THPP —  Poster Session   (04-Sep-14   16:00—18:00)
Chair: S. Ramberger, CERN, Geneva, Switzerland
Paper Title Page
THPP003 Cooling of High Pressure Insulating Gas for 3 MeV DC Accelerator: an Alternate Approach 839
 
  • S.R. Ghodke, S. Acharya, R. Barnwal, K.P. Dixit, L.M. Gantayet, B.S. Israel, D. Jayaprakash, K. Mahender, K.C. Mittal, S. Nayak, R.N. Rajan, D.K. Sharma, V. Sharma, S.K. Suneet, D.P. Suryaprakash
    BARC, Mumbai, India
  
  3 MeV Accelerator Project working inside the ‘Electron Beam Centre’ (EBC) building at Kharghar, Navi Mumbai. Generally in DC and Pelletron accelerators Nitrogen/SF6 gas is taken out from accelerator tank and it is cooled by separate heat exchanger and blower unit outside the accelerator tank. In our alternate approach we have designed fan/ blower to work under high pressure inside accelerator tank. Fans are designed to work in high pressure SF6 environment at 7 bar absolute pressure with 42 kg/m3 SF6 gas density. Fan throughs air over radiator type finned tube heat exchanger, installed inside accelerator tank. Fan speeds are controlled through variable frequency drive. Two numbers of such assemblies are fabricated, installed and tested in Nitrogen and SF6 gas environment at different pressure and variable fan speed. Performances are recorded and plotted in graphical form. These cooling systems are shown excellent performance in last five years. Paper will discuss about design of cooling system, cooling calculation of fan, fabrication of fan and heat exchanger, 5 TR chiller unit, variable frequency drive, fan performance etc.  
poster icon Poster THPP003 [1.644 MB]  
 
THPP004 Design, Development and Initial Results of Solid State Magnetron Modulator 843
 
  • A.R. Tillu, S. Chandan, K.P. Dixit, K.C. Mittal, H.E. Sarukte
    BARC, Mumbai, India
  
  A prototype solid state pulse modulator based on Induction Adder Topology has been designed ans is currently being tested on a S Band Pulsed magnetron rated for 3.2M W Peak RF Power. After successful lab tests the modulator is intended for use in cargo scanning and radiography applications. Currently the topology consists of 4 no.s of single turn primaries driven independently at voltages not more than 1000V. The secondary encircles all the four primaries to generate the desired pulsed voltage across the magnetron. The designed output pulse parameters are 50k V, 120A, 4micro s, at a pulse repetition rate of 250 pps. The paper describes the design and development of the Epoxy Cast Pulse transformer and the Low Inductance Primary Circuit. The rise time measured was < 400ns, and the reverse voltage at the end of the pulse was less than 12kV (at 43k V pulse). The testing was done at low PRF, on two different magnetrons having different operating points to demonstrate fairly good impedance independent operating characteristic of the magnetron modulator. Initial test results on the Resistive load and Magnetron load will also be discussed  
poster icon Poster THPP004 [1.575 MB]  
 
THPP005 A New High Current and Single Bunch Injector at ELSA 847
 
  • M. Schedler, P. Hänisch, W. Hillert, D. Proft
    ELSA, Bonn, Germany
  • J. Zappai
    Uni Bonn, Bonn, Germany
  
  At the Electron Stretcher Facility ELSA of Bonn University, an increase of the maximum stored beam current from 20 mA to 200 mA is planned for the stretcher ring. In order to keep the desired duty cycle of the post acceleration mode at about 80 \% a new high current injector operating at 3 GHz has been built. It provides an electron beam with an energy of 20 MeV and a beam current of 800 mA in pulsed operation. A prebuncher, travelling wave buncher system and an energy compressing system are installed in order to enhance the beam acceptance of the linac and to reduce the energy spread in order to achieve an improved injection efficiency into the booster synchrotron. For studying accelerators impedances and beam instabilities the linac is able to produce single bunches with a pulse current of 2 A which will be accumulated in the stretcher ring.  
 
THPP007 Uniform Current Density for BLIP Target at Brookhaven 200 MeV Linac 850
 
  • D. Raparia, B. Briscoe, P. Cerniglia, R. Connolly, C. Cullen, D.M. Gassner, R.L. Hulsart, R.F. Lambiase, V. Lo Destro, L.F. Mausner, R.J. Michnoff, P. Thieberger, M. Wilinski
    BNL, Upton, Long Island, New York, USA
  
  Bulk of the beam from the linac is used for Brookhaven linac isotope producer (BLIP). The average current from the linac is up 125 uA. At this current BLIP has several target failures and yield uncertainty due to partially melted target salt. To reduce current density, we have tried octupoles in the past but did not produce uniform beam as calculated due to the x-y coupling present in the linac. A beam painting scheme with help of one x and y steers with 90 phase leg at 5 kHz will provide desire current density at the target. This paper discuss beam optics of the blip transport line and beam footprint on the target with given constrains.  
 
THPP009
 BEPCII Linac Accelerator Collider Status and Improvement  
 
  • G.H. Chen
    IHEP, Beijing, People's Republic of China
  
  BEPCII is an upgrade project of Beijing Electron Positron Collider . Linac is not only requires injector to have a higher beam energy (2.3GeV) for high energy physics injection and Synchrotron radiation (2.5GeV), but also a higher beam current . The Linac operation is stable and reliable, strong protection the beam tuning BEPCII engineering standards. In order to meet the higher energy region physics research, in recent years, BEPCII Linac accelerator energy has been increased to 2.62GeV. During the injection, we need to focus on the longitudinal time relation about storage ring accelerator and linear colliders, to improve the injection rate.  
 
THPP010
 An Implementation of new electronic tube power source for the CSNS 3MeV RFQ  
 
  • S.H. Liu, J. Li
    IHEP, Beijing, People's Republic of China
  
  Electronic tube is a great invention since the beginning of last century, which strongly promoted the development of the electronics industry. After more than forty years of research, the technology of electronic tube is fully matured, which is usually used at 300MHz or less. The Power source of CSNS 3 MeV RFQ works on 324MHz and 700kW. On account of the low cost,small volume and large load capacity, refusing the usual tool -Klystron,we first applied the 4616 tetrode to design RFQ power source for CSNS. We tried a variety of methods to find the best working condition in the process of commissioning. For example, we properly increased the inductors and capacitors of PSM power supply output high voltage line to suppress over shoot and improve the stability of positive pressure. We also add nitrogen to the output cavity to increase the pressure resistance of anode current. Finally, for the first time, Each of tetrode power source could keep running stably at 324MHz and 350kW for more than 48h. This also provides a new idea for the selection of accelerator power source.  
 
THPP011
 A high energy electron radiography system based on electron linac  
 
  • Z.M. Zhang, S. Cao, Q.T. Zhao, Y.T. Zhao
    IMP, Lanzhou, People's Republic of China
  • Y.-C. Du, W.-H. Huang
    TUB, Beijing, People's Republic of China
  • W. Gai
    ANL, Argonne, Illinois, USA
  
  Abstract: High energy electron radiography technique, a new scheme to diagnose the high energy density matter, was proposed in 2012 by Institute of Modern Physics (IMP). The high energy density physics experimental research needs a fast, temporal and 3-dimensional diagnostic system to monitor the density evolution during ~200ns compression time. A prove-of-principle experiment was carried out on the 50MeV electron linac accelerator of Tsinghua University. 1.5um spatial resolution was measured by imaging a TEM grid with magnetic lens imaging system. Meanwhile, the simulation research on the interaction between the high energy electron and dense matter was also implemented to verify that the 1~2GeV electrons could penetrate the 200ug/cm2 dense matter with relative revolution in both spatial and time dimensions through an appropriate magnetic imaging system.  
 
THPP012 A Prototype 1 Mev X-Band Linac for Aviation Cargo Inspection 853
 
  • M. Jenkins, P.K. Ambattu, G. Burt
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • S. Andrews, T.A. Cross, C.R. Weatherup
    e2v, Chelmsford, Essex, United Kingdom
  • P.A. Corlett, P. Goudket, A.R. Goulden, P.A. McIntosh, K.J. Middleman, Y.M. Saveliev, R.J. Smith, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • S.A. Griffiths, M.D. Hancock, T. Hartnett, C. Hill, J.P. Hindley, B.G. Martlew, N. Templeton
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  
  Aviation cargo Unit Load Device (ULD) containers are typically much smaller than standard shipping containers, with a volume of around 1m3. Standard 3-6 MeV X-ray screening linacs have too much energy to obtain sufficient contrast when inspecting ULD’s, hence a lower 1 MeV linac is required. In order to obtain a small physical footprint, which can be adapted to mobile platform applications a compact design is required, hence X-band technology is the ideal solution. A prototype 1 MeV linac cavity has been designed by Lancaster University, manufactured by Comeb (Italy) and tested at STFC Daresbury Laboratory using an e2v magnetron, modulator and electron gun. The cavity is a bi-periodic π/2 structure, with beam-pipe aperture coupling to simplify the manufacture at the expense of shunt impedance. The design, manufacture and testing of this linac structure is presented.  
 
THPP013 Prototype Development of the CLIC Crab Cavities 856
 
  • G. Burt, P.K. Ambattu, A.C. Dexter, M. Jenkins, C. Lingwood, B.J. Woolley
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • V.A. Dolgashev
    SLAC, Menlo Park, California, USA
  • P. Goudket, P.A. McIntosh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • A. Grudiev, G. Riddone, A. Solodko, I. Syratchev, R. Wegner, W. Wuensch
    CERN, Geneva, Switzerland
  • C. Hill, N. Templeton
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  
  CLIC will require two crab cavities to align the beams to provide an effective head-on collision with a 20 mdeg crossing angle at the interaction point. An X-band system has been chosen for the crab cavities. Three prototype cavities have been developed in order to test the high power characteristics of these cavities. One cavity has been made by UK industry and one has been made using the same process as the CLIC main linac in order to gain understanding of breakdown behaviour in X-band deflecting cavities. The final cavity incorporates mode-damping waveguides on each cell which will eventually contain SiC dampers. This paper details the design, manufacture and preparation of these cavities for testing and a report on their status.  
 
THPP014 Catalogue of Losses for the Linear IFMIF Prototype Accelerator 860
THPOL09   use link to see paper's listing under its alternate paper code  
 
  • N. Chauvin, P.A.P. Nghiem, D. Uriot
    CEA/IRFU, Gif-sur-Yvette, France
  • M. Comunian
    INFN/LNL, Legnaro (PD), Italy
  • C. Oliver
    CIEMAT, Madrid, Spain
  
  One of the activities of the EVEDA (Engineering Validation and Engineering Design Activities) phase of the IFMIF (International Fusion Materials Irradiation Facility) project consists in building, testing and operating, in Japan, a 125 mA/9 MeV deuteron accelerator, called LIPAc, which has been developed in Europe. For the accelerator safety aspects, a precise knowledge of beam loss location and power deposition is crucial, especially for a high intensity, high power accelerator like LIPAc. This paper presents the beam dynamics simulations allowing to estimate beam losses in different situations of the accelerator lifetime: starting from scratch, beam commissioning, tuning or exploration, routine operation, sudden failure. Some results of these studies are given and commented. Recommendations for hot point protection, beam stop velocity, beam power limitation are given accordingly.  
slides icon Slides THPP014 [4.780 MB]  
 
THPP015 Status of the FAIR Proton Source and LEBT 863
 
  • N. Chauvin, O. Delferrière, Y. Gauthier, P. Girardot, J.L. Jannin, A. Lotode, N. Misiara, J. Neyret, F. Senée, C.S. Simon, O. Tuske
    CEA/IRFU, Gif-sur-Yvette, France
  • R. Berezov, J. Fils, P. Forck, R. Hollinger, V. Ivanova, C. Ullmann, W. Vinzenz
    GSI, Darmstadt, Germany
  • A. Maugueret
    CEA/DSM/IRFU, France
  
  The unique Facility for Antiproton and Ion Research – FAIR will deliver stable and rare isotope beams covering a huge range of intensities and beam energies. A significant part of the experimental program at FAIR is dedicated to antiproton physics that requires an ultimate number 7x1010 cooled pbar/h. The high-intensity proton beam that is necessary for antiproton production will be deliver by a dedicated 75 mA/70 MeV proton linac. The injector section of this accelerator is composed by an ECR source, delivering a pulsed 100 mA H+ beam (4 Hz) at 95 keV and a low energy beam transport (LEBT) line required to match the beam for the RFQ injection. The proposed design for the LEBT is based on a dual solenoids focusing scheme. A dedicated chamber containing several diagnostics (Alisson scanner, Wien filter, SEM grid, Iris, Faraday Cup) will be located between the two solenoids. At the end of the beam line, an electrostatic chopper system is foreseen to inject up to 50μseconds long beam pulses into the RFQ. The status of LEBT simulations, design and fabrication of the FAIR proton injector will be presented.  
 
THPP016 Nitrogen-Treated Cavity Testing at Cornell 866
 
  • D. Gonnella, F. Furuta, G.M. Ge, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: U.S. Department of Energy
Recent results from Cornell, FNAL, and TJNAF have shown that superconducting RF cavities given a heat treatment in a nitrogen atmosphere show higher Q0 at operating gradients at 2.0 K than standard SRF cavities. Here we present on recent results at Cornell in which five single cell cavities and three 9-cell cavities were tested after receiving various nitrogen-doping treatments. Cavity performance was correlated with treatment, and samples treated with the cavities were analyzed with SIMS. These results provide new insights into the science behind the excellent performance that is observed in these cavities. 		 
 
THPP017 Beam-Based HOM Studies of the Cornell Energy Recovery Linac 7-Cell SRF Cavity 869
 
  • D.L. Hall, A.C. Bartnik, M.G. Billing, R.G. Eichhorn, G.H. Hoffstaetter, M. Liepe, C.E. Mayes, P. Quigley, V. Veshcherevich
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: NSF Grant DMR-0807731
The 1.3 GHz 7-cell SRF cavity for the Cornell ERL main linac is optimized for high beam current ERL operation with injected CW beam currents of 100 mA. Beam stability at 100 mA requires very strong damping of the Higher-Order-Modes (HOM) in the cavity by HOM beamline absorbers at the ends of the cavity. To verify the optimized design of the cavity and the HOM damping scheme, a prototype 7-cell main linac cavity was installed into the Cornell Horizontal Test Cryomodule (HTC), and inserted into the beamline of the Cornell ERL high current photo-injector. A beam-based method was then used to search for the presence of dangerous HOMs. Individual HOMs were excited using a charge-modulated beam, after which their effect upon an unmodulated beam was observed using a BPM. Data collected was used to calculate loaded Q of observed HOMs. Results show that it is very unlikely that HOMs will cause BBU in the Cornell ERL. In addition, measurements of the temperature rise of the HOM absorber rings during high current CW beam tests were consistent with simulations, indicating that the optimized main linac cavity is capable of operating at the specified current of 100mA in an ERL configuration. 		 
 
THPP018 Sample Plate Studies Using a High Field TE Cavity With Thermometry Mapping System 873
 
  • D.L. Hall, C.D. Burton, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: NSF Career Grant PHY-0841213
A TE-Mode sample plate cavity capable of sustaining peak fields of >90 mT on the surface of a 10cm diameter sample plate has been developed and tested at Cornell. A thermometry mapping system composed of 40 Allen-Bradley resistors, mounted on the outside of the sample plate, is capable of measuring the surface resistance of the sample with a resolution of 1 nOhm and a spatial resolution of 0.5 cm. In this paper we present the design and expected performance of this high field TE cavity, and show data taken with a sample plate of niobium as well as results from tests qualifying the performance of the thermometry mapping system. 		 
 
THPP019 Low Kick Coupler for Superconducting Cavities 876
 
  • R.G. Eichhorn, C. Egerer, V. Veshcherevich
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Results from the high current, low emittance photo injector at Cornell revealed that even with two opposing input couplers, the beam emittance is affected by the coupler kick. As a result, a coupler with low transverse kick is proposed for use in superconducting accelerating cavities. In this coupler, a rectangular waveguide transforms into a coaxial line inside the beam pipe. The geometry of the coupler is tuned to minimize the transverse kick that is important for linear accelerators with low emittance. The coupler can be used in ERL injectors or other linacs for high brightness light sources.  
 
THPP021 Analysis of the RF Test Results from the On-going Accelerator Cavity Production for the European XFEL 879
 
  • D. Reschke, S. Aderhold, V. Gubarev, J. Schaffran, N.J. Walker
    DESY, Hamburg, Germany
  • L. Monaco
    INFN/LASA, Segrate (MI), Italy
  • Y. Yamamoto
    KEK, Ibaraki, Japan
  
  Funding: The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no 283745 (CRISP)
The main Linac of the European XFEL will consist of 100 superconducting accelerator modules, operated at an average design gradient of 23.6 MV/m. The fabrication by industry (which includes chemical surface preparation) of the required 800 superconducting cavities is now in full swing, with approximately 400 cavities having been delivered to date. In this interim report, we present an analysis of the RF acceptance tests amassed so far. 		 
 
THPP022 Efficiency of High Order Modes Extraction in the European XFEL Linac 883
THPOL05   use link to see paper's listing under its alternate paper code  
 
  • A.A. Sulimov, J. Iversen, D. Kostin, W.-D. Möller, D. Reschke, J.K. Sekutowicz, J.H. Thie
    DESY, Hamburg, Germany
  • D. Karolczyk, K. Kasprzak, S. Myalski, M. Wiencek, A. Zwozniak
    IFJ-PAN, Kraków, Poland
  
  The serial production of components for the European XFEL linac was started in 2011 and reached the planned level of 8 cavities (1 module) per week in 2013. The measurements of High Order Modes (HOM) characteristics under cryogenic conditions (2K) are being done at the Accelerating Module Test Facility (AMTF) by the IFJ-PAN Team in collaboration with DESY groups. More than 50 % of the cavities have been already produced and 30 % of the whole amount were measured during either cavity vertical tests or module tests. We present first statistics of these measurements and analyze the efficiency of HOM extraction.  
poster icon Poster THPP022 [0.801 MB]  
 
THPP023 Affordable Short Pulse Marx Modulator 886
 
  • R.A. Phillips, G. DelPriore, M.P.J. Gaudreau, M.K. Kempkes
    Diversified Technologies, Inc., Bedford, Massachusetts, USA
  • J.A. Casey
    Rockfield Research Inc., Las Vegas, Nevada, USA
  
  High energy, short-pulse modulators are being re-examined for the Compact Linear Collider (CLIC) and numerous X-Band accelerator designs. At the very high voltages required for these systems, all of the existing designs are based on pulse transformers, which significantly limit their performance and efficiency. There is not a fully optimized, transformer-less modulator design capable of meeting the demanding requirements of very high voltage pulses at short pulse widths. Under a U.S. Department of Energy grant, Diversified Technologies, Inc. (DTI) is developing a short pulse, solid-state Marx modulator. The modulator is designed for high efficiency in the 100 kV to 500 kV range, for currents up to 250 A, pulse lengths of 0.2 to 5.0 μs, and risetimes <300 ns. Key objectives of the development effort are modularity and scalability, combined with low cost and ease of manufacture. For short-pulse modulators, this Marx topology provides a means to achieve fast risetimes and flattop control that are not available with hard switch or transformer-coupled topologies. The system is in the final stages of testing prior to installation at Yale University.  
 
THPP025 RF Design and Low Power Measurements of a Nose-Cone Single Gap Buncher Cavity 888
 
  • O. González, I. Bustinduy, N. Garmendia, P.J. González, L. Muguira, J.L. Muñoz, A. Zugazaga
    ESS Bilbao, Zamudio, Spain
  
  A nose-cone single-gap buncher cavity for the Medium Energy Beam Transport (MEBT) has been fully designed, manufactured and measured under low-power conditions at ESS-Bilbao. The main steps of the design process are first reviewed. Second, the cavity is thoroughly measured and characterized by means of an automatic test procedure based on the bead-pull technique. Third, the simulated and measured results obtained for the main figures of merit are compared. Specifically, the results for the resonant frequency, the coupling and quality factors, the electric field profile, the R over Q ratio, the transit time factor and the tuning range are carefully analysed.  
 
THPP027 Commissioning of the Linac4 Low Level RF and Future Plans 892
 
  • P. Baudrenghien, J. Galindo, G. Hagmann, J. Noirjean, D. Stellfeld, D. Valuch
    CERN, Geneva, Switzerland
  
  Linac4 is a new 86-m long normal-conducting linear accelerator that will provide 160 MeV H− to the CERN PS Booster (PSB), and replace the present 50 MeV proton Linac2. The Low Level RF (LLRF) system has to control the RFQ, two choppers, three bunching cavities, twenty two accelerating cavities and one debuncher in the transfer line to the PSB. To optimize the transfer into the 1 MHz PSB bucket, the machine includes fast choppers (synchronized with the PSB RF) and a voltage modulation of the last two cavities that will provide Longitudinal Painting for optimum filling. The commissioning in the tunnel with beam has started in October 2013. So far the part consisting of the RFQ, the three bunching cavities, and the first DTL is operational. The rest of the machine will be progressively commissioned till end 2015. The paper presents the LLRF system. First results from the commissioning (with a prototype regulation system) are shown and the more sophisticated algorithms under development are presented.  
 
THPP028 Design and Beamloading-Simulations of a Pre-Bunching Cavity for the CLIC Drive Beam Injector 895
SUPG001   use link to see paper's listing under its alternate paper code  
 
  • M. Dayyani Kelisani, S. Döbert, H. Shaker
    CERN, Geneva, Switzerland
  • H. Shaker
    IPM, Tehran, Iran
  
  The CLIC project is developing a multi-TeV center-of-mass electron-positron collider based on high-gradient, room-temperature accelerating structures and a novel two-beam RF power generation scheme. The RF power for the CLIC accelerating structures is provided by the so-called drive beam which is a low energy, high current electron beam. The drive beam will be generated from a high current (up to 5 A) pulsed (142μs) thermionic electron gun and then followed by a bunching system. The bunching system is composed of three sub-harmonic bunchers operating at a frequency of 499.75 MHz, a pre-buncher and a traveling wave buncher both operating at 999.5MHz. The pre-buncher cavity, which has a great importance on minimization the satellite population, should be designed with special consideration of the high beam loading effect due to the high current beam crossing the cavity. In this work we report on RF design, analytical beam loading calculations and simulations for the CLIC drive beam injector pre-buncher cavity.  
 
THPP029 Electropolishing Simulation on Full Scale Radio Frequency Elliptical Structures 898
 
  • L.M.A. Ferreira
    CERN, Geneva, Switzerland
  • H. Rana, J.A. Shirra
    Loughborough University, Leicestershre, United Kingdom
  
  This paper describes a methodology to simulate the electropolishing of a full scale radio frequency (RF) accelerating elliptical cavity through data acquired by means of a rotating disc electrode (RDE) in a three electrode set-up. The method combines laboratorial data from the RDE with computational simulation performed with Comsol Multiphysics® either for the primary and secondary current distribution as well as to account for the local effect of hydrodynamic perturbations. The results are compared with experimental data from the electropolishing of niobium 704 MHz and five cell cavity from the Superconducting Proton Linear Accelerator (SPL) R&D project at CERN.  
poster icon Poster THPP029 [0.177 MB]  
 
THPP030 Status of the Design Study for 10 MHz Post-accelerated Radioactive Ion Beams at HIE-ISOLDE 901
 
  • M.A. Fraser, R. Calaga
    CERN, Geneva, Switzerland
  
  A ten-fold increase in the bunch spacing of post-accelerated radioactive ion beams has been requested by several research groups at ISOLDE, CERN in order for experiments to use time-of-flight particle identification and background suppression techniques. It is proposed to bunch externally into the existing REX-ISOLDE RFQ at a sub-harmonic frequency of 10.128 MHz to produce the desired 100 ns bunch separation with minimal loss in transmission. The status of a beam dynamics design study carried out to meet this request will be presented in the framework of the HIE-ISOLDE linac upgrade at CERN.  
 
THPP031 Plans for an ERL Test Facility at CERN 905
 
  • E. Jensen, O.S. Brüning, R. Calaga, K.M. Schirm, R. Torres-Sanchez, A. Valloni
    CERN, Geneva, Switzerland
  • K. Aulenbacher
    IKP, Mainz, Germany
  • S.A. Bogacz, A. Hutton
    JLab, Newport News, Virginia, USA
  • M. Klein
    The University of Liverpool, Liverpool, United Kingdom
  
  The baseline electron accelerator for LHeC and one option for FCC-he is an Energy Recovery Linac. To prepare and study the necessary key technologies, CERN has started – in collaboration with JLAB and Mainz University – the conceptual design of an ERL Test Facility (ERL-TF). Staged construction will allow the study under different conditions with up to 3 passes, beam energies of up to about 1 GeV and currents of up to 50 mA. The design and development of superconducting cavity modules, including coupler and HOM damper designs, are also of central importance for other existing and future accelerators and their tests are at the heart of the current ERL-TF goals. The ERL-TF could also provide a unique infrastructure for several applications that go beyond developing and testing the ERL technology at CERN. In addition to experimental studies of beam dynamics, operational and reliability issues in an ERL, it could equally serve for quench tests of superconducting magnets, as physics experimental facility on its own right or as test stand for detector developments. This contribution will describe the goals and the concept of the facility and the status of the R&D.  
 
THPP032 Magnetic Characterization of Fast-Pulsed Quadrupole Magnets for Linac4 909
SUPG006   use link to see paper's listing under its alternate paper code  
 
  • S. Kasaei, M.C.L. Buzio, O. Crettiez, V. Della Selva, L. Fiscarelli, J. Garcia Perez, J.-B. Lallement
    CERN, Geneva, Switzerland
  
  Linac4, currently being built at CERN, includes 24 quadrupole magnets characterized by narrow apertures and fast excitation cycles which make accurate magnetic measurements challenging. This paper describes the method used for the measurement, which is a combination of techniques based on stretched wire, rotating and fixed search coils. We show how these different instruments can be used in a complementary way to derive information on different aspects of the magnetic behaviour, such as the impact of hysteresis and dynamic eddy current effects. We summarize the results of the series measurement campaign, which include field strength, harmonic components, and the offset and orientation of the magnetic axis. Finally, we discuss the relevance of these measurements as their impact to the operation of the linac.  
 
THPP033 Linac4 Transverse and Longitudinal Emittance Reconstruction in the Presence of Space Charge 913
THPOL10   use link to see paper's listing under its alternate paper code  
 
  • J.-B. Lallement, G. Bellodi, V.A. Dimov, A.M. Lombardi, M. Yarmohammadi Satri
    CERN, Geneva, Switzerland
  • M. Yarmohammadi Satri
    IPM, Tehran, Iran
  
  Linac4 is a pulsed, normal-conducting 160 Mev H− linear accelerator presently under construction at CERN. It will replace the present 50 MeV Linac2 as injector of the proton accelerator complex as part of a project to increase the LHC luminosity. The 3 MeV front end, composed of a 45 keV ion source, a Low Energy Beam transport (LEBT), a 352 MHz Radio Frequency Quadrupole (RFQ) at 3 MeV and Medium Energy Beam Transport (MEBT) housing a beam chopper, and the first Drift Tube Linac (DTL) tank at 12 MeV have been commissioned during the first half of 2014. The transverse and longitudinal emittance reconstruction technique in the presence of space charge, that will be used for the next commissioning stages and permanently during the Linac operation, was successfully tested and validated. The reconstruction method and the results obtained at 3 and 12 MeV are presented in this paper.  
 
THPP034 Toolbox for Applying Beam-Based Alignment to Linacs 916
 
  • A. Latina, D. Pellegrini, J. Pfingstner, D. Schulte
    CERN, Geneva, Switzerland
  • E. Adli
    University of Oslo, Oslo, Norway
  
  Tests of Beam-Based Alignment have been performed at FACET, at SLAC in the USA, and at Fermi, at Elettra in Trieste, Italy, with very promising results. Dispersion-Free Steering and Wakefield-free steering have been successfully applied to both machines. In order to make the correction process as automatic as possible, a set of robust tools has been developed, which allowed to span a large set of parameters. These tools and some of the experimental results performed at both machines are presented in this paper.  
 
THPP035 Deceleration Measurements of an Electron Beam in the CLIC Test Facility 3 920
SUPG003   use link to see paper's listing under its alternate paper code  
 
  • R.L. Lillestøl, S. Döbert
    CERN, Geneva, Switzerland
  • E. Adli
    University of Oslo, Oslo, Norway
  
  The Test Beam Line at the CLIC Test Facility 3 at CERN is a proof-of-principle of the future CLIC decelerators, which will extract a large amount of beam energy for acceleration of the main CLIC beams. The current beamline consists of a FODO lattice with 13 Power Extraction and Transfer Structures (PETS). We discuss beam deceleration measurements of up to 37 %, taking into account effects from the bunch length and the bunch phase. The 12 GHz phase is reproduced based on measurements in a PETS with an uncombined beam. The spectrometer measurements are also compared to predictions based on the beam current and on the produced rf power in the PETS, as well as particle tracking simulations with the Placet code.  
 
THPP036 CERN Linac4 Drift Tube Linac Manufacturing and Assembly 923
THPOL06   use link to see paper's listing under its alternate paper code  
 
  • S. Ramberger, P. Bourquin, A. Cherif, Y. Cuvet, A. Dallocchio, G. Favre, J.-F. Fuchs, J.-M. Geisser, F. Gerigk, J.-M. Giguet, J. Hansen, M. Polini, S. Sgobba, N. Thaus, M. Vretenar
    CERN, Geneva, Switzerland
  
  The manufacturing of the Linac4 Drift Tube Linac (DTL) components has been completed and the assembly of the structures is in its final stages. 3 tanks of 3.9m, 7.3m, and 7.3m, designed to accelerate a 40mA average pulse current H–beam from 3 to 50MeV, are being assembled from 2, 4 and 4 segments of about 2.0m length, containing each from 22 drift tubes at the low energy end, down to only 6 at the high energy end. Due to its peculiar design avoiding adjustment mechanisms on the drift tube, tight tolerances have to be maintained in the production. This paper discusses the assembly stages that are used to achieve the tolerances over the full length of the structures. Metrology results on the assembled DTL Tank1 confirm the required precision.  
 
THPP037 Commissioning and Operational Experience Gained with the Linac4 RFQ at CERN 926
THPOL02   use link to see paper's listing under its alternate paper code  
 
  • C. Rossi, L. Arnaudon, P. Baudrenghien, G. Bellodi, O. Brunner, J. Hansen, J.-B. Lallement, A.M. Lombardi, J. Noirjean
    CERN, Geneva, Switzerland
  • M. Desmons, A. France, O. Piquet
    CEA/DSM/IRFU, France
  
  The installation of Linac4 has started in 2013 with the 3 MeV Front End, aiming at delivering a fully commissioned 160 MeV H− beam by 2016. During summer 2013 the H− ion source, a clone of the first prototype, and the Low Energy Beam Transport lines have been installed in the Linac4 tunnel followed shortly by the Radiofrequency Quadrupole accelerator (RFQ), operating at the RF frequency of 352.2 MHz and which accelerates the ion beam to the energy of 3 MeV. The RFQ, which had already been commissioned at the 3 MeV Test Stand, was this time driven by a fully digital LLRF system. This paper reports the result of the bead-pull field check performed after the installation in the tunnel, the experience gained during recommissioning and the results of field characterization as a function of the water temperature in the RFQ cooling channels, showing how the accelerating field can be adjusted by simply tuning the different cavity modules.  
 
THPP038 The Drift Tube Welding Assembly for the Linac4 Drift Tube Linac at CERN 929
 
  • I. Sexton, A. Cherif, Y. Cuvet, G. Favre, J.-M. Geisser, S. Ramberger, S. Sgobba, T. Tardy
    CERN, Geneva, Switzerland
  • F.M. Mirapeix
    DMP, Mendaro, Spain
  
  The fabrication of the Linac4 Drift Tube Linac (DTL) required the welding assembly of 108 drift tubes (DT) which has been undertaken at the CERN workshop. The design of the DTL is particular in that it was purposely simplified to avoid any position adjustment mechanism for drift tubes in the tank. In consequence, drift tubes have been designed with tight tolerances and parts have been assembled with an optimised welding procedure. Two re-machining stages have been introduced in order to compensate for welding distortions. This paper discusses the various assembly stages with a view on the final precision that has been achieved.  
poster icon Poster THPP038 [8.665 MB]  
 
THPP039 Electron Beam Welding and Vacuum Brazing Characterization for SRF Cavities 932
 
  • N. Valverde Alonso, S. Atieh, I. Aviles Santillana, S. Calatroni, O. Capatina, L.M.A. Ferreira, F. Pillon, M. Redondas Monteserin, T. Renaglia, K.M. Schirm, T. Tardy, A. Vacca
    CERN, Geneva, Switzerland
  
  In the framework of the SPL R&D effort at CERN, development design efforts study the joining of dissimilar metals: bulk niobium for the superconducting RF cavities and stainless steel (316LN) or titanium alloys (Ti-6Al-4V and Nb55Ti) for the cryostats. Joining techniques of electron beam welding (EBW) and vacuum brazing are particularly important for these applications. These processes have been used in the accelerator community and developed into generally accepted “best practice”. Studies were performed to update the existing knowledge, and comprehensively characterise these joints via mechanical and metallurgical investigations using modern available technologies. The developed solutions are described in detail, some currently being applied uniquely at CERN.  
poster icon Poster THPP039 [5.324 MB]  
 
THPP040 A Compact High-Frequency RFQ for Medical Applications 935
 
  • M. Vretenar, A. Dallocchio, V.A. Dimov, M. Garlaschè, A. Grudiev, A.M. Lombardi, S.J. Mathot, E. Montesinos, M.A. Timmins
    CERN, Geneva, Switzerland
  
  In the frame of a new program for medical applications, CERN has designed and is presently constructing a compact 750 MHz Radio Frequency Quadrupole to be used as injector for hadron therapy linacs. The RFQ reaches an energy of 5 MeV in only 2 meters; it is divided into four standardized modules of 500 mm, each equipped with 12 tuner ports and one RF input. The inner quadrant radius is 46 mm and the RFQ has an outer diameter of 134 mm; its total weight is only 220 kg. The beam dynamics and RF design have been optimized for reduced length and minimum RF power consumption; construction techniques have been adapted for future industrial production. The multiple RF ports are foreseen for using either 4 solid-state units or 4 IOT’s as RF power sources. Although hadron therapy requires only a low duty cycle, the RFQ has been designed for 5% duty cycle in view of other uses. This extremely compact and economical RFQ design opens several new perspectives for medical applications, in particular for PET isotopes production in hospitals with two coupled high-frequency RFQs reaching 10 MeV and for Technetium production for SPECT tomography with two RFQs followed by a DTL.  
 
THPP041 The Accelerator Cryoplant at ESS 939
 
  • P. Arnold, J. Fydrych, W. Hees, J.M. Jurns, X. Wang, J.G. Weisend
    ESS, Lund, Sweden
  
  The European Spallation Source (ESS) is a neutron science facility funded by a collaboration of 17 European countries currently under design and construction in Lund, Sweden. Cryogenic cooling is vital particularly for the linear accelerator, producing a 5 MW beam of 2.0 GeV protons to strike a rotating tungsten target. The cryogenic section of the linac comprises cryomodules with superconducting RF cavities that require helium cooling at 2.0 K, shield cooling at ~40 K and liquid helium for power coupler cooling. An extensive cryogenic distribution system connects the cryomodules with the linac cryoplant. With estimated electricity consumption of up to 3 MW this plant will be one of the major power consumers at ESS. Turndown modes and the intrinsic uncertainties regarding heat loads drive the need for high plant efficiency not only during full load operation but also at reduced performance. Together with flexibility and reliability over a long operation period these are the key challenges that will be addressed in this paper.  
poster icon Poster THPP041 [4.141 MB]  
 
THPP042 Error Study on the Normal Conducting ESS Linac 942
SUPG007   use link to see paper's listing under its alternate paper code  
 
  • R. De Prisco, M. Eshraqi, R. Miyamoto, E. Sargsyan
    ESS, Lund, Sweden
  • A.R. Karlsson
    Lund University, Lund, Sweden
  
  One of the preliminary, but important test to evaluate the robustness of the accelerator design is performing the statistical error study by introducing realistic tolerances on the machine components. In this paper the guidelines to define the tolerances and the correction system are summarized in order to validate the design. Firstly statistical studies have been performed in order to define the sensitivity to single errors and to fix the tolerances. Then all errors, within the previous defined tolerances, are applied with the correction system to evaluate the beam quality and to check if the system guarantees a radiologically safe operation.  
 
THPP043 Benchmark of the Beam Dynamics Code DYNAC Using the ESS Proton Linac 945
THPOL11   use link to see paper's listing under its alternate paper code  
 
  • E. Tanke, R. De Prisco, M. Eshraqi, R. Miyamoto, A. Ponton, E. Sargsyan
    ESS, Lund, Sweden
  • S. Valero
    CEA, Gif-sur-Yvette, France
  
  The beam dynamics code DYNAC is benchmarked using the ESS Proton Linac. Recent work on improvements in the code, including of the RFQ model, is discussed. The three space charge routines contained in DYNAC, including a 3D version, have remained unchanged. The code contains a numerical method, capable of simulating a multi-charge state ion beam in accelerating elements. In addition, protons, single charge state heavy ions and non-relativistic electrons in accelerating elements can be modeled using an analytical method. The benchmark will include comparisons of both methods with the beam dynamics models in use at ESS: TraceWin and Toutatis. As this analytical method used in DYNAC is fast, it is a prime candidate for use as an online beam simulation tool.  
 
THPP044 ESS Normal Conducting Linac Status and Plans 948
 
  • A. Ponton, B. Cheymol, R. De Prisco, M. Eshraqi, R. Miyamoto, E. Sargsyan
    ESS, Lund, Sweden
  • G. Bourdelle, M. Desmons, A. France, O. Piquet, B. Pottin
    CEA/DSM/IRFU, France
  • I. Bustinduy, P.J. González, J.L. Muñoz, I. Rueda, F. Sordo
    ESS Bilbao, Bilbao, Spain
  • L. Celona, S. Gammino, L. Neri
    INFN/LNS, Catania, Italy
  • M. Comunian, F. Grespan, A. Pisent, C. R. Roncolato
    INFN/LNL, Legnaro (PD), Italy
  • P. Mereu
    INFN-Torino, Torino, Italy
  
  The ESS Normal Conducting (NC) linac is composed of an ion source, a Low Energy Beam Transport line, a Radio Frequency Quarupole (RFQ), a Medium Energy Beam Transport Line (MEBT) and a Drift Tube Linac (DTL). It creates, bunches and accelerates the proton beam up to 90 MeV before injecting into the superconducting linac which will deliver a 5 MW beam onto the neutron production target. The construction of the NC linac is part of a broad collaboration involving experts of various Labs in Europe. The technical chalenges and the collaboration strategy for the NC linac will be presented.  
 
THPP045 ESS Linac Beam Modes 951
 
  • E. Sargsyan, R. Miyamoto
    ESS, Lund, Sweden
  
  The ESS Linac will ultimately deliver 5 MW of beam power to the target with a long-pulse structure of 2.86 ms and 14 Hz repetition rate, which is essential for the production of long-wavelength neutrons [1]. Ten different beam power levels are requested for the operation. In order to preserve the required time structure of the beam, different beam power levels will be produced by reducing the beam current in ten regular steps using an iris with an adjustable aperture in the LEBT. Low current and low emittance beams may as well be useful for the beam commissioning of the Linac. This paper describes the generation and the beam dynamics of different beam modes in the ESS Linac.  
 
THPP046 SRF Highbay Technical Infrastructure for FRIB Production at Michigan State University 954
 
  • L. Popielarski, F. Casagrande, C. Compton, T. Elkin, A. Fila, P.E. Gibson, M. Hodek, L. Hodges, I.M. Malloch, C. Nguyen, R. Oweiss, J.P. Ozelis, J. Popielarski, C. Thronson, D.R. Victory, T. Xu
    FRIB, East Lansing, Michigan, USA
  • M. Leitner
    LBNL, Berkeley, California, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE- SC0000661
Michigan State University (MSU) has funded the construction of a new 27,000 square foot high bay building to house the Superconducting Radio Frequency (SRF) infrastructure for the Facility for Rare Isotope Beams (FRIB) production requirements. The construction has been completed and beneficial occupancy began on May 19th, 2014. The new SRF highbay includes over 4,000 square feet of cleanroom and chemistry facility space, automated cavity etch tools, ultra pure water systems, cold mass component inspection area, hydrogen degassing furnace, SRF testing capabilities for three vertical test Dewars and two horizontal cryomodule test bunkers with dedicated helium refrigeration system. The status of the technical equipment design, installation and commissioning will be presented. 		 
 
THPP047
 Integrated Testing of SRF Resonators with Couplers and Tuners in the Vertical Test Configuration at MSU  
 
  • J. Popielarski, S.K. Chandrasekaran, M. Hodek, D. Morris, J.P. Ozelis, L. Popielarski, K. Saito, N.R. Usher, D.R. Victory, Z. Zheng
    FRIB, East Lansing, Michigan, USA
  • A. Facco
    INFN/LNL, Legnaro (PD), Italy
  
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
A robust and extensive program of testing using the superconducting cavity vertical test facility at MSU has been used to validate cavities and ancillary systems for FRIB. The facility has been used to validate final designs of dressed HWR & QWR cavities with integrated tuners and LLRF control systems. In each test (QWR & HWR), the FRIB coupler is working at the full rated power at the full cavity field for long term operation integrated with the FRIB LLRF controller. The final validation of the SRF subsystems are achieved with long term stable lock with FRIB specified parameters for amplitude and phase control. Topics discussed include the dynamic loads of couplers and tuners, microphonics affects & QWR mechanical mode damping, and the model used to predict RF BW requirements for stable operation based on fundamental design parameters. 		 
 
THPP048 Design of a Compact Lever Slow/Fast Tuner for 650 MHz Cavities for Project X 957
 
  • I.V. Gonin, E. Borissov, T.N. Khabiboulline, Y.M. Pischalnikov, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Fermilab is developing 5-cell elliptical 650 MHz β=0.6 and β=0.9 cavities for Project X. A compact fast/slow lever tuner intended for both types of cavities has been developed for final tuning of the resonance frequency of the cavity after cooling down and to compensate the resonance frequency variations of the cavity during operation coming from liquid helium pressure fluctuations. The updated helium vessel (presented at this conference) is equipped with the tuner located at one of the end of the cavity. The tuner design and results of ANSYS analysis of their properties are presented.  
 
THPP049 Design of 162.5 MHz CW Main Coupler for RFQ 960
 
  • S. Kazakov, T.N. Khabiboulline, V. Poloubotko, O.V. Pronitchev, J. Steimel, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Project X Injector Experiment (PXIE) at Fermilab will utilize 162.5 MHz CW RFQ accelerating cavity. Design of new main power coupler for PXIE RFQ is reported. Two identical couplers are supposed to deliver approximately 100 kW total CW RF power to RFQ. Unique design of the coupler allows providing DC bias for multipactor suppression. Results of RF and thermal simulations along with mechanical design are presented.  
 
THPP050 Status of 325 MHz Main Couplers for PXIE 963
 
  • S. Kazakov, B.M. Hanna, T.N. Khabiboulline, V. Poloubotko, O.V. Pronitchev, L. Ristori, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  The Project X Injector Experiment (PXIE) at Fermilab will include one cryomodule with eight 325 MHz single spoke superconductive cavities (SSR1). Each cavity requires approximately 2 kW CW RF power for 1 mA beam current operation. A future upgrade will require up to 8 kW RF power per cavity. Fermilab has designed, procured and tested two prototype couplers for the SSR type cavities. Status of the 325 MHz main coupler development for PXIE is reported.  
 
THPP051 Design of a Quasi-Waveguide Multicell Deflecting Cavity for the Advanced Photon Source 966
 
  • A. Lunin, I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  • A. Zholents
    ANL, Argonne, Ilinois, USA
  
  This paper reports the electromagnetic design of a 2815 MHz Quasi-waveguide Multicell Resonator (called QMiR) being considered as a transverse RF deflecting cavity for the Advanced Photon Source’s (APS) Short Pulse X-ray project. QMiR forms a trapped dipole mode inside a beam vacuum chamber while High Order Modes (HOM) are heavily loaded. It results a sparse HOM spectrum, makes HOM couplers unnecessary and allows to simplify the cavity mechanical design. The form of electrodes is optimized for producing 2 MV of deflecting voltage and keeping low peak surface electric and magnetic fields of 54 MV/m and 75 mT respectively. Results of detailed EM analysis, including HOM damping at the actual geometry of beam vacuum chamber, will be presented.  
poster icon Poster THPP051 [1.250 MB]  
 
THPP052
 RF Control and DAQ Systems for Upgraded Vertical Test Facility at Fermilab  
 
  • Y.M. Pischalnikov, R.H. Carcagno, F.L. Lewis, R. Nehring, R.V. Pilipenko, W. Schappert
    Fermilab, Batavia, Illinois, USA
  
  Vertical Cavity Test Facility is major testing facility for extensive High Q0 SRF cavities R&D program at FNAL. Varieties of SRF cavities (325MHz, 650MHz, 1,3GHz and 3,9GHz ; bare and dressed) can be measured at VCTF. There are capabilities to cool-down cavities with slow & fast speed. Recently FNAL upgraded VCTF with two additional Vertical Test Stand (VTS2&3). Upgraded VCTF will be main R&D and production SRF cavities testing facility for new linear colliders (LCLS II and PIP II). We provide an overview of the design features, technical parameters and first operational experience of the newest RF control and DAQ systems, capable to serve three VTS (1,2&3).  
 
THPP053
 G4BeamLine, Design Tool for Multispecies Linacs  
 
  • M. Popovic
    Fermilab, Batavia, Illinois, USA
  
  The G4beamline program is a particle-tracking simulation program based on the Geant4 toolkit, optimized for beam lines and accelerating structures. This program can perform more realistic simulations than most alternatives, while being significantly easier to use by accelerator designers and physicists. This program has fostered the general acceptance within the muon community and the G4beamline user community has grown from about a half-dozen users to more than 300 users around the world.  
 
THPP054 Study of Coupler's Effect in Third Harmonic Section of LCLS-II SC Linac 969
 
  • A. Saini, A. Lunin, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  • T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  
  The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of 4 GeV superconducting (SC) linac which will use two stage bunch compression scheme in order to achieve short bunches with high peak current. In order to reduce non-linear effects in first bunch compressor, third harmonic section is utilized to linearize longitudinal phase space of the beam. However, transverse phase space of beam may get distorted due to coupler RF kicks and coupler wake kicks resulting from the asymmetry of input and HOM couplers in 3.9 GHz cavity. In this paper, we discuss coupler's effects and estimate resulting emittance dilution in third harmonic section. Local compensation of coupler kicks using different orientation of cavities are also addressed.  
 
THPP055 High Power Density Test of PXIE MEBT Absorber Prototype 973
 
  • A.V. Shemyakin, C.M. Baffes
    Fermilab, Batavia, Illinois, USA
  
  Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
One of the goals of the PXIE program at Fermilab is to demonstrate the capability to form an arbitrary bunch pattern from an initially CW 162.5 MHz H− bunch train coming out of an RFQ. The bunch-by-bunch selection will take place in the 2.1 MeV Medium Energy Beam Transport (MEBT) by directing the undesired bunches onto an absorber that needs to withstand a beam power of up to 21 kW, focused onto a spot with a ~2 mm rms radius. Two prototypes of the absorber were manufactured from molybdenum alloy TZM, and tested with a 28 keV DC electron beam up to the peak surface power density required for PXIE, 17W/mm2. Temperatures and flow parameters were measured and compared to analysis. This paper describes the absorber prototypes and key testing results. 		 
 
THPP056 Status of the Warm Front End of PXIE 976
 
  • A.V. Shemyakin, M.L. Alvarez, R. Andrews, C.M. Baffes, A.Z. Chen, R.T.P. D'Arcy, B.M. Hanna, L.R. Prost, G.W. Saewert, V.E. Scarpine, J. Steimel, D. Sun
    Fermilab, Batavia, Illinois, USA
  • R.T.P. D'Arcy
    UCL, London, United Kingdom
  • D. Li
    LBNL, Berkeley, California, USA
  
  Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
A CW-compatible, pulsed H− superconducting linac is envisaged as a possible path for upgrading Fermilab’s injection complex. To validate the concept of the front-end of such machine, a test accelerator (a.k.a. PXIE) is under construction. The warm part of this accelerator comprises a 10 mA DC, 30 keV H− ion source, a 2m-long LEBT, a 2.1 MeV CW RFQ, and a 10-m long MEBT that is capable of creating a large variety of bunch structures. The paper will report commissioning results of a partially assembled LEBT, status of RFQ manufacturing, and describe development of the MEBT, in particular, of elements of its chopping system. 		 
 
THPP057 Results of Cold Tests of the Fermilab SSR1 Cavities 979
 
  • A.I. Sukhanov, M.H. Awida, P. Berrutti, E. Cullerton, B.M. Hanna, A. Hocker, T.N. Khabiboulline, O.S. Melnychuk, D. Passarelli, R.V. Pilipenko, Y.M. Pischalnikov, L. Ristori, A.M. Rowe, W. Schappert, D.A. Sergatskov
    Fermilab, Batavia, Illinois, USA
  
  Fermilab is currently building the Project X Injector experiment (PXIE). The PXIE linac will accelerate a 1 mA H− beam up to 30 MeV and serve as a testbed for validation of Project X concepts and mitigation of technical risks. A cryomodule of eight superconducting RF Single Spoke Resonators of type 1 (SSR1) cavities operating at 325 MHz is an integral part of PXIE. Ten SSR1 cavities were manufactured in industry and delivered to Fermilab. We discuss tests of nine bare SSR1 cavities at the Fermilab Vertical Test Stand (VTS). Recently, one of the SSR1 cavities was welded inside a helium jacket. Results of the test of this cavity in the Fermilab Spoke Test Cryostat (STC) are shown. We report on the measured performance parameters of SSR1 cavities achieved during the tests.  
 
THPP058 A Review of Emittance Exchanger Beamlines: Past Experiments and Future Proposals 982
THPOL12   use link to see paper's listing under its alternate paper code  
 
  • J.C.T. Thangaraj
    Fermilab, Batavia, Illinois, USA
  
  Emittance exchangers (EEX) are advanced phase space manipulation schemes where the transverse phase space of the electron beam is exchanged with the longitudinal phase space. The first experimentally demonstrated concept of the emittance exchanger at the A0 photoinjector at Fermilab used a transverse deflecting cavity (TDC) sandwiched between two doglegs. In this talk, I will briefly review the history of the emittance exchange beamline experiments from a low charge beam without RF chirp to a high charge beam with RF chirp including collective effects such as coherent synchrotron radiation. I will also describe how shaping application have been spawned based on EEX. I will then review future schemes that has been proposed and propose two additional schemes of EEX that can be implemented in existing modern linacs. As an example, we present an improved emittance exchanger scheme that uses a TDC sandwiched between two chicanes. The significant advantage of this scheme is that it allows the use of the expensive transverse deflecting cavity for diagnostics and still allows the flexibility to use the existing beamline either as a bunch compressor or an emittance exchanger.  
 
THPP059 Z-Shaper: A Picosecond UV Laser Pulse Shaping Channel at the Advanced Superconducting Test Accelerator 986
 
  • J.C.T. Thangaraj, D.R. Edstrom, A.H. Lumpkin, J. Ruan
    Fermilab, Batavia, Illinois, USA
  • B. Beaudoin
    UMD, College Park, Maryland, USA
  
  Many accelerator applications require a longitudinally shaped electron beam profile for studies ranging from THz generation to dielectric wakefield acceleration. An electron beam profile can be shaped through many techniques in both electron beam generation, such as with a DAZZLER or in ellipsoidal pulse generation, and beam transport, using an emittance exchanger or linearizing harmonic cavity. In this paper, shaping of a UV pulse with length on the order of picoseconds is examined using alpha-BBO crystals in the Advanced Superconducting Test Accelerator (ASTA) drive laser. A relatively economical solution to effect a predictable and tunable longitudinal bunch shape, profiles have been generated and observed using a Hamamatsu C5680 streak camera, and the results are compared with the analytical theory.  
 
THPP060 Effect of Cavity Couplers Field on the Beam Dynamics of the LCLS-II Injector 989
 
  • A. Vivoli, A. Lunin, A. Saini, N. Solyak
    Fermilab, Batavia, Illinois, USA
  • A.C. Bartnik, I.V. Bazarov, B.M. Dunham, C.M. Gulliford, C.E. Mayes
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • D. Dowell, Z. Li, T.O. Raubenheimer, J.F. Schmerge, T. Vecchione, F. Zhou
    SLAC, Menlo Park, California, USA
  • D. Filippetto, R. Huang, C. F. Papadopoulos, H.J. Qian, S.P. Virostek, R.P. Wells
    LBNL, Berkeley, California, USA
  
  LCLS-II is a new light source based on a continuous wave (cw) superconducting linac to be built at SLAC. The Injector section of the linac creates the elecron beam and accelerates it up to about 100 MeV. The couplers of the accelerating cavities produce an asymmetric field resulting in a beam offset and, most importantly, in a significant transverse emittance dilution, if not compensated. In this paper we describe the simulations of the LCLS-II injector taking into account the cavity couplers effect and some mitigation techniques to reduce its impact on the beam quality.  
 
THPP061 RF Design of a Novel S-Band Backward Traveling Wave Linac for Proton Therapy 992
THPOL03   use link to see paper's listing under its alternate paper code  
 
  • S. Benedetti, U. Amaldi
    TERA, Novara, Italy
  • A. Degiovanni, A. Grudiev, W. Wuensch
    CERN, Geneva, Switzerland
  
  Proton therapy is a rapidly developing technique for tumour treatment, thanks to the physical and dosimetric advantages of charged particles in the dose distribution. Here the RF design of a novel high gradient accelerating structure for proton Linacs is discussed. The choice of a linear accelerator lies mainly in its advantage over cyclotron and synchrotron in terms of fast energy modulation of the beam, which allows the implementation of active spot scanning technique without need of passive absorbers. The design discussed hereafter represents a unicum thanks to the accelerating mode chosen, a 2.9985 GHz backward traveling wave mode with 150° phase advance, and to the RF design approach. The prototype has been designed to reach an accelerating gradient of 50 MV/m, which is more than twice that obtained before. This would allow a shorter Linac potentially reducing cost. The complete 3D RF design of the full structure for beta equal to 0.38 is presented. A prototype will be soon produced and tested at high power. This structure is part of the TULIP project, a proton therapy single-room facility based on high gradient linear accelerators.  
slides icon Slides THPP061 [1.537 MB]  
 
THPP062 BERLinPro SRF Gun Notch Filter Investigations 995
 
  • E.N. Zaplatin
    FZJ, Jülich, Germany
  • J. Knobloch, A. Neumann
    HZB, Berlin, Germany
  
  BERLinPro is an approved ERL project to demonstrate energy recovery at 100 mA beam current by pertaining a high quality beam. These goals place stringent requirements on the SRF cavity (1300 MHz, β=1) for the photoinjector which has to deliver a small emittance 100 mA beam with at least 1.8 MeV kinetic energy while limited by fundamental power coupler performance to about 230 kW forward power. The RF and beam dynamics gun cavity features 1.4 λ/2 cell resonator. To protect a cathode housing from RF power propagation from the cavity cells and to reduce its component heating a high-frequency notch filter was investigated. We present results of different schemes of choke cell combinations to optimize filter parameters. The goal for the filter design was the RF power attenuation better than -30 dB in the wide frequency range.  
 
THPP063 Beam Diagnostics Layout for the FAIR Proton Linac 998
 
  • T. Sieber, M.H. Almalki, C. Dorn, J. Fils, P. Forck, R. Haseitl, W. Kaufmann, W. Vinzenz, M. Witthaus, B. Zwicker
    GSI, Darmstadt, Germany
  • C.S. Simon
    CEA/DSM/IRFU, France
  
  The planned proton Linac for FAIR (Facility of Antiproton an Ion Research) will be - additionally to the existing GSI UNILAC - a second injector for the FAIR accelerator chain. It will inject a 70 MeV, (up to) 70 mA proton beam with a nominal pulse length of 30 us into the SIS18. The beam diagnostics system for the proton Linac comprises nine current transformers for pulse current determination and fourteen BPMs for position, mean beam energy and relative current measurement. SEM-Grids and stepping motor driven slits will be used for profile as well as for emittance measurements. A wire-based bunch shape monitor is foreseen, additionally a bending magnet for longitudinal emittance determination during commissioning. Presently, main efforts are conducted concerning the BPM system. Detailed signal simulations with the finite element code CST are performed. An electronics board using digital signal processing is evaluated by detailed lab-based characterization and beam-based measurements at the UNILAC. In this paper we present the general layout and the status of the diagnostics systems as well as key results from our measurements and simulations.  
 
THPP064
 First CH Power Cavity for the FAIR Proton Injector  
 
  • R. M. Brodhage, G. Clemente, W. Vinzenz
    GSI, Darmstadt, Germany
  • U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The main acceleration of this room temperature linac will be provided by six CH cavities operated at 325 MHz. Each cavity will be powered by a 2.5 MW Klystron. For the second acceleration unit from 11.5 MeV to 24.2 MeV a 1:2 scaled model has been built. Low level RF measurements have been performed to determine the main parameters and to prove the concept of coupled CH cavities. In 2012, the assembly and tuning of the first power prototype was finished. Until then, the cavity was tested with a preliminary aluminum drift tube structure, which was used for precise frequency and field tuning. In 2013 the final drift tube structure has been welded inside the main tanks and the preparation for copper plating has taken place. This paper will report on the main tuning and commissioning steps towards that novel type of DTL and it will show the latest results measured on a fully operational and copper plated CH proton cavity.  
 
THPP065 Acceleration of Intense Flat Beams in Periodic Lattices 1001
 
  • L. Groening, C. Xiao
    GSI, Darmstadt, Germany
  • I. Hofmann
    TEMF, TU Darmstadt, Darmstadt, Germany
  
  Recently a scheme for creation of flat ion beams from linacs has been proposed to increase the efficiency of multi-turn-injection. The proof of principle experiment shall be performed at GSI in Summer 2014. Since the scheme requires charge stripping, it may be necessary to perform the round-to-flat transformation prior to acceleration to the final energy of the linac. This requires preservation of the beam flatness during acceleration along the drift tube linac. This contribution is on simulations of acceleration of flat beams subject to considerable space charge tune depression. It is shown that the flatness can be preserved if the transverse tunes are properly chosen and if mis-match along inter-tank sections is minimized along the DTL.  
 
THPP067 Status of the SPP RFQ Project 1004
 
  • G. Turemen, B. Yasatekin
    Ankara University, Faculty of Sciences, Ankara, Turkey
  • A. Alacakir
    TAEK, Ankara, Turkey
  • G. Unel
    UCI, Irvine, California, USA
  • H. Yildiz
    Istanbul University, Istanbul, Turkey
  
  The SPP project at TAEA will use 352.2 MHz 4-vane Radio Frequency Quadrupole (RFQ) to accelerate H+ ions from 20 KeV to 1.5 MeV. With the design already complete the project is at the test production phase. To this effect, a so called "cold model" of 50cm length has been produced to validate the design approach, to perform the low power RF tests and to evaluate possible production errors. This paper will report on the current status of the low energy beam transport line (LEBT) and RFQ cavity of the SPP project. It will also discuss the design and manufacturing of the RF power supply and its transmission line. In addition, the test results from some of the LEBT components will be shown and the final RFQ design will be shared.  
poster icon Poster THPP067 [6.947 MB]  
 
THPP068 Cold Power Tests of the SC 325 MHz CH-Cavity 1007
SUPG012   use link to see paper's listing under its alternate paper code  
 
  • M. Busch, M. Amberg, F.D. Dziuba, H. Podlech, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • M. Amberg
    HIM, Mainz, Germany
  
  Funding: Work supported by GSI, BMBF Contr. No. 06FY7102
At the Institute for Applied Physics (IAP), Frankfurt University, a superconducting 325 MHz CH-Cavity has been designed, built and first tests have successfully been performed. The cavity is determined for a 11.4 AMeV, 10 mA ion beam at the GSI UNILAC. Consisting of 7 gaps this resonator is envisaged to deliver a gradient of 5 MV/m. Novel features of this structure are a compact design, low peak fields, improved surface processing and power coupling. Furthermore a tuner system based on bellow tuners driven by a stepping motor and a piezo actuator and attached inside the resonator will control the frequency. In this contribution measurements executed at 4 K and 2 K at the cryo lab in Frankfurt will be presented. 		 
poster icon Poster THPP068 [1.449 MB]  
 
THPP069 Status and Outlook of the 325 MHz 4-Rod RFQ 1010
 
  • B. Koubek, H. Podlech, A. Schempp, J.S. Schmidt
    IAP, Frankfurt am Main, Germany
  
  In order to built a Radio Frequency Quadrupole (RFQ) at 325 MHz for the FAIR proton linac, a 4-rod structure has been investigated. The RF design, especially the dipole and fringe fields and higher order modes, has been studied with simulations. A prototype has been built and power tested to verify the simulation results and investigate the high power performance. This paper summarizes the results of the research concerning the 325 MHz 4-rod RFQ and gives an overview about the next steps in this project.  
 
THPP070 Alternative Compact LEBT Design for the FAIR Injector Upgrade 1013
 
  • K. Schulte, M. Droba, S. Klaproth, O. Meusel, D. Noll, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • S.G. Yaramyshev
    GSI, Darmstadt, Germany
  
  In order to provide high intensity and brightness of the uranium beam for the planned FAIR project, the existing High Current Injector (HSI) at GSI has to be upgraded*. A part of the upgrade program is the design and construction of a compact straight injection line into the 36 MHz Radio Frequency Quadrupole of the HSI. As an alternative to a conventional LEBT design consisting of magnetic systems such as solenoids or quadrupoles, the application of Gabor lenses has been investigated. The focusing force of the Gabor lens is created by the space charge of an electron cloud, confined by crossed magnetic and electric fields inside the lens volume. Therefore, the Gabor lens combines strong, electrostatic focusing with simultaneous space-charge compensation. In previously performed beam transport experiments at GSI a prototype Gabor lens has been tested successfully. Furthermore, the operation and performance of such a device in a real accelerator environment has been studied. In this contribution an alternative LEBT design will be discussed and an improved Gabor lens design will be presented.
*W. Barth et al., “HSI-Frontend Upgrade”, GSI Scientific Report, 2009 		 
 
THPP071 Proposal of a 325 MHz Ladder-RFQ for the FAIR Proton-Linac 1016
 
  • M. Schütt, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • R. M. Brodhage
    GSI, Darmstadt, Germany
  
  Funding: BMBF 05P12RFRB9
For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The first rf accelerator element is a 325 MHz RFQ accelerating from 95 keV to 3.0 MeV. RFQ’s beyond 300 MHz were realized in 4-Vane-type geometry so far. At IAP there is a tradition in 4-Rod-type RFQ development. This type of RFQ is dominating at lower frequencies. Very promising results have been reached with a ladder type-RFQ, which has been investigated during 2013. In comparison with a traditional 4-Rod RFQ approach the geometry is more convenient at high frequencies. We will show most recent 3D simulations of the frequency tuning possibilities and of a whole cavity demonstrating the power of a ladder type RFQ. An RFQ layout for the new FAIR proton injector will be shown. (see also R. Brodhage, U. Ratzinger, A. Almomani, “Design Study of a High Frequency Proton Ladder RFQ” , Proc. of the 2013 IPAC Conference, Shanghai, China, p. 3788.) 		 
 
THPP072 BERLinPro Booster Cavity Design, Fabrication and Test Plans 1019
 
  • A. Burrill, W. Anders, A. Frahm, J. Knobloch, A. Neumann
    HZB, Berlin, Germany
  • G. Ciovati, P. Kneisel, L. Turlington
    JLab, Newport News, Virginia, USA
  
  The BERLinPro project, a 100 mA, 50 MeV superconducting RF (SRF) Energy Recovery Linac (ERL) is under construction at Helmholtz-Zentrum Berlin for the purpose of studying the technical challenges and physics of operating a high current, c.w., 1.3 GHz ERL. This machine will utilize three unique SRF cryomodules for the injector, booster and linac module respectively. The booster cryomodule will contain three 2-cell SRF cavities, based on the original design by Cornell University, and will be equipped with twin 115 kW RF power couplers in order to provide the appropriate acceleration to the high current electron beam. This paper will review the status of the fabrication of the 4 booster cavities that have been built for this project by Jefferson Laboratory and look at the challenges presented by the incorporation of fundamental power couplers capable of delivering 115 kW. The test plan for the cavities and couplers will be given along with a brief overview of the cryomodule design.  
 
THPP073 Cavity Excitation of the Chopped Beam at the J-PARC Linac 1023
 
  • K. Futatsukawa
    KEK, Ibaraki, Japan
  
  In the J-PARC linac, the beam energy at the injection of the rapid-cycle synchrotron (RCS) was upgraded up to 400 MeV by the installation of 25 additional cavities, annular-ring coupled structure (ACS), in 2013. The initial frequency of RCS was shifted to 1.227 MHz because of the change the injection-beam velocity. At the linac, the beam is chopped as the comb-like structure with this frequency (intermediate-pulse) by the RF deflector. The component of this RCS frequency excited the PC1 mode of DTL2 and was the cause of the RF-control difficulty. Additionally, it could be confirmed that other chopping operations, which does not have specific intermediate-pulses for example, drove other modes. In this paper, I would like to introduce this phenomena and the counterplan as the RF control.  
 
THPP074 Superconducting Nano-Layer Coating Without Insulator 1026
 
  • T. Kubo
    KEK, Ibaraki, Japan
  
  Last year, we submitted a theoretical paper on a multilayered structure with a single superconductor layer and a single insulator layer formed on a bulk superconductor, where the magnetic field on the interface of the bulk superconductor were derived with a rigorous calculation of the magnetic field attenuation in the multilayered structure and the general formula for the vortex penetration field of the superconductor layer were computed in terms of the force acting on a vortex. Using the formulae, a combination of the thicknesses of superconductor and insulator layers that can realize the enhanced field limit can be found for any given materials. Then our results on optimum combinations of layer thicknesses and resultant field limits were reproduced by other group, where they carried out the same computation in terms of energy. To confirm these theoretical implications, experiments to measure vortex penetration fields of multilayered superconductors are planned. Theoretical studies to help the planned experiments are also in progress. In this presentation we will explain our ongoing experimental and theoretical studies.
T. Kubo, Y. Iwashita, T. Saeki, Applied Physics Letters 104, 032603 (2014);
proceedings of SRF 2013, Paris, France (2013), p. 427;
proceedings of IPAC13, Shanghai, China (2013), p. 2343. 		 
 
THPP075 Development of Superconducting Spoke Cavity for Electron Accelerators 1030
 
  • T. Kubo, T. Saeki
    KEK, Ibaraki, Japan
  • E. Cenni, H. Fujisawa, Y. Iwashita, H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
  • R. Hajima, M. Sawamura
    JAEA, Ibaraki-ken, Japan
  
  Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
We have launched a development program of a superconducting spoke cavity for electron acceleration, in order to realize a compact industrial-use X-ray source with the laser-Compton scattering. Efforts for optimizing a cavity design by the electromagnetic field simulation, tracking of multipactor electrons and mechanical property calculations have been continued so far. The optimization processes reached the final stage, and studies toward fabrication processes started. In this presentation, we will show results and processes of the optimization. Attempts to fabricate the spoke cavity, which have just begun, will also be presented. 		 
 
THPP077 Fast Tuner Performance for a Double Spoke Cavity 1034
 
  • N. Gandolfo, S. Bousson, S. Brault, P. Duchesne, P. Duthil, G. Olry, D. Reynet
    IPN, Orsay, France
  • C. Darve, M. Lindroos
    ESS, Lund, Sweden
  
  IPN Orsay is developing the low-beta double Spoke cavities cryomodule for the ESS. In order to compensate resonant frequency variations of each cavity during operation, a deformation tuner has been studied and two of them have been built. The typical perturbations are coming from LHe saturated bath pressure variations as well as microphonics and Lorentz force detuning (LFD). In this paper, the tuner performance of the double Spoke cavity is presented.  
 
THPP078 Troubleshooting and Performances of Type-B Spiral2 Series Cryomodule 1037
 
  • D. Longuevergne, F. Chatelet, C. Commeaux, N. Gandolfo, D. Grolet, C. Joly, J. Lesrel, R. Martret, G. Michel, G. Olry, L. Renard, A. Stephen, P. Szott
    IPN, Orsay, France
  
  SPIRAL2 aims at building a multi-purpose facility dedicated to nuclear physics studies, including the production of rich-neutrons isotopes. The multi-beam linear accelerator is composed of superconducting accelerating modules operating at 4.2K and warm focusing magnets. IPN Orsay is in charge of the high energy (Type-B) accelerating modules, each hosting two superconducting 88 MHz quarter-wave resonators made of bulk Niobium operating at an accelerating gradient of 6.5 MV/m (β=0.12). The first Type-B series cryomodule has been validated in April 2013. Since then, four additional cryomodules have been validated in a row showing a very high-quality and reliable assembly procedure. Some of encountered problems (tuner hysteresis, magnetic shielding,…) and associated solutions will be presented. Moreover, a comparison of cavity performances between vertical cryostat and cryomodule tests will be done.  
 
THPP079 Prototyping Progress of SSR1 Single Spoke Resonator for RAON 1
 
  • H.J. Cha, M.O. Hyun, D. Jeon, H.C. Jung, H.J. Kim
    IBS, Daejeon, Republic of Korea
  
  The fabrication of prototypes for four different types of superconducting cavities (QWR, HWR, SSR1, and SSR2) for the Korean heavy ion accelerator, “RAON” is in progress. In this presentation, we report the current status of the SSR1 cavity (β=0.3 and f=325 MHz) prototype fabrication based on the technical designs. The issues when forming the niobium cavities such as pressing, machining, electron beam welding are reviewed. The RF testing for the prototypes, which will be done in near future, is also discussed.  
 
THPP084 Cyclotron-Undulator Cooling of Electron Beams 1041
 
  • S.V. Kuzikov, I.V. Bandurkin, A.V. Savilov
    IAP/RAS, Nizhny Novgorod, Russia
  • A.V. Savilov
    NNGU, Nizhny Novgorod, Russia
  
  XFELs require high-quality electron beams which can be produced in damping rings. For XFEL, based on Compton scattering of laser light, instead of the damping ring we consider a new compact device where electrons move in the undulator with axial DC magnetic field. In this undulator electrons move near resonant condition, rotating with cyclotron frequency and wiggling at similar bounce frequency. Such undulator allows compensation of the initial velocity spread by perturbations of the longitudinal velocities caused by transverse wiggling. Calculation show that ~1% velocity spread of 5 MeV electron beam (typical for photoinjectors) can be reduced to ~0.01% at distance as long as 20 undulator periods. In the advanced scheme, where the described undulators alternate with sections of the cyclotron radiation, energy spread as small as 0.001% is reachable. Calculations show that this principle works also for high energy beams (100 MeV and more), where RF undulator instead of DC-magnet undulator is preferable.  
poster icon Poster THPP084 [0.713 MB]  
 
THPP085 The Prototype of the Proton Injector for the European Spallation Source 1044
 
  • L. Celona, L. Andò, G. Castro, S. Gammino, D. Mascali, L. Neri, G. Torrisi
    INFN/LNS, Catania, Italy
  
  The update of the design of the PS-ESS source and of its LEBT has been carried out in 2013 and the construction is now ongoing. The Ion Source will be able to provide a proton beam current larger than 70 mA to the 3.6 MeV RFQ. Several innovative solutions have been implemented in the redesign phase in order to cope with high-reliability/high-performance requirements of the ESS project. A flexible magnetic system will allow to investigate alternative configurations for future ion current upgrade of the machine based on the formation of a denser plasma. Innovative set-ups have been also explored for beam extraction, transport and chopping. Calculations have shown that space charge compensation up to 95 % is needed to preserve the low emittance in the low energy beam transfer line (LEBT). In order to obtain the optimal proton beam pulse rise and fall time – that should be 100 ns – we propose a LEBT chopping configuration that permits hundred nanosecond rise times despite the LEBT compensation needs few microseconds. The ongoing development of a 3D PIC code will be also described, that should allow predicting and tuning the beam pulse for different source/LEBT operative configurations.  
 
THPP086 ESS DTL Error Study 1047
 
  • M. Comunian, F. Grespan, A. Pisent
    INFN/LNL, Legnaro (PD), Italy
  
  The Drift Tube Linac (DTL) of the European Spallation Source (ESS) is designed to operate at 352.2 MHz with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period) and will accelerate a proton beam of 62.5 mA pulse peak current from 3.62 to 90 MeV. The error study is decisive to define the DTL manufacturing tolerances and to evaluate its robustness. In this paper the DTL performances are shown.  
 
THPP087 ESS DTL Design and Drift Tube Prototypes 1050
 
  • F. Grespan, M. Comunian, A. Pisent, M. Poggi, C. R. Roncolato
    INFN/LNL, Legnaro (PD), Italy
  • P. Mereu
    INFN-Torino, Torino, Italy
  
  The Drift Tube Linac (DTL) for the ESS accelerator will accelerate protons up to 62.5 mA average pulse current from 3.62 to 90 MeV. The 5 tanks composing the DTL are designed to operate at 352.2 MHz in pulses of 2.86 ms long with a repetition rate of 14 Hz. The accelerating field is around 3.1 MV/m, constant in each tank. Permanent magnet quadrupoles (PMQs) are used as focusing element in a FODO lattice. The empty drift tubes accommodate Electro Magnetic Dipoles (EMDs) and Beam Position Monitors (BPMs) in order to implement beam corrective schemes. A complete set of Drift Tubes is under construction that is BPM, EMD and PMQ types. These prototypes are aimed to validate the design with the involved integration issues of the various components, as well as the overall technological and assembly process. This paper presents the main mechanical choices and the status of the prototyping program of the Drift Tubes.  
 
THPP089 High Power Conditioning of Annular-Ring Coupled Structures for the J-PARC Linac 1053
THPOL07   use link to see paper's listing under its alternate paper code  
 
  • H. Ao, T. Ito, Y. Nemoto, H. Oguri, N. Ouchi, J. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
  • H. Asano
    Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan
  • Z. Fang, K. Futatsukawa, K. Nanmo, T. Sugimura
    KEK, Ibaraki, Japan
  
  The linac of Japan Proton Accelerator Research Complex (J-PARC), which is an injector to a 3-GeV synchrotron, comprised a 3-MeV RFQ, 50-MeV DTLs and 181-MeV Separated-type DTLs. From September 2013, 25 annular-ring coupled structure (ACS) cavities were additionally installed to increase the linac beam energy up to 400 MeV and achieve 1-MW beam power of the 3-GeV synchrotron. After installation work the high power conditioning was started from December 2013 and most of the ACS cavities were conditioned within three weeks. We passed through some troubles and finally finished conditioning all the cavities until the middle of January 2014. In this paper, we present the conditioning results and how to handle the issue in the conditioning process.  
slides icon Slides THPP089 [7.756 MB]  
 
THPP090 Longitudinal Measurement of Annular-Ring Coupled Structure Linac in J-PARC 1056
 
  • T. Maruta, Y. Liu
    KEK/JAEA, Ibaraki-Ken, Japan
  • A. Miura
    JAEA/J-PARC, Tokai-mura, Japan
  
  In the J-PARC linac, Annular-type Coupled Structure (ACS) linac was introduced for the beam energy extension to 400 MeV in year 2013. To measure the longitudinal property of the ACS, we measured acceptance in phase direction by synchronous phase scan method and confirm that the acceptance is consistent with that by 3D PIC simulation. Simultaneously, the output beam energy from ACS was measured by orbit displacement where the dispersion is large. In this presentation, we discuss the measurement method and results.  
 
THPP091 Installation and Performance Check of Beam Monitors for Energy Upgraded J-PARC Linac 1059
 
  • A. Miura, K. Hasegawa, H. Oguri, N. Ouchi
    JAEA/J-PARC, Tokai-mura, Japan
  • M. Ikegami
    FRIB, East Lansing, Michigan, USA
  • Y. Liu
    KEK/JAEA, Ibaraki-Ken, Japan
  • T. Maruta
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • T. Miyao
    KEK, Ibaraki, Japan
  
  An energy upgrade project has started to achieve the design beam power of 1 MW at the exit of the downstream synchrotron in the J-PARC Linac since 2009. In the upgraded project, a beam energy in the Linac has increased from present 181 MeV to 400 MeV using the additional 21 annular-ring coupled structure (ACS) cavities. The new beam monitors as the beam current monitors, the phase monitors, the beam position monitors, the transverse profile monitors (wire scanner monitors) and the longitudinal profile monitors (bunch shape monitors) for the part where the ACS cavities were installed were designed, fabricated and calibrated. Till the end of November, 2013, all beam monitors were completed to be installed. From the middle of December, we started the beam commissioning to achieve the beam energy as 400 MeV, as well as to confirm the beam monitor functioning. We achieved the 400 MeV beam acceleration at the middle of January, 2014 using newly installed beam monitors. This paper describes the beam monitor installation, calibration and the beam commissioning results of beam monitor functioning.  
 
THPP092 Development of Slow Neutron Accelerator for Rebunching Pulsed Neutrons 1062
SUPG019   use link to see paper's listing under its alternate paper code  
 
  • S. Imajo
    Kyoto University, Kyoto, Japan
  • Y. Fuwa, Y. Iwashita, R. Kitahara
    Kyoto ICR, Uji, Kyoto, Japan
  • T. Ino
    KEK, Ibaraki, Japan
  • M. Kitaguchi, H.M. Shimizu
    Nagoya University, Nagoya, Japan
  • K. Mishima
    ICEPP, Tokyo, Japan
  
  Low energy neutrons can be accelerated or decelerated by the technique of AFP-NMR with RF and gradient magnetic fields. The neutrons have magnetic moments, hence their potential energy are not cancelled before and after passage of magnetic fields and their kinetic energy change finally when their spins are flipped in the fields. Nowadays most measurements of the neutron electric dipole moment (nEDM) are carried out with ultra cold neutrons (UCN), whose kinetic energies are lower than about 300 neV, and with a small storage bottle to reduce the systematic errors. In such experiments highly dense UCNs are desired. The spallation neutron sources generate high-density neutrons, however, the pulsed neutrons with several velocities are diffused in guide tubes under long beam intervals. It is necessary to focus and rebunch UCN temporally upon the bottle by controlling their velocities in nEDM experiments at those facilities. We demonstrated such rebuncher and have been developed the advanced apparatus which makes it possible to handle broader energy range UCN. The design, measured characteristics, the experimental setup and the obtained results at J-PARC will be described.  
 
THPP093 Combined System of Optical Inspection and Local Grinder 1065
 
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  • H. Hayano, T. Kubo, K. Watanabe, Y. Yamamoto
    KEK, Ibaraki, Japan
  
  Optical inspections on superconducting accelerating tubes have been playing an important role on improving their accelerating gradients. Instead of treatments on whole cavity inner surfaces to eliminate the found defects on the surfaces, the local grinding method succeeds to remove them efficiently. A combined system of the optical inspection and the local Grinding machines are fabricated. The overview of the system will be presented.  
 
THPP094 The Heavy Ion Injector at the NICA Project 1068
THPOL04   use link to see paper's listing under its alternate paper code  
 
  • A.V. Butenko, D.E. Donets, E.E. Donets, A.D. Kovalenko, A.O. Sidorin, A. Tuzikov
    JINR/VBLHEP, Moscow, Russia
  • V. Aleksandrov, E.D. Donets, A. Govorov, V. Kobets, K.A. Levterov, I.N. Meshkov, V.A. Mikhaylov, V. Monchinsky, G.V. Trubnikov
    JINR, Dubna, Moscow Region, Russia
  • H. Hoeltermann, H. Podlech, U. Ratzinger, A. Schempp
    BEVATECH, Frankfurt, Germany
  • T. Kulevoy, D.A. Liakin
    ITEP, Moscow, Russia
  
  The general goals of the Nuclotron-based Ion Collider fAcility (NICA) project at JINR (Dubna) are providing of colliding beams for experimental studies of both hot and dense strongly interacting baryonic matter and spin physics. The experiments will be performed in collider mode and at fixed target. The first part of the project program requires the collisions of heavy nuclei up to 197Au79+ to be studied. The new heavy ion linac – HILac (Heavy Ion Linear Accelerator) will accelerate ions with q/A – values above 0.16 to 3.2 MeV/u is under manufacturing presently. The main features of HILac are described.  
 
THPP095 Design Study of Superconducting Linear Accelerator for Unstable Ion Beams in RISP 1071
 
  • J.G. Hwang, C. Kim, E.-S. Kim
    Kyungpook National University, Daegu, Republic of Korea
  • B.H. Choi, H. Jang, D. Jeon, H.J. Kim, H.J. Kim, I. Shin
    IBS, Daejeon, Republic of Korea
  • L. Lee
    KNU, Deagu, Republic of Korea
  
  The post accelerator of RAON can accelerate the unstable and stable ion beams up to 15 MeV/u for 132Sn16+ and 58Ni8+ for 16.5 MeV/u, which has the ratio of mass to charge, A/q, of 8.3. The unstable ion beam such as 132Sn16+ produced by an ISOL system has the large transverse and longitudinal emittances. The post-accelerator consists of post-LEBT, RFQ, MEBT and superconduction linac(SCL3 and we optimized acceptance and beam envelope based on the beam dynamics in the linac. The accelerated beam by post accelerator was transported by the post-to-driver transport (P2DT) line which consists of a charge stripper, two charge selection sections and a telescope section with the bunching cavities to the high energy linac(SCL2) and accelerated up to 200 MeV/u. In this presentation, we will show the criteria for the design of the post accelerator and result of beam tracking simulation from post-LEBT to end of high energy linac.  
 
THPP096 RF Coaxial Resonator for Investigating Multipactor Discharges on Metal and Dielectric Surfaces 1074
 
  • M. El Khaldi, W. Kaabi, P. Lepercq, Y. Peinaud
    LAL, Orsay, France
  
  Multipactor discharge is a phenomenon in which electrons impact one or more material surfaces in resonance with an alternating electric field. The discharge can occur for a wide range of frequencies, from the MHz range to tens of GHz, and in wide array of geometries if the impacted surface has a secondary electron emission (SEE) yield larger than one. The discharge can take place on a single surface or between two surfaces. A novel coaxial resonator to investigate two-surface multipactor discharges on metal and dielectric surfaces in the gap region under vacuum conditions has been designed and tested. The resonator is ~ 100 mm in length with an outer diameter of ~ 60 mm (internal dimensions). A pulsed RF source delivers up to 30 W average power over a wide frequency range 650-900 MHz to the RF resonator. The incident and reflected RF signals are monitored by calibrated RF diodes. An electron probe provides temporal measurements of the multipacting electron current with respect to the RF power. These experiments were successful in identifying multipacting and allowed us the evaluation of a home made sputtered titanium nitride (TiN) thin layers as a Multipactor suppressor.  
 
THPP097 3D Effects in RFQ Accelerators 1077
 
  • S.S. Kurennoy
    LANL, Los Alamos, New Mexico, USA
  
  RFQ accelerators are usually designed and modeled with standard codes based on electrostatic approximations. Recent examples show that this approach fails to accurately predict the performance for 4-rod RFQs: 3D RF effects near the vane ends can noticeably influence the beam dynamics. The same applies to any RFQ where the quadrupole symmetry is broken, e.g., 4-vane RFQ with windows. We analyzed two 201.25-MHz 4-rod RFQs – one recently commissioned at FNAL and a new design for LANL – using 3D modeling with CST Studio. In both cases the manufacturer CAD RFQ model was imported into CST. The electromagnetic analysis with MicroWave Studio (MWS) was followed by beam dynamics modeling with Particle Studio (PS). For the LANL RFQ with duty factor up to 15%, a thermal-stress analysis with ANSYS was also performed. The simulation results for FNAL RFQ helped our Fermilab colleagues fix the low output beam energy. The LANL RFQ design was modified after CST simulations indicated insufficient tuning range and incorrect output energy; the modified version satisfies the design requirements.  
 
THPP098 Vertical Electropolishing of Nb Coupon Cavity and Surface Study of the Coupon Samples 1080
 
  • V. Chouhan, Y.I. Ida, K.N. Nii, 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
  
  We have been carrying out vertical electropolishing (VEP) of 1.3 GHz Nb cavities for the ILC for 2 years. In this article we present VEP of a single cell Nb coupon cavity containing 6 Nb disk type coupons located at beam pipes, irises and equator positions of the cavity. VEP experiments were performed using our special ninja-cathode newly developed and a straight rod cathode in order to observe and compare the homogeneity of electropolishing (EP) and surface quality on the entire surface of the single cell cavity. EP current was measured for the individual coupons under different EP conditions in order to study the EP phenomenon on the different positions of the cavity. The surfaces of the coupons were analyzed by x-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX). This article describes VEP and surface analysis results in detail.  
 
THPP099 Status of Superconducting Cavity and Cryomodule Development at MHI 1084
 
  • T. Yanagisawa, H. Hara, N. Ikeda, K. Sennyu
    MHI, Hiroshima, Japan
  
  MHI's activities for ｓuperconducting accelerator are reported. MHI had developed several procedure and method of ILC cavity production for stable quality and cost reduction. And we had fabricated and installed cryomodules for ILC and ERL R&D. These activities are reported in detail.  
 
THPP100 Result of MHI 2-Cell Seamless Dumb-Bell Cavity Vertical Test 1087
 
  • K. Okihira, H. Hara, N. Ikeda, F. Inoue, K. Sennyu
    MHI, Kobe, Japan
  • R.L. Geng, R.A. Rimmer
    JLab, Newport News, Virginia, USA
  • E. Kako
    KEK, Ibaraki, Japan
  
  MHI have supplied several 9-cell cavities for STF (R&D of ILC project at KEK) and have been considering production method for stable quality and cost reduction, seamless dumb-bell cavity was one of them. We had fabricated a 2 cell seamless dumb-bell cavity for cost reduction and measured RF performance in collaboration with JLab, KEK and MHI. Surface treatment recipe for ILC was applied for MHI 2-cell cavity and vertical test was performed at JLab. The cavity reached Eacc=32.4MV/m after BCP and EP. Details of the result are reported.  
 
THPP102 On Nonlinear Dynamics of a Sheet Electron Beam 1090
 
  • H.Y. Barminova
    MEPhI, Moscow, Russia
  
  In collisionless approximation the nonlinear dynamics of a charged particle beam is studied. Nonlinear oscillations of the beam radius appear due to external and self-consistent nonlinear forces. To study such oscillations the model is applied based on the kinetic distribution function dependent on the particle motion integrals. The 4th-order equation for the beam radius is obtained. The numerical solutions of the equation are analyzed. The cases of strong and weak nonlinearities caused by the own beam fields are discussed. In the case of weak deviation of the beam parameters from equilibrium ones the effective emittance growth isn't observed.  
 
THPP103 Low Dose X-Ray Radiation Source for Angiography Based on Channeling Radiation Principle 1093
 
  • T.V. Bondarenko, Yu.D. Kliuchevskaia, S.M. Polozov
    MEPhI, Moscow, Russia
  
  Angiography is one of the most reliable and contemporary procedure of the vascular system imaging. X-ray spectrums provided by all modern medical angiographs are too broad to acquire high contrast images and provide low radiation dose at the same time. The new method of narrow X-ray spectrum achieving is based on the idea of channelling radiation application. The X-ray filters used in this method allows eliminating the high energy part of the spectrum and providing dramatic dose reduction. The scheme of the facility including the X-ray filter is discussed. The results of the spectrum analysis for the channelling radiation source and typical angiography X-ray tube are discussed. Doses obtained by the water phantom and contrast of the iodine agent image are also provided for both cases.  
 
THPP104 Simulation of the Electron Beam Dynamics in the Biperiodical Structure 1096
SUPG030   use link to see paper's listing under its alternate paper code  
 
  • Yu.D. Kliuchevskaia, T.V. Bondarenko, S.M. Polozov
    MEPhI, Moscow, Russia
  
  А biperiodical accelerating structure (BAS) with operating frequency 27 GHz for the 6 MeV compact radiotherapy electron accelerator is considered. The operating frequency 27 GHz allows to significantly reduce the facility sizes, unlike the S-, X- and C-band operating linacs. The optimal geometrical parameters of BAS necessary for π/2 mode were defined by means of accelerating and coupling cell tuning. The BAS coupler was also simulated. Results of the electron beam dynamics analysis in designed structure are also discussed.  
 
THPP105 Beam Dynamics Simulation for the 1 GeV High Power Proton Linac 1099
 
  • S.M. Polozov, V.S. Dyubkov, T. Kulevoy, A.V. Samoshin
    MEPhI, Moscow, Russia
  • G. Kropachev, T. Kulevoy
    ITEP, Moscow, Russia
  
  Funding: This work is supported in part by the Ministry of Science and Education of Russian Federation under contract No. 14.516.11.0084
The design of high energy and high power proton linacs for accelerating driven systems (ADS) is one of the accelerator technology frontiers. Such linacs are under developing in EU, Japan, PRC but not discussed in Russia previous fifteen years. The driver linac and the breeder conceptual designs were funded by the Ministry of Science and Education of Russian Federation in 2013. The 2 MeV RFQ linac was proposed as the first accelerating section. A number of RF focusing sections types (by RF crossed lenses, modified electrode profile RFQ, axi-symmetrical RF focusing) were discussed for medium energies. The conventional modular scheme linac based on spoke-cavities and 5-cell elliptical cavities was designed for higher energies. The results of beam dynamics simulation in this linac will present. 		 
 
THPP106
 High charge heavy ion production for DPIS  
 
  • M. Kumaki, Y. Fuwa, S. Ikeda
    RIKEN, Saitama, Japan
  • T. Kanesue, M. Okamura
    BNL, Upton, Long Island, New York, USA
  • M. Washio
    RISE, Tokyo, Japan
  
  We have studied intense heavy ion acceleration using direct plasma injection scheme (DPIS). The DPIS consists of a laser ion source and RFQ linac. The produced laser ablation plasma is transported to an RFQ directly and the high brightness heavy ion flux can be efficiently captured by the RF focusing force. In the scheme, one of the most important key issues is how to control the ablation plasma properties. Recently we have tried to use a sub nano second laser system and found that the depth of plasma surface layer, where the laser energy is absorbed, is too thin to heat the plasma. To overcome this issue, the laser beam is split into two beams and those reached at the same spot on the target surface with a few nano second time interval. We will report the experimental results of the new irradiation technique.  
 
THPP107 Study on Polishing Method of Nb Surface by Periodic Reverse Current Electrolysis With Alkali Solution 1102
 
  • M. Umehara
    Nomura Plating Co, Ltd., Osaka, Japan
  • H. Hayano, T. Saeki
    KEK, Ibaraki, Japan
  
  Currently, electropolising method is thought to be the best method for the final surface preparation of superconducting RF cavity to obtain high gradient. In this conventional electropolising method, the electrolyte is the mixture of fluoric and sulfuric acids. Therefore, the operation of this method is dangerous, and the equipment becomes expensive because all parts should be made of high density polyethylene or fluorocarbon resin to avoid metallic parts which suffers from corrosion by electrolyte. Moreover, sulfur is produced as byproduct in the electropolishing process and this causes degradation of cavity performance. In order to overcome these drawbacks, we studied new polishing method of Nb surface by periodic reverse current electrolysis with alkali solution which causes no sulfur and allows the usage of metallic parts to realize cost effective equipment. In the study, we performed experiment of Nb coupons by this new method and obtained as good surface roughness as conventional electropolishing method. In this article, we report the details of the study.  
 
THPP108 Status of New 2.5 MeV Test Facility at SNS 1105
 
  • A.V. Aleksandrov, M.S. Champion, M.T. Crofford, Y.W. Kang, A.A. Menshov, R.T. Roseberry, M.P. Stockli, A. Webster, R.F. Welton, A.P. Zhukov
    ORNL, Oak Ridge, Tennessee, USA
  • K. Ewald
    Fermilab, Batavia, Illinois, USA
  • M.E. Middendorf, S.N. Murray, R.B. Saethre
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  Funding: Oak Ridge National Laboratory is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy
A new 2.5Mev beam test facility is being built at SNS. It consists of a 65 keV H− ion source, a 2.5MeV RFQ, a beam line with various beam diagnostics and a 6 kW beam dump. The facility is capable of producing one-ms-long pulses at 60Hz repetition rate with up to 50mA peak current. Commissioning with reduced average beam power is planned for fall 2014 to verify operation of all systems. The full power operation is scheduled to begin in 2015. Status of the facilty will be presented as well as discussion of the future R&D program. 		 
 
THPP109 History of Cryomodule Repairs at SNS 1108
 
  • M.P. Howell, M. Doleans, D.L. Douglas, S.-H. Kim
    ORNL, Oak Ridge, Tennessee, USA
  • R. Afanador, B. DeGraff, B.S. Hannah, C.J. McMahan, T.S. Neustadt, S.W. Ottaway, J. Saunders, P.V. Tyagi, D.M. Vandygriff
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  The operation of the Superconducting linear accelerator (SCL) has matured and now averages less than one trip per day. The availability of the SCL including radiofrequency systems, high voltage converter modulators, controls, vacuum and other support systems over the last three years is approximately 98%. The SNS has been in operation for ten years including the commissioning period. In support of achieving the stability of operation, multiple cryomodule repairs have been performed. Repairs to cryomodules have included instruments, helium leaks, valve actuators, cavity tuners, insulating vacuum repairs and upgrades, power supplies, higher order mode (HOM) feedthroughs, coupler windows, and coupler cooling components. Performance degradation has been experienced in multiple cavities. This has been corrected by thermal cycling the cryomodules with the affected cavities. Only two cavities have displayed slight permanent degradation that could not be corrected by thermal cycling. Repairs made to the SNS cryomodule will be detailed in this paper.  
 
THPP112 Multipacting Optimization of a 750 MHz RF Dipole 1111
SUPG021   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.
Crab crossing schemes have been proposed to re-instate luminosity degradation due to crossing angles at the interaction points in next generation colliders to avoid the use of sharp bending magnets and their resulting large synchrotron radiation generation, highly undessirable in the detector region. The rf dipole has been considered for a different set of applications in several machines, both rings and linear colliders. We present in this paper a study of the effects on the multipacting levels and location depending on geometrical variations on the design for a crabbing/deflecting application in a high current (3/0.5 A), high repetition (750 MHz) electron/proton collider, as a matter to provide a comparison point for similar applications of rf dipoles. 		 
 
THPP113 Architecture Design for the SwissFEL LLRF System 1114
 
  • Z. Geng, M. Broennimann, I. Brunnenkant, A. Dietrich, F. Gärtner, A. Hauff, M. Jurcevic, R. Kalt, S. Mair, A. Řežaeizadeh, L. Schebacher, T. Schilcher, W. Sturzenegger
    PSI, Villigen PSI, Switzerland
  
  The SwissFEL under construction at the Paul Scherrer Institut (PSI) requires high quality electron beams to generate x-ray Free Electron Laser (FEL) for various experiments. The LLRF system is used to control the klystron to provide highly stable RF field in accelerator structures for beam acceleration. There are more than 30 RF stations in the SwissFEL accelerator with different frequencies (S-band, C-band and X-band) and different types of cavities (standing wave cavities and traveling wave structures). Each RF station will be controlled by a LLRF control node and all RF stations will be connected to the real-time network in the scope of the global beam based feedback system. High level applications and automation procedures will be defined to fit the LLRF control nodes into the global control applications for the accelerator operation. In order to handle the complexity of the LLRF system, the system architecture is carefully designed considering the external interfaces, functions and performance requirements to the LLRF system. The architecture design of the LLRF system will be described in this paper with the focus on the fast networks, digital hardware, firmware and software.  
 
THPP114 The SwissFEL RF Gun: Manufacturing and Proof of Precision by Field Profile Measurements 1117
 
  • U. Ellenberger, H. Blumer, M. Kleeb, L. Paly, M. Probst
    Paul Scherrer Institute, Villigen PSI, Switzerland
  • M. Bopp, A. Citterio, H. Fitze, J.-Y. Raguin, A. Scherer, L. Stingelin
    PSI, Villigen PSI, Switzerland
  
  The high brightness electron source for SwissFEL is an in-house built 2.6 cell normal-conducting RF gun which is scaled to the RF frequency of 2'998.8 MHz. The RF gun is capable of operating at 100 Hz repetition rate and produces electron bunches at the exit of the RF gun of an energy of 7 MeV. Key features of the RF gun are described and how they have been implemented in the manufacturing process. RF field measurements of the RF gun are presented to account for the mechanical precision reached after manufacturing. The RF gun has been thoroughly tested in the SwissFEL injector test facility.  
 
THPP115 PKU 2.45 GHz Microwave Driven H− Ion Source Performance Study 1120
 
  • T. Zhang, J.E. Chen, Z.Y. Guo, S.X. Peng, H.T. Ren, Y. Xu, J.F. Zhang, J. Zhao
    PKU, Beijing, People's Republic of China
  • A.L. Zhang
    University of Chinese Academy of Sciences, Beijing, People's Republic of China
  
  Funding: This work is supported by the National Science Foundation of China (Grant Nos. 11175009, 91126004 and 11305004)
　　In a high intensity volume-produced H− ion source, H− ion production processes are great affected by electron temperature and gas pressure distribution within the discharge chamber. The H-/e ratio within an extracted H− ion beam is much depended on the electron absorption within the extraction system. At Peking University (PKU), lots of experiments were carried out for better understanding H− processes and electron dump on our 2.45 GHz microwave driven Cs-free permanent magnet volume-produced H− source. Detail will be given in this paper.
Author to whom correspondence should be addressed. Electronic mail:
sxpeng@pku.edu.cn. 		 
poster icon Poster THPP115 [2.252 MB]  
 
THPP116 Performance of New Injector RILAC2 for Riken Ri-Beam Factory 1123
 
  • N. Sakamoto, M. Fujimaki, N. Fukunishi, Y. Higurashi, O. Kamigaito, H. Okuno, K. Suda, T. Watanabe, Y. Watanabe, K. Yamada
    RIKEN Nishina Center, Wako, Japan
  • R. Koyama
    SHI Accelerator Service Ltd., Tokyo, Japan
  
  New injector called RILAC2 was designed and constructed to provide intense uranium beams with A/q≈7 with an energy of 0.67 MeV/u which are injected to the succeeding ring cyclotron, RIKEN Ring Cyclotron, called RRC. After the last LINAC conference where the commissioning of the RILAC2 was reported, some modifications and improvements with RILAC2 have been made aiming at stable operation. Recently, transmission efficiency and stability of the beams have been improved and the average beam current more than 20 pnA for uranium 345 MeV/u acceleration has been realized. In this paper the modifications and improvements of the RILAC2 together with the present performance are reported.  
 
THPP118 Design of a New Superconducting Linac for the RIBF Upgrade 1127
 
  • K. Yamada, O. Kamigaito, N. Sakamoto, K. Suda
    RIKEN Nishina Center, Wako, Japan
  
  An upgrade plan for the RIKEN RI-Beam Factory[1] is under discussion, the objective being to significantly increase the uranium beam intensity. In the upgrade plan, the existing ring cyclotron called RRC[2] will be replaced by a new linac, mainly consisting of superconducting (SC) cavities. The new linac is designed to accelerate heavy ions with a mass-to-charge ratio of ~7, such as 238U35+, up to an energy of 11 MeV/u in the cw mode. The present injector linac, RILAC2[3], will be used for the low-energy end, and a short room-temperature (RT) section will be added to RILAC2, which will boost the beam energy up to 1.4 MeV/u. The succeeding SC section consists of 14 cryomodules, each of which contains four quater-wavelength resonators (QWRs) with two gaps operated at 73 MHz. A RT quadrupole doublet is placed in each gap between the cryomodules. The modular configuration of the SC section was optimized based on the first-order approximation for the transverse and longitudinal motions. The designs of SC QWR were carried out using CST Microwave Studio 2013. Further study is under way on the SC QWR including the mechanical considerations, and we also start a design of cryostats.
[1] Y. Yano, Nucl. Instr. Meth. B 261, 1009 (2007).
[2] Y. Yano, Proc. 13th Int. Cyclo. Conf., 102 (1992).
[3] K. Yamada et al., Proc. of IPAC'12, TUOBA02, 1071 (2012).
 		 
 
THPP119 Stabilization of Beam Performance due to Improvement of the Precise Temperature Regulation System of the SACLA Injector 1131
 
  • T. Asaka, T. Hasegawa, H. Maesaka, Y. Otake, K. Togawa
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  
  The temperature of rf cavities in the SACLA injector have to be precisely controlled to generate stable electron beam for XFEL users. To maintain the rf voltage and phase in the each cavity, the temperatures of all the cavities were kept within 28±0.04˚C by controlling the cooling water temperature. AC power supply of the controller to heat the cooling water was operated at 2Hz by PWM control with alternatively tuning on and off. The correlation between beam position variation and a leakage magnetic field due to applying the heater current of an AC power supply was found out. Although the cooling water temperature was controlled less than ±40mK, the laser intensity was affected by slight temperature drift. Therefore, thermometer modules were replaced to more precise ones with 1mK resolution. A new temperature regulation system using a continuous level control with DC power supply was installed. The fast fluctuation of the magnetic field leak by the heater current due to the PWM control was removed. Consequently, the beam position jitter in an undulator section was reduced to less than one-third and the laser position variation was suppressed within 20μm.  
 
THPP120 Status of Radio-Frequency (RF) Deflectors at Radiabeam 1134
 
  • L. Faillace, R.B. Agustsson, J.J. Hartzell, A.Y. Murokh, S. Storms
    RadiaBeam, Santa Monica, California, USA
  
  Radiabeam Technologies recently developed an S-Band normal-conducting Radio-Frequency (NCRF) deflecting cavity for the Pohang Accelerator Laboratory (PAL) in order to perform longitudinal characterization of the sub-picosecond ultra-relativistic electron beams. The device is optimized for the 135 MeV electron beam parameters. The 1m-long PAL deflector is designed to operate at 2.856 GHz and features short filling time and femtosecond resolution. At the end of 2012, we delivered an X-band Traveling wave RF Deflector (XTD) to the ATF facility at Brookhaven National Lab. The device is optimized for the 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory, and is scalable to higher energies. The XTD is designed to operate at 11.424 GHz, and features short filling time, femtosecond resolution, and a small footprint. The XTD is currently being assembled at ATF for high-power operation and conditioning results will be reported soon.  
 
THPP121 Injector System for the IR-FEL at RRCAT 1137
 
  • L. Faillace, R.B. Agustsson
    RadiaBeam, Santa Monica, California, USA
  • A. Kumar, K.K. Pant
    RRCAT, Indore (M.P.), India
  
  An infrared (IR) free-electron laser (FEL) has been proposed to be built at the Raja Ramanna Centre for Advanced Technology (RRCAT). RadiaBeam is currently involved in the design of the RRCAT FEL's injector system. The injector will deliver an electron beam with a variable energy (from 15 up to 40 MeV) and 1.5 nC at 36.6 MHz repetition rate. We show here the beam dynamics of the beam transport through the injector as well as the RF design and mechanical model of the system.
* S. Krishnagopal et al., PRELIMINARY DESIGN OF THE PROPOSED IR-FEL IN INDIA, RRCAT, Indore, M.P. 452013, India 		 
 
THPP122 Development of Superconducting Cavities and Related Infrastructure for High Intensity Proton Linac for Spallation Neutron Source 1140
THPOL08   use link to see paper's listing under its alternate paper code  
 
  • S.C. Joshi, J. Dwivedi, P.D. Gupta, P.R. Hannurkar, V. Jain, P. Khare, P.K. Kush, G. Mundra, A. Puntambekar, S. Raghvendra, S.B. Roy, P. Shrivastava
    RRCAT, Indore (M.P.), India
  
  Raja Ramanna Centre for Advanced Technology has taken up a program on R&D activities of a 1 GeV, high intensity superconducting proton linac for a spallation neutron source. The proton linac will require a large number of superconducting Radio Frequency cavities ranging from low beta spoke resonators to medium and high beta multi-cell elliptical cavities at different RF frequencies. A dedicated facility is being set up for development of multi-cell superconducting cavities and their performance characterization. 1.3 GHz single-cell niobium cavities have been developed to establish the fabrication procedure. These cavities has exhibited high quality factor with an accelerating gradients up to 37 MV/m. A novel technique of laser welding of 1.3 GHz niobium cavity has been developed and demonstrated performance comparable to electron beam welded cavity. A dedicated facility for SCRF cavity forming, machining, electron beam welding, RF characterization, cavity tuning and cavity processing is being set up. To characterize a SCRF cavity at 2K, a vertical test stand has been developed and a horizontal test stand has been designed.  
 
THPP123 Experience of Operation of the Electron Linear Accelerator Based on Parallel Coupled Accelerating Structure 1144
 
  • A.E. Levichev, A.M. Barnyakov, D.A. Nikiforov
    BINP SB RAS, Novosibirsk, Russia
  • Y.D. Chernousov
    ICKC, Novosibirsk, Russia
  • V. Ivannikov, I.V. Shebolaev
    ICKC SB RAS, Novosibirsk, Russia
  
  An electron linear accelerator based on parallel coupled accelerating structure was developed and produced by Budker Institute of Nuclear Physics SB RAS and Institute of Chemical Kinetics and Combustion SB RAS. Short and long versions of the accelerating structure at 2450 MHz were built. For easy disassembly electrical and vacuum connections of the first (short) structure were made using indium seals. The second structure was brazed. Now the accelerator is in operation and used to study the accelerating and RF technologies. In the report the features of the accelerator are presented, including the design and characteristics of RF antenna and solid-state switch for the electron gun. Test results of the long parallel coupled accelerating structure are discussed. Observations made on the short structure surface after it had been opened are depicted. Now the short structure undergoes certain modifications in order to accelerate higher beam currents.  
 
THPP124 Wakefields in the Superconducting RF Cavities of LCLS-II 1147
 
  • K.L.F. Bane, T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  • A. Romanenko, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by Department of Energy contract DE–AC02–76SF00515.
The superconducting cavities in the linacs of LCLS-II are designed to operate at 2K, where cooling costs are very expensive. In addition to an unavoidable static load and the dynamic load of the fundamental 1.3 GHz accelerating rf, there will be higher order mode (HOM) power deposited by the beam. Due to the very short bunch length the LCLS-II beam spectrum extends into the THz range. Ceramic absorbers, cooled to 70K and located between cryomodules, are meant to absorb much of this power; understanding their effectiveness, however, is a challenging task. In this report we calculate the amount of power radiated by the beam in the different portions of the linac as the bunch length is changed by the bunch compressors. We consider both the steady state radiation as well as transients that arise at the beginning of the linac structures. In addition, transitions due to changes in the vacuum chamber aperture at the ends of the linacs are also considered. Finally, under the assumption that all the wake power ends up in the SRF cavity walls, we estimate the wall heating and the possibility of breaking the Cooper pairs and quenching the cavities. 		 
 
THPP125 Super-Compact SLED System Used in the LCLS Diagnostic System 1151
 
  • J.W. Wang, S.G. Tantawi, C. Xu
    SLAC, Menlo Park, California, USA
  
  Funding: * Work supported by Department of Energy contract DE–AC03–76SF00515.
At SLAC, we have designed and installed an X-band radio-frequency transverse deflector system at the LCLS for measurement of the time-resolved lasing effects on the electron beam and extraction of the temporal profile of the pulses in routine operations. We have designed an X-Band SLED system capable design to augment the available klystron power and to double the kick. 		 
 
THPP126 Design of the High Repetition Rate Photocathode Gun for the CLARA Project 1155
 
  • B.L. Militsyn, L.S. Cowie, P. Goudket, J.W. McKenzie, A.E. Wheelhouse
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G. Burt
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • T.J. Jones
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • V.V. Paramonov, A.K. Skasyrskaya
    RAS/INR, Moscow, Russia
  
  The CLARA injector is required to deliver ultrashort singe electron pulses with a charge of 250 pC following with a repetition rate of 100 and/or 400 Hz. It should also provide 2 us trains of twenty 25 pC pulses with a repetition rate 100 Hz. To meet this challenge, a 1.5 cell S-band photocathode gun with a field of up to 120 MV/m and coaxial coupling has been chosen. The length of the first cell of 0.5 is decided on the basis of beam dynamic simulation with the goal to obtain optimal for CLARA parameters. In order to improve amplitude and phase stability of the RF field, the gun is equipped with RF probes, which will provide feedback to the RF system. The gun and coupler were designed to accept up to 10 MW peak and 10 kW average RF powers. Cooling will be achieved by water channels cut into the bulk of the copper. The coupler will transition from waveguide to coax using an innovative H-shaped dual feed system that cancels out any dipole mode components and allows tuning of the match. The RF and mechanical design of the CLARA high brightness photocathode gun along with beam dynamics simulations are presented in this paper.  
 
THPP127 The Status of the Construction of MICE Step IV 1159
 
  • S. Ricciardi
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  
  Funding: NSF, DOE, STFC, INFN and more
The International Muon Ionisation Cooling Experiment in its next step IV will provide the first precise measurements of emittances and first evidence of cooling in 2015. The pair of MICE "emittometers" must be in place for this, upstream and downstream of the ionization cooling module. Each required the construction of a tracker (sci-fibers) measuring muon helices in solenoid coils that surround it. Solenoid coils confine muons to spiral in all components of a ionization cooling module. The first of these, that is now ready for Step IV, will be the first of three AFC (absorber-focus coil) modules: a Li-H vessel inside its own FC "focusing" coils. Li-H and other simpler, possibly competitive, liquid and solid absorber samples are also being prepared. The assembly process is in progress. Construction, performances, lessons learned will be described. Final step V and step VI demonstration requires two more AFC modules and two re-acceerating modules, RFCC's made of RF cavities inside their own focusing CC ("coupling" coils). The choices made and challenges being faced in this longer term construction efforts simultaneosly in progress will also briefly be pointed to.
The abstract is submitted by the chair of the MICE Speakers Bureau.
The presentation would be delivered by Dr Stefania Ricciardi (RAL)
Promotion to Oral would be most welcome 		 
 
THPP128
 The optimization of C-band RF pulse compressor for SXFEL linac at SINAP  
 
  • C.P. Wang, W. Fang, Z.T. Zhentang
    SINAP, Shanghai, People's Republic of China
  
  RF output of klystron and RF requirements of accelerator structure are two key factors for design of RF pulse compressor. According to these two factors, we can select the appropriate parameters and operating mode for optimizing RF pulse compressor cavity. And a general method of optimizing RF pulse compressor is summed in this paper, and using this method one precept of the C-band SLED type RF pulse compressor using TE0111 mode as the resonant cavity storage model is designed and studied at Shanghai Institute of Applied Physics, Chinese Academy of Science. By comparing the C-band RF pulse compressor using TE0115 mode as the resonant cavity storage model, the new precept have advantage of decreasing of the size of the resonant cavity, therefore it could save the installation space, reduce the construction cost and processing easily. Meanwhile it remains the high power gain and the large efficiency of C-band RF pulse compressor, and it also has no influence for the power requirement of the C-band accelerator structure at the Shanghai soft X-ray FEL facility.  
 
THPP129 Carbon Field Emission Strip Cathode Electron Source 1
 
  • T.V. Bondarenko, A.I. Botyachkova, G.G. Karpinskiy, S.A. Polikhov, G.B. Sharkov
    Siemens Research Center, Moscow,, Russia
  • A.I. Botyachkova, G.G. Karpinskiy
    National Research Nuclear University (MEPhI), Moscow, Russia
  • A.E. Geisler, O. Heid
    Siemens AG, Erlangen, Germany
  
  Over the recent years carbon nanostructure cathodes have become promising as a high brightness electron sources with large working area for field emission structures. Measurements and calculations of a field emission strip cathode based on carbon structure and a unit for its investigation are presented in the article. For measuring of the cathode emitting properties and determination of the electrons initial parameters used in the electron beam computer simulation the experimental setup is been developed. The setup consists of the high-voltage triode electrode system and allows to investigate the voltage-current characteristics of the cathode and to estimate the electron distribution of the beam on the anode surface. The anode electron distribution evaluations are processed by the measurements of the emitted X-ray focal spot on the anode by application of the CCD camera. Verification of the simulated electron beam dynamics can be obtained by application of the experimentally acquired data.  
poster icon Poster THPP129 [4.088 MB]  
 
THPP130 Development of FPGA-based Predistortion-type Linearization Algorithms for Klystrons within Digital LLRF Control Systems for ILC-like Electron Accelerators 1162
 
  • M. Omet
    Sokendai, Ibaraki, Japan
  • B. Chase, P. Varghese
    Fermilab, Batavia, Illinois, USA
  • T. Matsumoto, S. Michizono, T. Miura, F. Qiu
    KEK, Ibaraki, Japan
  
  Two different kinds of predistortion-type linearization algorithms have been implemented and compared on an FPGA within the digital LLRF control system the Advanced Superconducting Test Facility (ASTA) at the Fermi National Accelerator Laboratory (FNAL). The algorithms are based on 2nd order polynomial functions and lookup tables with interpolation by which complex correction factors are obtained. The algorithms were tested in an actual setup including a 5 MW klystron and a superconducting 9-cell TESLA-type cavity at ASTA. By this a proof of concept was demonstrated.  
poster icon Poster THPP130 [2.411 MB]  
 
THPP131 Series Superconducting Cavity Production for the HIE-ISOLDE Project at CERN 1165
 
  • M. Therasse, L. Alberty, K. Artoos, S. Calatroni, O. Capatina, A. D'Elia, N.M. Jecklin, Y. Kadi, I. Mondino, K.M. Schirm, A. Sublet, W. Venturini Delsolaro, P. Zhang
    CERN, Geneva, Switzerland
  
  In the context of the HIE-ISOLDE linac upgrade at CERN, the phase 1 planned to boost the energy of the machine from 3 MeV/u to 5 MeV/u. For this purpose, it is planned to install 2 cryomodules based on quarter waves resonators (QWRs) made by Niobium sputtering on Copper. The poster will present the different steps of the cavity series production since the reception from the industry to the cavity storage before cryomodule assembly. We will describe the cavity preparation included the resonance frequency measurement, the chemical treatment, the cavity rinsing, the Niobium coating and the RF test at 4.5K.  
 
THPP132 Warming Rate Reduction of the SARAF RF Couplers by Application of a High Voltage Dc Bias 1168
SUPG024   use link to see paper's listing under its alternate paper code  
 
  • B. Kaizer, Y. Ben Aliz, I. Fishman, J. Rodnizki, L. Weissman
    Soreq NRC, Yavne, Israel
  
  Warming up of the coupler region of the SARAF Half Wave Resonator (HWR) cavities was one of the main limiting factors for long operation at high RF field values. The warming effect is, most likely, associated with multipacting in the coupler region. We have tried to suppress the multipacting discharge in the couplers by application a DC bias to their inner conductors. A bias-T, element that conducts up to 4 kW of 176 MHz RF power and provides DC insulation of the coupler inner conductor, was designed and built for this purpose. First on-line operation showed that the DC bias indeed reduces dramatically the warming rates of most of the cavities by an order of magnitude. Today, coupler warming is no longer the main factor hindering accelerator operation.  
 
THPP133 LLRF System for the CEBAF Separator Upgrade 1171
 
  • T. E. Plawski, R. Bachimanchi, C. Hovater, D.J. Seidman, M.J. Wissmann
    JLab, Newport News, Virginia, USA
  
  The Continuous Electron Beam Accelerator Facility (CEBAF) energy upgrade from 6 GeV to 12 GeV includes the installation of four new 750 MHz deflecting, normal conducting cavities in the 5th pass extraction region. This system will work together with existing 499 MHz RF Separator in order to allow simultaneous delivery of the beam to four CEBAF experimental halls. The RF system employs two digital LLRF systems controlling four cavities in a vector sum. Cavity tune information of the individual cavities is also obtained using a multiplexing scheme of the forward and reflected RF signals. In this paper we will present detailed LLRF design and current status of the CEBAF 750 MHz beam extraction system.  
 
THPP135 Recent Improvements to Software Used for Optimization of SRF Linacs 1174
 
  • T. Powers
    JLab, Newport News, Virginia, USA
  
  Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
This work describes a software tool that allows one to vary parameters and understand the effects on the optimized costs of construction plus 10 year operations of an SRF linac. The program includes estimates for the associated cryogenic facility, and controls hardware, where operation costs includes the cost of the electrical utilities but not the labor or other costs. The software interface provides the ability to vary the cost of the different aspects of the machine as well as to change the cryomodule and cavity types. Additionally, this work will describe the recent improvements to the software that allow one to estimate the costs of energy recovery based linacs and to enter arbitrary values of the low field Qo and Qo slope. The initial goal was to convert a spreadsheet format to a graphical interface to allow the ability to sweep different parameter sets. The tools also allow one to compare the cost of the different facets of the machine design and operations so as to better understand the tradeoffs. An example of how it was used to investigate the cost optimization tradeoffs for the LCLS 2 linac will also be presented. 		 
 
THPP136 Study of Femtosecond Electron Bunch Generation at t-ACTS, Tohoku University 1178
THPOL01   use link to see paper's listing under its alternate paper code  
 
  • S. Kashiwagi, H. Hama, F. Hinode, A. Lueangaramwong, T. Muto, I. Nagasawa, S. Nagasawa, K. Nanbu, Y. Shibasaki, K. Takahashi, C. Tokoku
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • N.Y. Huang
    NSRRC, Hsinchu, Taiwan
  
  We are conducting a beam experiment of sub-picosecond electron bunch generation at a test accelerator as a coherent terahertz source (t-ACTS), Tohoku University. In the t-ACTS, the intense coherent terahertz radiation will be generated from an undulator and an isochronous accumulator ring based on the sub-picoseconds bunches. The accelerator is composed of a thermionic cathode rf gun, alpha magnet and 3 m-long accelerating structure. A velocity bunching scheme in accelerating structure is applied to generate the short electron bunch. The thermionic rf gun consists two independent cavities has been developed, which is capable of manipulating the beam longitudinal phase space. To produced femtosecond electron bunch, the longitudinal phase space distribution of the beam entering the accelerating structure is optimized by changing the rf gun parameters. The bunch length is measured by observing an optical tradition radiation with a streak camera. In the study of femtosecond electron bunch generation, a relation between the rf gun parameters and the bunch length after compression was investigated. The preliminary results of experiments will be described in this conference.  
 
THPP137 Present Status of the 3 MeV Proton Linac at Tsinghua University 1182
 
  • Q.Z. Xing, C. Cheng, C.T. Du, L. Du, T. Du, X. Guan, C. Jiang, C.-X. Tang, X.W. Wang, H.Y. Zhang, S.X. Zheng
    TUB, Beijing, People's Republic of China
  • W.Q. Guan, Y. He, J. Li
    NUCTECH, Beijing, People's Republic of China
  • B.C. Wang
    NINT, Xi'an, People's Republic of China
  
  We present, in this paper, the present status of the 3 MeV high current proton Linac for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. The ECR ion source produces 50 keV proton beam which is accelerated to 3 MeV by the downstream RFQ accelerator. The RFQ accelerator has been conditioned to 50 Hz/500 μs with the input power of 442 kW. Proton beam with the peak current of 30 mA, pulse length of 100 μs and repetition rate of 50 Hz has been delivered to the Beryllium target to produce the neutron since July 2013. The status of the development of the Drift Tube Linac is also presented in this paper. The beam energy will be enhanced to 13 MeV after the DTL is ready in 2015.  
 
THPP138 Measurements of Beam Current and Energy-Dispersion for Ion Beam with Multi-Components 1185
 
  • A.L. Zhang
    University of Chinese Academy of Sciences, Beijing, People's Republic of China
  • J.E. Chen, Z.Y. Guo, S.X. Peng, H.T. Ren, Y. Xu, T. Zhang, J. Zhao
    PKU, Beijing, People's Republic of China
  • J.E. Chen
    Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
  
  Funding: This work is supported by the National Science Foundation of China（Grant Nos. 91126004).
The multi-component ion beam is very common in nuclear physics, materials physics and most kind of ion source. But the diagnosis of multi-component ion beam [1] can be difficult because of its complex composition and irregular energy-dispersion. We need an effective way to analyzing the multi-component ion beam. There is a multi-component ion beam whose total beam current varies from 1 mA to 50mA and the beam energy can be 20keV to 150keV. In this paper, four methods to analyzing this multi-component ion beam are described, which are Faraday cup array method, fluorescent screen with Faraday cup, movable aperture with conductive fluorescent screen, and current calibration method, respectively. The distributions and currents of the separated ion beams are obtained by means of the four methods, and the current and energy-dispersion of each component might be measured at the same time. This is of special interest for beams with multi-components. Detailed description and comparison of the four methods are discussed in this paper.
Correspondence Author:Peng ShiXiang.
Email: sxpeng@pku.edu.cn 		 
poster icon Poster THPP138 [0.419 MB]  
 
THPP139 800MeV Linear Accelerator Development for HLS Upgrade 1189
 
  • K. Jin, Y. Hong, G. Huang, D. Jia, S.C. Zhang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Hefei Light Source (HLS) was mainly composed of an 800 MeV electron storage ring and a 200 MeV constant-impedance Linac functioning as its injector in NSRL PhaseⅠ. A new Linac has been developed successfully in view of the Full Energy Injection and the Top-up Injection scheme will be adopted in the HLS upgrade. In this paper, an 800MeV linear accelerating system construction, the constant-gradient structure with the symmetry couplers will be described in detail. The microwave system, the manufacture technology, the RF measurement, the high power testing and the accelerating system operation with beam currents are presented.  
 
THPP140 High Transparent Matched Window for Standing Wave Linear Accelerators 1192
 
  • A. Leggieri, F. Di Paolo, D. Passi
    Università degli Studi di Roma "Tor Vergata", Roma, Italy
  • A. Ciccotelli, G. Felici
    S.I.T., Aprilia, Italy
  
  This paper proposes a particular Dielectric Window (DW) for Standing Wave (SW) Linear Accelerators (LINAC’s). This study investigates the in-frequency return loss behavior of the LINAC, in order to improve matching and transmitting conditions while maintaining the optimum coupling between LINAC and High Power Microwave (HPMW) source. Device design is single-frequency based and considers the DW interface as an Input Matching Network (IMN) at the LINAC Normal Mode (NM) working frequency. Thus, design formulas are provided and Computer Aided Design (CAD) techniques are proposed. A prototype has been made and tested by performing cold S-parameter and Percentage Depth Dose (PDD) measurements of a LINAC with the proposed DW and with a traditional DW. The proposed device offers more energy transport attitude over the traditional DW, as shown by a return loss increase of 167% and an output electron energy increase of 5.5% while maintaining the same LINAC input power settings. This solution can offer a decrease of power line size, weight and cost. An after brazing global improvement of the accelerator figures of merit is also possible, as this study have demonstrated.
[1]Hiroyuki Arai, 1986
[2]K. Hirano, 1995
[3]Y. Otake, 1995
[5]A. Leggieri, 2014
[6]A. C. Ugural, 2003
[7]A. Leggieri, 2014
[8]F. Di Paolo, 2000
[9]N. Marcuvitz, 1951