rays as undulator radiation, the electron beam for collision (150 GeV or more) is used. This positron generation scheme is a totally new approach. From project point of view, it is desirable to have a technical backup as a replacement of the undulator scheme. We propose an ILC positron source based on the conventional electron driven scheme. In this scheme, positron beam is generated from electromagnetic shower in a heavy target material where electron beam is injected. By manipulating the beam time structure to relax the heat load on the production target, the scheme can be feasible technically. In this study, positron capture in the electron driven scheme is simulated from the positron production to the positron damping ring, to demonstrate that an enough amount of positron can be generated and captured with a controllable heat load on the target.  
poster icon Poster MOPP077 [0.879 MB]  
 
MOPP078 RF Power Systems for the FAIR Proton Linac 236
 
  • J. Lesrel, C. Joly
    IPN, Orsay, France
  • E. Plechov, A. Schnase, G. Schreiber, W. Vinzenz
    GSI, Darmstadt, Germany
  
  In the framework of collaboration between the FAIR project, GSI, and CNRS, the IPNO lab is in charge of providing the high power RF components for a cavity test stand and for the planned FAIR proton Linac. This Linac will be connected to the existing GSI synchrotron SIS18 for serving as an injector for the new FAIR facility. The 70 MeV FAIR proton Linac design contains a 3 MeV RFQ, and a DTL based on Cross-bar H-mode cavities (CH). It will operate with pulsed RF at 325.224 MHz with a width of 200 μs and a repetition rate of 4 Hz. The planned RF systems of the proton Linac will be presented as well as the description of the test stand. The first power test results are obtained with a Thales klystron developed jointly with CNRS. Three solid state amplifiers made by Sigmaphi Electronics for the bunchers will also be described in this paper.  
 
MOPP080 Beam Dynamics Study for RAON Superconducting Linac 239
 
  • H. Jang, H.J. Kim
    IBS, Daejeon, Republic of Korea
  • J.G. Hwang
    KNU, Deagu, Republic of Korea
  • B.H. Oh
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  
  Rare Isotope Science Project (RISP) in Korea is going to build an ion accelerator, RAON which can generate and accelerate various stable ions such as uranium, proton, xenon and rare isotopes such as tin, nickel. Linear accelerators of RAON adopted superconducting RF cavities and warm quadruple doublet structure. In RAON, there are two low energy linacs which can accelerate the Uranium beam from 0.5MeV/u to 17.5MeV/u, charge stripping sections and one high energy linac which can accelerate the Uranium beam up to 200MeV/u. Due to the diversity of planned ions and isotopes, their A/q range lies widely from 1 to 8. As a result, the research related with linac lattice design and beam dynamics is one of the important topics to build RAON. In this presentation the current status of RAON linac lattice design and the beam dynamics simulation results for acceleration of various ions will be described.  
 
MOPP081 The ECT System for RAON's Cavities 242
 
  • M.J. Joung, Y. Jung, H.J. Kim
    IBS, Daejeon, Republic of Korea
  
  The ECT system is in use for Nb surface control in many laboratories. This system can inspect Nb surface quickly using high resolution. The ECT system for RAON's cavity was made with the feature : It has 3-axis acting probe movement system, It can inspect big size of Nb sheet, which is 1m by 1m and It contain the analysis program that can show the result as 2D and 3D image as well as relative figure of surface level. The standard sample was made with various sizes of defects using the same Nb sheet that was used to make RISP cavity. The ECT system conditioining was carried out to optimize ECT operation on the frequency, the range is from 300kHz to 2MHz. The result of 900 kHz shows the strongest signal. The conditioning experiment on other parameter will be carried out in near future. .  
 
MOPP082 Superconducting Linac for RISP 245
 
  • H.J. Kim, H.J. Cha, M.O. Hyun, H.C. Jung, Y.J.K. Kim, M. Lee
    IBS, Daejeon, Republic of Korea
  
  The RISP (Rare Isotope Science Project) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. It can deliver ions from proton to Uranium. Proton and Uranium beams are accelerated upto 600 MeV and 200 MeV/u respectively. The facility consists of three superconducting linacs of which superconducting cavities are independently phased. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the RISP linac design, the prototyping of superconducting cavity and cryomodule.  
 
MOPP083 Helical Waveguides for Short Wavelength Accelerators and RF Undulators 248
 
  • S.V. Kuzikov, A.V. Savilov, A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  • A.V. Savilov
    NNGU, Nizhny Novgorod, Russia
  
  The short wavelength accelerating structure can combine properties of a linear accelerator and a damping ring simultaneously. It provides acceleration of straight on-axis beam as well as cooling of this beam due to the synchrotron radiation of particles. These properties are provided by specific slow eigen mode which consists of two partial waves, TM01 and TM11. The flying RF undulator introduces a high-power short pulse, propagating in a long helically corrugated waveguide where the -1st space harmonic with negative phase velocity is responsible for particle wiggling. High group velocity allows providing long interaction of particles with RF pulse. Calculations show that RF undulator with period 5 mm, undulator parameter 0.1 is possible in 1 GW 10 ns pulse at frequency 30 GHz. The eigen mode in a helical undulator might have 0th harmonic phase velocity equal to light velocity. Such wave can be excited by relativistic drive bunch in the waveguide where witness bunch follows after the drive bunch, wiggles in wakefields, and generates X-rays at whole waveguide length. Helical waveguides can also be used in order to channel low-energy bunches in RF undulator of THz FEL.  
poster icon Poster MOPP083 [2.139 MB]  
 
MOPP084 Nondestructive Diagnostics of Proton Beam Halo and Transverse Bunch Position by Cerenkov Slow Wave Structures 251
MOPOL08   use link to see paper's listing under its alternate paper code  
 
  • S.V. Kuzikov, M.B. Goykhman, A.V. Gromov, A.V. Palitsin, Yu.V. Rodin, A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  
  An appearance of the halo around bunch of particles is very undesirable destructive phenomenon in high-intensity proton accelerators. We suggest using built-in short BWO section in form of the corrugated metallic waveguide, in order to control particle distribution in real time. In BWO low velocity proton bunch has synchronism with slow spatial harmonic of TM01 wave. Fields of slow harmonic sharply grow in direction from axis to walls and rf power, generated by flying bunch of the given charge, critically depends on transverse bunch size. Results of the simulation, carried out for 20 pC proton bunch of 10 ps duration, show that in 5 GHz BWO of 30 cm length the output rf pulse of several nanosecond duration is varied from mW- level (for 1 mm transverse bunch size) to several tens of mW (for bunch of 20 mm radius). This power level is high enough to control halo appearance in each single proton bunch. The producible rf power in a BWO is also dependent on bunch deflection from axis. This effect we plan to use, in order to provide transverse bunch position monitoring by means of two additional rectangular slow wave section which have corrugations on mutually perpendicular walls.  
poster icon Poster MOPP084 [0.732 MB]  
 
MOPP086 Ecr Ion Sources Developments at INFN-LNS for the Production of High Brightness Highly Charged Ion Beams 254
 
  • D. Mascali, C. Altana, L. Andò, C. Caliri, G. Castro, L. Celona, S. Gammino, L. Neri, F.P. Romano, G. Torrisi
    INFN/LNS, Catania, Italy
  • G. Sorbello
    University of Catania, Catania, Italy
  
  The design of future high-performing ECRIS will require alternative approaches in microwave-to-plasma coupling, in order to maximize the electron density at relatively low frequency and reduce the super-hot electrons formation and their consequences on the beam stability and on source reliability. On these purposes, different activities have been carried out at INFN-LNS in the recent past, including advanced modelling, diagnostics, and studies about alternative methods of plasma heating based on electrostatic-waves generation. A description of these activities will be presented, with special emphasis to the microwave to plasma coupling and to the plasma diagnostics. Some of the already collected results have been a basis for the design of the new AISHa source (for hadrontherapy purposes) and the construction of the innovative prototype named Flexible Plasma Trap: on this machine we will search for advanced schemes of microwave launching, now ongoing thanks to full-wave plus kinetic calculations of the wave-to-plasma interaction mechanism  
 
MOPP087 Construction of the Modules of the IFMIF-EVEDA RFQ 257
 
  • A. Pepato, E. Fagotti, F. Grespan, A. Palmieri, A. Pisent, C. R. Roncolato
    INFN/LNL, Legnaro (PD), Italy
  • R. Dima, L. Ferrari, E. Udup
    INFN- Sez. di Padova, Padova, Italy
  • A. Margotti
    INFN-Bologna, Bologna, Italy
  • P. Mereu
    INFN-Torino, Torino, Italy
  
  The IFMIF project aims to produce an intense neutron flux to test and qualify materials suitable for the construction of fusion power plants. We are working on the engineering validation phase of the project, which consists on the construction of a linear accelerator prototype to be installed and commissioned in Rokkasho. The RFQ is composed of 18 modules flanged together for a total length of 9.8m designed to accelerate the 125mA D+ beam to 5MeV at a frequency of 175MHz. The mechanical specifications are very challenging, tight tolerances are required on the machining and on the brazing process. The line is subdivided into 3 Super Modules of 6 modules each. The production of the High Energy portion has been completed and delivered, while the Low Energy one is performing the acceptance test. They were commissioned to external firms. The production of the Intermediate Energy portion has been done in house (INFN) and will be commissioned soon. The 1st modules (16, 17 and 2) were produced adopting 2 brazing steps, while for all the remaining ones we adopted a single brazing step. In this paper the production status and the development of the brazing procedure will be described.  
 
MOPP088 MUNES a Compact Neutron Source for BNCT and Radioactive Wastes Characterization 261
 
  • A. Pisent, P. Colautti, E. Fagotti
    INFN/LNL, Legnaro (PD), Italy
  
  At INFN LNL (Legnaro Italy) it has been built a high intensity Radio Frequency Quadrupole (RFQ) structure, able to produce a 5 MeV proton beam of 30 mA. Coupled with a Be target such a beam can generate a neutron flux of 1014 n/s, with a spectrum centered in the MeV region (that has been recently characterized in detail at LNL accelerators). This neutron flux can be moderated to generate a thermal or epithermal source for BNCT with very little contamination of energetic form energetic neutron and gamma. Since the approval of MUNES project (in 2012) the high technology issues related to a compact neutron source to be installed in an Hospital environment have been faced. In particular for the powering of the accelerating structure an innovative system, completely based on solid state amplifiers, has been developed and ordered to industry. An outline of MUNES design and the status of the project will be given in the paper.  
 
MOPP090 Adjustment of the Coupling Factor of the Input Coupler of the ACS Linac by a Capacitive Iris in J-PARC 264
 
  • J. Tamura, H. Ao, K. Hirano, Y. Nemoto, N. Ouchi
    JAEA/J-PARC, Tokai-mura, Japan
  • H. Asano
    Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan
  • F. Naito, K. Takata
    KEK, Ibaraki, Japan
  
  Annular-ring Coupled Structure (ACS) cavities have been installed to increase the beam energy of the Japan Proton Accelerator Research Complex (J-PARC) linac from 181 to 400 MeV in the maintenance period of 2013. Some of the pillbox type input couplers with a ceramic window to the ACS cavity have a larger coupling factor than the target value by an avoidable manufacturing error. To adjust the coupling factor, a capacitive iris was introduced in the rectangular waveguide near the coupler. As a result, it has been confirmed that the iris decreases the coupling factor to a target value without any significant increase in temperature and in a discharge rate during high-power operation. In this paper, the design procedure of the capacitive iris and the result of the coupling factor adjustment are presented.  
 
MOPP091 Beam Test of a New RFQ for the J-PARC Linac 267
 
  • Y. Kondo, T. Morishita, Y. Sawabe, S. Yamazaki
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • T. Hori
    JAEA, Ibaraki-ken, Japan
  • A. Takagi
    KEK, Ibaraki, Japan
  
  We performed a beam test of a new 324-MHz 3-MeV RFQ (RFQ III) for the beam-current upgrade of the J-PARC linac. RFQ III is the first RFQ developed to meet the requirement of the J-PARC linac. The peak beam current is 50mA, pulse length is 500 micro-sec, and the repetition is 25 Hz. Before the installation to the accelerator tunnel scheduled in summer of 2014, we built a test stand for offline testing of the new ion source and RFQ. Basic performances of RFQ III such as transmission, transverse emittance, and energy spread were measured with short pulse length beams. In this paper, we present the results of the beam test.  
 
MOPP092 Compact Timing System with FPGA for SPring-8 Linac 270
 
  • H. Dewa, H. Hanaki, S. Suzuki
    JASRI/SPring-8, Hyogo-ken, Japan
  
  Funding: This reserch was supported by TAKUMI project.
A new timing system for SPring-8 linac was developed. It is a test system to confirm the possibility of replacing the current NIM module-based system. Although fast logic circuits can be made easily with NIM modules, they become complicated when they are used in a large system. The timing system for SPring-8 linac has been getting larger and larger after several improvements for injection to New SUBARU (NS), top-up injection for storage ring, low repetition operation for saving energy, fast alternative injection and so on. In order to simplify the system, we adopted FPGA technology that can run at a clock over 500 MHz. The new system has 50 NIM inputs and outputs on the front panel, which is installed in an 8U rack-mount box. It only has gun trigger parts of current system, but includes all of the circuit components used in the current system such as and/or logics, counter delay, fan in/out etc. Three clock sources for Synchrotron injection, NS injection, and linac solo use are available in the FPGA, and they can be changed rapidly according to the trigger sources. We describe here the details of test timing system, the results of timing jitter measurements. 		 
 
MOPP093 Evaluation of Beam Energy Fluctuations Caused by Phase Noises 273
 
  • H. Hanaki, H. Dewa, S. Suzuki, K. Yanagida
    JASRI/SPring-8, Hyogo-ken, Japan
  • T. Asaka, T. Ohshima
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  
  The SSB noises of the RF reference signal dominate the short-term instabilities of the RF phase of the carrier RF. This phase modulation finally results in beam energy fluctuation. This presentation gives a quantitative evaluation of the beam energy fluctuations in an electron linear accelerator caused by phase noises, comparing a theoretical analysis and experimental results. A simple model was introduced to understand how phase noises result in the relative phase difference between a beam bunch and accelerating RF fields. In the experiments, we measured the enhanced beam energy fluctuations by modulating the phase of the reference RF signals with an external signal. The interference between the accelerating RF phase modulation and the timing modulation of a beam bunch was found in the model analysis and also in the experimental results.  
 
MOPP094 Latest Improvements of the SPring-8 Linac for High Reliability 276
 
  • S. Suzuki, H. Dewa, H. Hanaki, T. Kobayashi, T. Magome, A. Mizuno, T. Taniuchi, K. Yanagida
    JASRI/SPring-8, Hyogo-ken, Japan
  • T. Asaka
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  
  In order to perform stable injection to the 8GeV SPring-8 storage ring, which is performing the top-up operation, the high reliability of the linac has been advanced as follows: For reduction of phase variations caused by the waveguide deformation due to the variations of temperature or atmospheric pressure, the waveguide circuit of SF6 enclosure type, which fed RF powers to the bunching section, was replaced with that of vacuum type. And S-band 10MW circulators and isolators of vacuum type were adopted for the first time in the world. The timing system was improved so that the interval time of the beam injection into the 8GeV booster synchrotron and the 1.5 GeV NewSUBARU storage ring has been reduced to 1 sec from 15 seconds, respectively, even in the top-up operation of both storage rings. As a result, the stored current by the top-up operation were further stabilized. The stored current of the NewSUBARU storage ring was stabilized to 0.18% from 0.31%. The electron gun cathode assembly has been developed to reduce the dark emission from a grid plate by the double grid method and the electrolytic polishing.  
 
MOPP095 Emittance Measurement for SPring-8 Linac Using Four Six-Electrode BPMs 279
MOPOL09   use link to see paper's listing under its alternate paper code  
 
  • K. Yanagida, H. Hanaki, S. Suzuki
    JASRI/SPring-8, Hyogo-ken, Japan
  
  In the SPring-8 linear accelerator (linac) six-electrode beam position monitors (BPMs) have been installed to measure second-order moments. At the end of the linac where the electron beam energy is 1 GeV four quadrupole magnets are utilized for twiss parameter matching toward the following beam transport line. Last year four six-electrode BPMs were installed at the locations of these four quadrupole magnets for an emittance measurement. The relative second-order moments were obtained changing the magnetic field strength of the quadrupole magnets, then beam sizes, emittances and twiss parameters were deduced or calculated. At this time we applied one pair of beam sizes measured by the screen monitor for a precise determination of emittances but we try to implement non-destructive measurement with no screen monitor. Before the emittance measurement a calibration with fifth-order moment correction was carried out changing beam positions at the BPM locations using upstream steering magnets (the entire calibration).  
slides icon Slides MOPP095 [0.984 MB]  
 
MOPP096 Current Status of the Mainz Energy-Recovering Superconducting Accelerator Project 282
 
  • M. Dehn, I. Alexander, K. Aulenbacher, J. Diefenbach, R.G. Heine, C. Matejcek, F. Schlander, D. Simon
    IKP, Mainz, Germany
  
  Funding: Work supported by the German Federal Ministery of Education and Research (BMBF) and German Research Foundation (DFG) under the Cluster of Excellence "PRISMA"
The Mainz Energy-Recovering Superconducting Accelerator (MESA) project at Johannes Gutenberg-Universtitaet Mainz has started in 2012 and is in full swing now. This presentation shows the current status of the project with a glance on cryogenics, superconducting RF, accelerator lattice design and the normal conducting injector. 		 
 
MOPP097 The Physics Programme of Next MICE Step IV 285
 
  • V. Blackmore
    JAI, Oxford, United Kingdom
  
  Funding: DOE, NSF, STFC, INFN and more
The international Muon Ionisation Cooling Experiment (MICE) is progressing toward a full demonstration of the feasibility of the cooling technology required for neutrino physics and muon colliders. Step IV will provide the first precise measurements of emittance and determine the influence of material properties on emittance reduction. The physics programme of the Step IV measurements is described in detail, along with a longer term view to demonstrating and studying (sustainable) ionisation cooling with re-acceleration.
The abstract is submitted by the chair of the MICE Speakers Bureau.
The presentation will be delivered by Dr Victoria Blackmore (Oxford)
Promotion to Oral presentation is be most welcome. 		 
 
MOPP098 Physical Starting of the First and Second Section of Accelerator Linac-800 288
 
  • V. Kobets, N. Balalykin, I.N. Meshkov, V. Minashkin, G. Shirkov
    JINR, Dubna, Moscow Region, Russia
  • V. Shabratov
    JINR/VBLHEP, Moscow, Russia
  
  In the report discusses the modernization of linear electron accelerator MEA (Medium Energy Accelerator). The aim is to develop a set of MEAs based free-electron lasers, imposed a number of emission wavelengths from infrared to ultraviolet. In work presents the results of the physical starting of the first and second stations accelerating electron linear accelerator LINAC-800, as well as start infrared undulator. We discuss the work program for this accelerator.  
 
MOPP099 Compact Proton Injector for Synchrotrons 291
 
  • A.D. Kovalenko, A.V. Butenko
    JINR, Dubna, Moscow Region, Russia
  • A. Kolomiets, A.S. Plastun
    ITEP, Moscow, Russia
  
  Compact linac comprising two sections of different RFQ structures was designed. The first section is conventional RFQ with output energy 3 MeV whereas the second one is RFQ with trapezoidal modulation of vanes. The linac output energy is 8 MeV. The both structures operate at frequency of 352 MHz. The total length of machine is less than 8 m. The output pulsed beam current is of 40 mA. The design is suitable for both as NICA injection complex and proton superconducting medical synchrotron.  
 
MOPP100
 Developments of S-band and X-band Compact RF Linear Accelerators for Security and Medical Applications at KAERI  
 
  • Y. Kim, S.S. Cha, B.N. Lee, B.C. Lee, H.D. Park, K.B. Song
    KAERI, Dae-jeon, Republic of Korea
  • P. Buaphad
    ISU, Pocatello, Idaho, USA
  • S.S. Cha
    UST, Daejeon City, Republic of Korea
  
  In 2013, KAERI successfully developed a dual energy (9/6 MeV) S-band electron linear accelerator for the container inspection system. In addition, in 2014, KAERI also developed a 6 MeV X-band linear accelerator for CyberKnife and dual head gantry projects. In this paper, we report our recent successful developments of compact S-band and X-band RF linear accelerators for medical and security applications at KAERI.  
 
MOPP101 Design of the 4MeV RFQ for the Helium Beam Irradiatior 294
 
  • H.-J. Kwon, Y.-S. Cho, H.S. Kim, K.T. Seol, Y.-G. Song
    KAERI, Daejon, Republic of Korea
  
  Funding: This work was supported by the Ministry of Science, ICT & Future Planning of the Korean Government.
A RFQ is considered as a main accelerator of the helium beam irradiation system for the power semiconductor in Korea Multipurpose Accelerator Complex (KOMAC). The RFQ was designed to accelerate the He2+ beam up 4MeV with 10mA peak beam current. We chose a vane type RFQ with 200MHz operating frequency. The RFQ will be operated with the frequency tracking mode supplied by the digital low level rf control system. In this paper, the design of the 4MeV RFQ is presented and the beam irradiation system including rf system, control system, utility system, is discussed. 		 
 
MOPP103 Fault Tolerance and Consequences in the MYRRHA Superconducting Linac 297
 
  • F. Bouly
    LPSC, Grenoble Cedex, France
  • J.-L. Biarrotte
    IPN, Orsay, France
  • D. Uriot
    CEA/DSM/IRFU, France
  
  Funding: This work is being supported by the European Atomic Energy Community’s EURATOM) Seventh Framework Programme under grant agreement n°269565(MAX project).
The MYRRHA project aims at the construction of new irradiation complex in Mol (Belgium) to demonstrate the transmutation feasibility with an Accelerator Driven System (ADS). In its subcritical configuration, the MYRRHA facility requires a proton flux with a maximum power of 2.4 MW (600 MeV - 4 mA). Such a continuous wave beam will be delivered by a superconducting linac which must fulfil very stringent reliability requirements to ensure the safe ADS operation with a high level of availability. In this purpose, the accelerator design is based on a redundant and fault-tolerant scheme to enable rapid failures mitigations. Beam dynamics studies on the fault tolerance capability of the MYRRHA superconducting linac will be presented. The results will be mainly focused on RF failure compensation scenarios: when one or several superconducting cavities are lost in the linac. The impact on the R&D to enable fast retuning procedures in the linac will also be discussed. 		 
 
MOPP104
 Analytical Approach for Life Assessment of Pierce Type Diode Electron Gun in High Energy Electron Linear Accelerator Systems  
 
  • K.K. Rai
    IUAC, New Delhi, India
  • B.K. Bhatt, A. Rai, K.K. Rai
    Linac Systems, LLC, Waxahachie, Texas, USA
  • K.K. Rai, K.K. Rai
    BARC, Mumbai, India
  
  High Energy Electron linacs are used for generation of high energy X Rays towards the protection and development of humanity. Efficiency and life of Linac and, other high power microwave tube like klystrons and magnetrons solely depends upon ruggedness and reliability of the gun. The biggest threat to the vitality of electron gun is the poisoning of the metallic surfaces, other factors like evaporation of key constituents of cathode, geometrical change in cathode structure, quality of HV and LV signals also decisive to determine the life. This paper reveals the performance behavior of electron gun in a life span of 0-10 years is evaluated by the analytical interpretation of huge data collected over the period, for various Magnetron and Klystron based Linacs, of 7,9 and 15 MeV energies. Following parameters are recorded and analyzed almost on daily basis for the period: Reflected Wave, Beam Current, Vacuum current etc. The correlation of the data and the wave shapes has revealed the pattern of gradual decrement in the rate of generation of electrons from the gun in normal case. Abrupt loss of electrons has also detected in case of partial loss of vacuum level in the gun.
Keywords: Thyratron; Perce Type Diode Gun,; Linac; Resonant Cavities; Reflected Wave; Ultra High vacuum.
 		 
 
MOPP106 3D Mode Analysis of Full Tanks in Drift-Tube Linacs 300
 
  • S.S. Kurennoy
    LANL, Los Alamos, New Mexico, USA
  
  Drift-tube linacs (DTLs) are usually designed and analyzed in axisymmetric approximation, cell by cell, using 2D codes such as Superfish and Parmila. We have developed 3D models of full DTL tanks with CST Studio to accurately calculate the tank modes, their sensitivity to post-coupler positions and tilts, tuner effects, and RF-coupler influence. Such models are important for the LANSCE DTL where each of four tanks contains tens of drift tubes and tank 2 has as much as 66 cells. We perform electromagnetic analysis of the DTL tank models using MicroWave Studio (MWS), mainly with eigensolvers but also in time domain. A similar approach has already been applied for thermal analysis of the LANSCE DTL but only with short tank models [1]. The full-tank analysis allows tuning the field profile of the operating mode and adjusting the frequencies of the neighboring modes within a realistic CST model. The MWS-calculated RF fields can be used for beam dynamics and thermal modeling. Here we present beam dynamics results for the LANSCE DTL from Particle Studio.
[1] S.S. Kurennoy, LINAC08, Victoria, BC, 2008, p. 951. 		 
 
MOPP107 Results from the Installation of a New 201 MHz RF System at LANSCE 303
 
  • J.T.M. Lyles, C.L. Arnold, W.C. Barkley, J. Davis, A.C. Naranjo, M.S. Prokop, D. Rees, G. M. Sandoval, Jr.
    LANL, Los Alamos, New Mexico, USA
  • D. Baca, R.E. Bratton, R.D. Summers
    Compa Industries, Inc., Los Alamos, New Mexico, USA
  
  Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396.
The LANSCE RM project is restoring the linac to it’s original high power capability after the power grid tube manufacturer could no longer provide triodes that could consistently meet our power requirements. High duty factor Diacrodes® now supply RF power to the largest DTL tank. These tetrodes reuse the existing infrastructure including water-cooling systems, coaxial transmission lines, high voltage power supplies and capacitor banks. The power amplifier system uses a combined pair of LANL-designed cavity amplifiers using the TH628L Diacrode® to produce as much as 3.5 MW peak and 420 kW of mean power. A digital low level RF control system was developed to complement these new linear amplifiers. Design and testing was completed in 2012, with commercialization following in 2013. The first installation is commissioned. The two remaining high power RF systems for tanks 3 and 4 will be replaced in subsequent years using a hybrid old/new RF system until the changeover is complete. Features and operating results of the replacement system are summarized, along with observations from the rapid-paced installation project. 		 
 
MOPP108 Vertical Electro-Polishing of Nb Nine-Cell Cavity Using Cathode with Variable-Geometry Wings 307
 
  • K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
    KEK, Ibaraki, Japan
  • K. Ishimi
    MGI, Chiba, Japan
  
  Marui Galvanizing Co. Ltd. has been studying on Vertical Electro-Polishing (VEP) of Nb superconducting accelerator cavity for the mass-production and cost-reduction of Electro-Polishing (EP) process in collaboration with KEK. And we invented VEP process by a cathode with variable-geometry wings 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 fabrication of the first VEP facility for Nb nine-cell cavity and the VEP results using cathode with variable-geometry wings.  
 
MOPP109 Ion Beam Acceleration in Neutron Tube 310
 
  • V.I. Rashchikov
    MEPhI, Moscow, Russia
  • A.S. Plastun
    ITEP, Moscow, Russia
  
  Deuteron beam acceleration in ion-optic system of gas-filled neutron tubes was investigated. PIC code SUMA "*" used for computer simulation of ionization and knock on processes and there influence on deuteron beam parameters. When deuteron and ionized particles own space charge forces become the same order of magnitude as external one, virtual cathode may occurs. It is happened because of injected from ion source deuterons cannot overcome their own space charge potential wall and move in transverse direction. However, electrons, produced by ionization, are trapped within the deuteron beam space charge potential wall and decrease it significantly. Thus, space charge neutralization of deuteron beams by electrons, may considerably increase target current and, as a result, output neutron flow. Moreover, own longitudinal electric field rise near the target leads to reduction of accelerating electrode – target potential wall, which was made to prevent knock on emission from the target. As a result, additional knocked on electrons may appear in the region and should be taken into account. The data obtained were compared with experimental results.
* A.N. Didenko, V.I. Rashchikov, V.E. Fortov, Technical Physics, Vol. 56, No. 10,pp. 1535–1538, 2011
 		 
 
MOPP110 Multipacting Prediction for the 106.1 MHz Quarter Wave Resonator 313
 
  • M. Gusarova, I.I. Petrushina, E.A. Savin, A.N. Stolbikova
    MEPhI, Moscow, Russia
  • V. Zvyagintsev
    TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
  
  The results of analytical calculations and numerical simulations of multipacting in the 106.1 MHz Quarter Wave Resonator (QWR) are presented. Resonant voltages, impact energies and corresponding particle trajectories are obtained. In this paper we compare CST PS and MultP-M 3D simulation results for multipacting in the cavity.  
 
MOPP111
 Electrodynamics characteristics coupling cavity RFQ and DTL the heavy ion linear accelerator MILAC  
 
  • A.P. Kobets, V.A. Bomko, O.F. Dyachenko, J.V. Meleshkova, K.V. Pavlij, S.S. Tishkin, B.V. Zajtsev
    NSC/KIPT, Kharkov, Ukraine
  
  New pre-stripping section (PSS-20) the MILAC heavy ion linear accelerator with the relation of their mass to charge A/q=20 is developed That will allow to extend considerably a range accelerating ions and to increase intensity of beams. On an initial part of acceleration of ions from 6 keV/u up to 150 keV/u high capture in process of acceleration of the injected ions is provided interdigital (IH) accelerating structure with Radio-Frequency Quadrupole (RFQ) focusing. On the second part of acceleration of ions from 150 keV/u up to 1 MeV/u the highest rate of acceleration is created interdigital (IH) accelerating structure with drift tubes DTL. Task in view of coupling of such diverse accelerating structures in one resonator. It will allow to simplify considerably manufacturing and operation PSS-20. Effects of researches on optimisation of parametres of the construction providing demanded quantity of operational frequency and electrodynamic characteristics are given. Process of such optimisation was carried out by mathematical modelling, and also by means of experimental researches on model of the coupling cavity.  
 
MOPP112 Beam Dynamics of Multi Charge State Ions in RFQ Linac 317
SUPG015   use link to see paper's listing under its alternate paper code  
 
  • Y. Fuwa, S. Ikeda, M. Kumaki
    RIKEN, Saitama, Japan
  • Y. Fuwa, Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  • T. Kanesue, M. Okamura
    BNL, Upton, Long Island, New York, USA
  
  Laser ion source with DPIS (Direct Plasma Injection Scheme) is a promising candidate for a pre-injector of the high-intensity accelerator. Eliminating LEBT (Low Energy Beam Transport) where the space charge effect is severe, DPIS provides high current ion beam from laser plasma at the entrance of a RFQ linac and ion beams are injected directly into the RFQ linac. However, the injected beam consists of multi charge state ions and their behavior in RFQ linac has not been well understood. In this research, we study the beam dynamics of multi charge state ions in a RFQ. Using the result of computer simulation, a set of 100MHz 4-rod RFQ vanes, which accelerates Al 12+ ion among various charge states of aluminum ions from 8.9 keV/u to 200 keV/u, is newly designed and fabricated to be tested with beams. The result of beam acceleration test using the vane will be reported.  
 
MOPP114 SNS Linac Upgrade Plans for the Second Target Station 320
MOPOL06   use link to see paper's listing under its alternate paper code  
 
  • J. Galambos, D.E. Anderson, M.P. Howell, S.-H. Kim, M.A. Plum, A.P. Shishlo
    ORNL, Oak Ridge, Tennessee, USA
  • M.E. Middendorf
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
The Second Target Station (STS) upgrade for the Spallation Neutron Source (SNS) proposes the addition of a short pulse, long wavelength neutron scattering station. In order to provide world-class intensity at the additional station, the SNS linac beam power capability is doubled, to 2.8 MW. This will be accommodated by a 30% increase in the beam energy to 1.3 GeV and a 50% increase in beam current. The beam energy increase will be provided by the addition of 7 additional cyro-modules and supporting RF equipment in space provided during the original SNS construction. The beam current increase will be provided by improved ion source and a reduced chopping fraction, and will require increases in the RF and high voltage modulator systems to accommodate the additional beam loading. Initial plans will be presented. The proposed linac upgrade path will be described. 		 
 
MOPP115 Plasma Processing of Nb Surfaces for SRF Cavities 323
MOPOL10   use link to see paper's listing under its alternate paper code  
 
  • P.V. Tyagi, M. Doleans, S.-H. Kim
    ORNL, Oak Ridge, Tennessee, USA
  • R. Afanador, C.J. McMahan
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  Funding: This work is supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
Field emission is one of the most critical issues to achieve high performances of niobium (Nb) superconducting radio frequency (SRF) cavities. Field emission is mainly related to contaminants present at top surface of SRF cavities that act as electron emitters at high gradient operation and limit the cavity accelerating gradient. An R&D program at the Spallation Neutron Source (SNS) is in place* aiming to develop an in-situ plasma processing technique to remove some of the residual contaminants from inner surfaces of Nb cavities and improve their performance. The plasma processing R&D has first concentrated on removing hydrocarbon contamination from top surface of SRF cavities. Results from the surface studies on plasma processed Nb samples will be presented in this article and showed the removal of hydrocarbons from Nb surfaces as well as improvement of the surface workfuntion (WF).
*M. Doleans et al. “Plasma processing R&D for the SNS superconducting linac RF cavities” Proceedings of 2013 SRF workshop, Paris, France 		 
slides icon Slides MOPP115 [1.405 MB]  
 
MOPP117 Multipole and Field Uniformity Tailoring of a 750 MHz RF Dipole 326
SUPG020   use link to see paper's listing under its alternate paper code  
 
  • A. Castilla, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • A. Castilla
    DCI-UG, León, Mexico
  • A. Castilla, J.R. Delayen
    JLab, Newport News, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
In recent years great interest has been shown in developing rf structures for beam separation, correction of geometrical degradation on luminosity, and diagnostic applications in both lepton and hadron machines. The rf dipole being a very promising one among all of them. The rf dipole has been tested and proven to have attractive properties that include high shunt impedance, low and balance surface fields, absence of lower order modes and far-spaced higher order modes that simplify their damping scheme. As well as to be a compact and versatile design in a considerable range of frequencies, its fairly simple geometry dependency is suitable both for fabrication and surface treatment. The rf dipole geometry can also be optimized for lowering multipacting risk and multipole tailoring to meet machine specific field uniformity tolerances. In the present work a survey of field uniformities, and multipole contents for a set of 750 MHz rf dipole designs is presented as both a qualitative and quantitative analysis of the inherent flexibility of the structure and its limitations. 		 
 
MOPP118 C-Band Load Development for the High Power Test of the SwissFEL RF Pulse Compressor 329
 
  • A. Citterio, J. Stettler, R. Zennaro
    PSI, Villigen PSI, Switzerland
  
  The SwissFEL C-band Linac will have 26 RF modules, each one consisting of a solid-state modulator and a 50 MW klystron that feeds a pulse compressor and four two meters long accelerating structures. The pulse compressor is of the Barrel Open Cavity type (BOC). A first prototype was successfully produced and high-power tested, reaching for full power klystron operation a peak power of 300 MW. For testing this BOC at maximum RF power, a broadband load was designed and built, based on a ridge waveguide design and high permeability stainless steel. Based on the experience gained at CERN for CLIC X-band high power loads, the RF design of the load was optimized to ensure high losses for a quite large range of magnetic steels. Test pieces were realized in three different magnetic steels to choose the best suited material commercially available. This paper reports about the RF design, material study, production and impressive high power results of this C-band load.  
 
MOPP119 Measurements and High Power Test of the First C-band Accelerating Structure for SwissFEL 333
 
  • R. Zennaro, J. Alex, A. Citterio, J.-Y. Raguin
    PSI, Villigen PSI, Switzerland
  
  The SwissFEL project is based on a 5.8 GeV C-band Linac which is composed of 104 accelerating structures with a length of 2 m each. Due to the absence of dimple tuning no local frequency correction is possible and hence ultra-precise machining is required. The paper reports on both low level and high power RF test of the first nominal structure produced. The required mechanical precision has been reached and the structure has been successfully power tested to a gradient larger than 50 MV/m, well above the nominal level of 28 MV/m. The measured dark current and break down rates are well in the specifications.  
 
MOPP120 Beam Dynamic Design of a 100 mA, 162.5 Mhz High-Current Linac 336
SUPG033   use link to see paper's listing under its alternate paper code  
 
  • F.J. Jia, J.E. Chen, Y.R. Lu, Z. Wang, W.L. Xia, X.Q. Yan, K. Zhu
    PKU, Beijing, People's Republic of China
  • W.P. Dou, Y. He
    IMP, Lanzhou, People's Republic of China
  
  Funding: This work is supported by the 973 program (No. 2014CB845503) and the NSFC (Grants No. 11079001).
The beam dynamic design of a 100 mA, 162.5 MHz Radio Frequency Quadrupole (RFQ) is presented in this paper. The RFQ will accelerate protons from 85 keV to 3 MeV under the operation mode of continuous-wave (CW). The code PARMTEQM is used to carry out the beam dynamics design and the transmission efficiency has been optimized and improved to more than 99%. In the design of this high-current linac, the space charge effect is analyzed as it can cause emittance growth, nonuniform particle density distribution and resonance effect. The electrode structure parameters generated by PARMTEQM also be adopted by the code of Toutatis to verify the result’s veracity. 		 
 
MOPP122 Construction of the New Amplifiers for the RIKEN-LINAC 339
 
  • K. Suda, E. Ikezawa, O. Kamigaito, N. Sakamoto, K. Yamada
    RIKEN Nishina Center, Wako, Japan
  • Y. Touchi
    SHI, Tokyo, Japan
  
  New tetrode based amplifiers have been constructed for the RIKEN heavy-ion linac, so called RILAC[1], replacing 36-year-old amplifiers to improve their reliability as a main injector for the RIBF accelerator complex. The RILAC is a DC machine and their frequency are tunable between 18 to 40 MHz so as to be capable of accelerating heavy ions with mass-to-charge (m/q) ratios up to 28. The new rf amplifier is based on a tetrode THALES/SIEMENS RS2042SK coupled with a tetrode THALES/SIEMENS RS2012CJ with a grounded grid circuit. The maximum output power is 100 kW with a frequency ranging from 18 to 40 MHz. The amplifier was originally designed for RIKEN Ring Cyclotron. Since we have many experiences with this type of amplifier, some modification to avoid exciting the parasitic modes which might damage the cavity and/or the amplifier itself. Their construction started in April 2013 and installation was performed in January 2014. After the installation their commissioning has been successfully made. For a beam service started in this March the new amplifiers were operated without any troubles. [1]M. Odera et al., Nucl. Instrum. and Methods, 227, 187(1984).  
poster icon Poster MOPP122 [16.391 MB]  
 
MOPP123 Development Activities of Accelerator Instruments for SACLA 342
 
  • Y. Otake, T. Asaka, T. Inagaki, C. Kondo, H. Maesaka, T. Ohshima, T. Sakurai, K. Togawa
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • H. Ego, S. Matsubara
    JASRI/SPring-8, Hyogo-ken, Japan
  
  The X-ray free-electron laser, SACLA, is constantly operated for user experiments aimed at new science. Experimental users demand further experimental abilities, such as many experimental chances by using multi-X-ray beam lines, much better repeatability of the experiment conditions and further intense high-energy X-rays. To equip SACLA with these abilities in the future, we have developed a 2pi /3 CG acceleration structure with an acceleration gradient of over 45 MV/m to adapt operation for generating the intense high-energy X-rays. A high-voltage power supply to charge the PFN of a modulator, a klystron and an acceleration structure were developed to adapt operation for 120 pps operation from the present 30 pps, since 120 pps is more suitable for beam distribution to the multi-beam lines. To meet the experimental repeatability realized by stable timing in a pump-probe experiment, an optical-fiber length control system to mitigate timing drift below 1 fs for 10 minutes was developed. Highly precise cavity temperature control system in an injector for below ±2mK was also realized. Performances of our developed instruments were experimentally tested to be sufficient for our demands.  
 
MOPP124 Development of a 3 MeV Prototype RFQ Structure for High Intensity Proton Linac for ISNS 345
 
  • S.C. Joshi, A. Chaturvedi, S.K. Chauhan, K.K. Das, G.V. Kane, S.V. Kokil, B. Oraon, S. Raghvendra, N.K. Sharma
    RRCAT, Indore (M.P.), India
  
  Raja Ramanna Centre for Advanced Technology (RRCAT) has taken up a program on R&D activities of a 1 GeV, high intensity superconducting proton linac for a spallation neutron source. A 3 MeV Radio Frequency Quadrupole (RFQ) will be used as front end of the pulsed proton linac. A full scale prototype RFQ structure has been designed and fabricated to validate the physics design and manufacturing procedures. The total of 3.46 meter has been divided in three segments for ease in machining. The fabricated RFQ structure has been assembled for low power RF characterization. The RFQ frequency and field tuning exercise is being carried out using 48 stub tuners. The paper will also present the engineering design aspects and fabrication issues for the full scale RFQ structure.  
 
MOPP125 Comparison of Normal Conducting High Energy Accelerating Structures for a Moderate Operating Frequency 348
 
  • V.V. Paramonov
    RAS/INR, Moscow, Russia
  
  The progress in the CERN Linac 4 project confirms the very attractive possibility for single frequency high intensity high energy normal conducting hadron linac. The important part of such linac is the accelerating structure for high energy part. Parameters of possible accelerating structures, referring to PIMS, at operating frequency 352 MHz are considered for proton energy up to 600 MeV. The set of parameters, such as dimensions, RF efficiency, field stability, cooling capability, vacuum conductivity, are considered and compared.  
 
MOPP126 Untrapped HOM Radiation Absorption in the LCLS-II Cryomodules 351
 
  • K.L.F. Bane, C. Adolphsen, C.D. Nantista, T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  • A. Saini, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by Department of Energy contract DE–AC02–76SF00515.
The superconducting cavities in the continuous wave (CW) linacs of LCLS-II are designed to operate at 2 K, where cooling costs are very expensive. One source of heat is presented by the higher order mode (HOM) power deposited by the beam. Due to the very short bunch length-especially in L3 the final linac-the LCLS-II beam spectrum extends into the terahertz range. Ceramic absorbers, at 70 K and located between cryomodules, are meant to absorb much of this power. In this report we perform two kinds of calculations to estimate the effectiveness of the absorbers and the amount of beam power that needs to be removed at 2 K. 		 
 
MOPP127 Wakefield Effects of the Bypass Line in LCLS-II 355
 
  • K.L.F. Bane, T.O. Raubenheimer
    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. 		 
 
MOPP128 Bridging the Gap Between Conventional RF Acceleration and Laser Driven Acceleration 358
MOPOL04   use link to see paper's listing under its alternate paper code  
 
  • M.V. Fazio, V.A. Dolgashev, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  
  For decades conventional RF accelerators have been built and operated with ever increasing capability through a few tens of gigahertz in frequency. More recent research takes advantage of the continuing development of high peak power short pulse lasers to drive accelerator structures at optical frequencies. This jump from RF to optical frequencies skips four orders of magnitude in wavelength. With recent experiments that demonstrate high gradients in metallic structures at millimeter wavelengths one is compelled to consider the viability of new approaches for acceleration in the millimeter-wave to terahertz regime. This paper will explore some of these possibilities.  
 
MOPP129 Status of the FETS Project 361
 
  • A.P. Letchford, M.A. Clarke-Gayther, D.C. Faircloth, S.R. Lawrie
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • S.M.H. Alsari, M. Aslaninejad, J.K. Pozimski, P. Savage
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • J.J. Back
    University of Warwick, Coventry, United Kingdom
  • G.E. Boorman, A. Bosco, S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  • R.T.P. D'Arcy, S. Jolly
    UCL, London, United Kingdom
  • M. Dudman, J.K. Pozimski
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • D.C. Plostinar
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  
  The Front End Test Stand (FETS) under construction at RAL is a demonstrator for front end systems of a future high power proton linac. Possible applications include a linac upgrade for the ISIS spallation neutron source, new future neutron sources, accelerator driven sub-critical systems, high energy physics proton drivers etc. Designed to deliver a 60mA H-minus beam at 3MeV with a 10% duty factor, FETS consists of a high brightness ion source, magnetic low energy beam transport (LEBT), 4-vane 324MHz radio frequency quadrupole, medium energy beam transport (MEBT) containing a high speed beam chopper and non-destructive laser diagnostics. This paper describes the current status of the project and future plans.  
 
MOPP130 A Linac-Based Approach to Modelling an Orbit Separated Cyclotron 364
 
  • D.C. Plostinar, G.H. Rees
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  
  An orbit separated cyclotron (OSC) is a new type of accelerator intended as a proton driver for Accelerator Driven Subcritical Reactors (ADSRs). A ring has been designed based on the new concept that accelerates a proton beam from 500 MeV to 1 GeV in four turns using multi-cell superconducting cavities in each period. From a beam dynamics point of view, the ring can be considered as a “wrapped-up” linac at four times the ring circumference. In this paper we present beam dynamics modelling details when using 3D linac codes and cavity field maps. We conclude that the versatility of codes such as TraceWin, allows detailed machine modelling and improved design procedures that take into account various aspects including orbit distortion caused by transverse deflecting fields in the cavities.  
 
MOPP132 Development of a Micro-Pulse Electron Gun Based Upon pi-Mode Dual-Cavity 367
 
  • L. Liao, Q. Gu, M. Zhang, M.H. Zhao
    SINAP, Shanghai, People's Republic of China
  
  The concept of a novel micro-pulse electron gun (MPG) based upon pi-mode dual-cavity is proposed and analyzed in this paper, and we termed it as dual-cavity micro-pulse electron gun (D-MPG) as compared to single-cavity standard MPG. From simulations, it is clear that the D-MPG is capable of yielding dozens of ampere peak currents and a few ps bunch length. Thought the mechanism for dual cavity is not fully understand, the D-MPG has demonstrate the potential to be the injectors for FEL and THz radiation facilities. Also it is a good candidate to replace the thermal cathode for industrial and medical accelerator system because of the cost-effective of the D-MPG.  
 
MOPP133 Measurements of Cavity Misalignment by Beam Induced HOM Excited in 9-cell Superconducting Cavities 370
 
  • A. Kuramoto
    Sokendai, Ibaraki, Japan
  • N. Baboi
    DESY, Hamburg, Germany
  • H. Hayano
    KEK, Ibaraki, Japan
  
  Detection of cavity misalignment in the ILC superconducting cavities inside of the cryomodules can be done by using beam induced Higher Order Modes (HOM). It is beneficial to identify possible source of emittance growth by cavity misalignment. Beam pipe modes which are localized in both ends of the cavity and TE111 1/9 pi mode which is localized in the center of the cavity are focused in this research. Deviations of these electrical centers from beam trajectory reference indicate cavity misalignment and bending. We measured beam-induced HOM in STF cavities of the STF accelerator at KEK in 2012 – 2013 and TESLA cavities of FLASH at DESY in 2013. We could identify beam pipe modes and TE111 1/9 pi mode in STF cavities and TESLA cavities at around 2.1 GHz and 1.6 GHz, both of which were very small signals. The electrical center of these beam pipe mode are studied by stretched wire method, beads perturbation method and simulations by CST MICROWAVE STUDIO 2012 and HFSS 12. In this paper, the results of these measurements and simulations are summarized.  
 
MOPP134 Superconducting Accelerating Cavity Pressure Sensitivity Analysis and Stiffening 373
 
  • J. Rodnizki, Y. Ben Aliz, A. Grin, Z. Horvitz, A. Perry, L. Weissman
    Soreq NRC, Yavne, Israel
  • G.K. Davis
    JLab, Newport News, Virginia, USA
  • J.R. Delayen
    ODU, Norfolk, Virginia, USA
  
  The SARAF Prototype Superconducting Module (PSM) houses six 176 MHz Half Wave Resonators(HWR). The PSM accelerates protons and deuterons from 1.5 MeV/u to 4 and 5.6 MeV. The HWRs are highly sensitive to the coolant liquid Helium pressure fluctuations which limit the available beam power to 2kW per cavity out of 4kW RF amplifier and coupler and so might limit the available beam current to 2mA depending on the output energy. The flat shape of the cavity along the beam line in the area of the high electric field generates the high sensitivity of the Eigen mode frequency to helium pressure. The evaluated cavity sensitivity is full consistent with the measured values. It was explored that the tuning system (the fog structure) has a significant contribution to the cavity sensitivity. By using ribs or by modifying the rigidity of the fog we may reduce the HWR sensitivity by a factor of 3. This analysis is applied to study the stresses on the cavity during cool down and warm up to avoid plastic deformation as the Niobium yield is an order of magnitude lower in room temperature.  
 
MOPP135 Exact Solutions of the Vlasov Equation in Magnetic Field 377
 
  • O.I. Drivotin, D.A. Ovsyannikov
    St. Petersburg State University, St. Petersburg, Russia
  
  Funding: This work was supported by St.-Petersburg State University grant #9.38.673.2013.
This report is devoted to self-consistent distributions for charged particle beam which are regarded as solutions of the Vlasov equation. New approach based on covariant formulation of the Vlasov equation* is developed. Such approach allows using various coordinates in the phase space. It is shown how to apply this approach to the problem of finding of solutions of the Vlasov equation for charged particle beam. Solutions obtained within the framework of this approach are presented. Most known example is the Kapchinsky-Vladimirsky distribution. Wide classes of distributions for uniformly charged beam are also considered.
* O.I. Drivotin. Covariant formulation of the Vlasov equation. Proc. of 2011 Int. Part. Acc. Conf.(IPAC'2011), San-Sebastian, Spain, 2011. accelconf.web.cern.ch/accelconf/ipac2011/papers/wepc114.pdf 		 
 
MOPP137 Design Progress of the MYRRHA Low Energy Beam Line 381
 
  • R. Salemme, L. Medeiros Romão, D. Vandeplassche
    Studiecentrum voor Kernenergie - Centre d'Étude de l'énergie Nucléaire (SCK•CEN), Mol, Belgium
  • M.A. Baylac, D. Bondoux, F. Bouly, J.-M. De Conto, E. Froidefond
    LPSC, Grenoble Cedex, France
  • J.-L. Biarrotte
    IPN, Orsay, France
  • D. Uriot
    CEA/DSM/IRFU, France
  
  The MYRRHA project, a flexible spectrum neutron irradiation facility, is designed according to the Accelerator Driven System (ADS) reactor concept. The MYRRHA driver consists of a high power superconducting proton LINAC. A prototype of the front end injector is being built up into a test platform conceived to experimentally address its design issues. Currently, the ECR proton source has been industrially procured. LPSC Grenoble designed the subsequent Low Energy Beam Transport (LEBT) section. Right before the RFQ, a short section hosts an electrostatic beam chopper producing carefully controlled beam interruptions. In this paper the status of the LEBT design with the associated beam instrumentation is reviewed. Future experimental plans including LEBT beam characterization and optimization of the beam transmission are presented.  
 
MOPP138 Fabrication and Measurements of 500 MHz Double Spoke Cavity 385
SUPG025   use link to see paper's listing under its alternate paper code  
 
  • H. Park, J.R. Delayen
    JLab, Newport News, Virginia, USA
  • J.R. Delayen, C.S. Hopper, H. Park
    ODU, Norfolk, Virginia, USA
  
  The 500 MHz double spoke cavity has been designed for a high velocity application such as a compact electron accelerator at Center for Accelerator Science at Old Dominion University and is being built at Jefferson Lab. The geometry specific to the double spoke cavity requires a variety of tooling and fixtures. Also a number of joints are expected to make it difficult to maintain the geometric deviation from the design minimal. This paper will report the fabrication technique, resulting tolerance from the design, and comparison between the measurements and simulations.  
poster icon Poster MOPP138 [2.144 MB]  
 
MOPP139 Studies of Coherent Synchrotron Radiation in the Jefferson Lab FEL Driver with Implications for Bunch Compression 388
MOPOL12   use link to see paper's listing under its alternate paper code  
 
  • C. Tennant, D. Douglas, R. Li
    JLab, Newport News, Virginia, USA
  • C.-Y. Tsai
    Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
  
  Funding: Work supported by the Office of Naval Research and the High Energy Laser Joint Technology. Jefferson Laboratory work is supported under U.S. DOE Contract No. DE-AC05-06OR23177.
The Jefferson Laboratory IR FEL Driver provides an ideal test bed for studying a variety of beam dynamical effects. Recent studies focused on characterizing the impact of coherent synchrotron radiation (CSR) with the goal of benchmarking measurements with simulation. Following measurements to characterize the beam, we quantitatively characterized energy extraction via CSR by measuring beam position at a dispersed location as a function of bunch compression. In addition to operating with the beam on the rising part of the linac RF waveform, measurements were also made while accelerating on the falling part. For each, the full compression point was moved along the backleg of the machine and the response of the beam (distribution, extracted energy) measured. Initial results of start-to-end simulations using a 1D CSR algorithm show remarkably good agreement with measurements. A subsequent experiment established lasing with the beam accelerated on the falling side of the RF waveform in conjunction with positive momentum compaction (R56) to compress the bunch. The success of this experiment motivated the design of a modified CEBAF-style arc with control of CSR and microbunching effects. 		 
 
MOPP140 Simulations for the High Gradient, Low Emittance Supergun RF Photoinjector 391
SUPG036   use link to see paper's listing under its alternate paper code  
 
  • A.D. Cahill, A. Fukasawa, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • L. Faillace
    RadiaBeam, Marina del Rey, California, USA
  • B. Spataro
    INFN/LNF, Frascati (Roma), Italy
  • A. Valloni
    CERN, Geneva, Switzerland
  
  A new S-Band photoinjector is being developed at UCLA that will feature a large accelerating gradient at 160 MeV/m creating a beam with approximately 6.5 MeV at the exit. Because of the large accelerating gradient and other considerations, such as cooling and manufacturing, the new Supergun will be coupled into using a coaxial method, rather than side coupling. With the large accelerating gradient we hope to create very low emittance beams on the order of 0.025 mm mrad. These beams can then be used for a number of purposes, mainly for high quality beams used in FELs. Electric simulations have been done using HFSS and Superfish. Heating and mechanical simulations were done using Ansys. Finally, beam simulations were completed with GPT.