Keyword: experiment
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MOIOB04 Current Status of PAL-XFEL undulator, gun, linac, electron 26
 
  • I.S. Ko, J.H. Han
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  The PAL-XFEL project aims to produce 0.1~nm coherent X-ray laser to photon beam users. In order to produce such photons, there are 10 GeV electron linac based on S-band normal conducting accelerating structures and a 150 m long out-vacuum undulator system. The project was already started in April 2011, and the 1.1 km long building is expected to be completed by December 2014. The injector test facility (ITF) which is for a test of the first 139 MeV section of the main linac has been installed and is in normal operation at the extension of the PLS linac building. In this paper, we introduce the project in general, a brief summary of site preparation and building construction, beam test results of ITF, and test results of subsystems produced by domestic manufacturers  
slides icon Slides MOIOB04 [9.901 MB]  
 
MOPP005 High Power Electron Accelerator Programme at BARC linac, electron, neutron, acceleration 58
 
  • K.C. Mittal, S. Acharya, R.I. Bakhtsingh, R. Barnwal, D. Bhattacharjee, S. Chandan, N. Chaudhary, R.B. Chavan, S.P. Dewangan, K.P. Dixit, S. Gade, L.M. Gantayet, S.R. Ghodke, S. Gond, D. Jayaprakash, M. Kumar, M.K. Kumar, H.K. Manjunatha, R.L. Mishra, J. Mondal, B. Nayak, S. Nayak, V.T. Nimje, S. Parashar, R. Patel, R.N. Rajan, P.C. Saroj, H.E. Sarukte, D.K. Sharma, V. Sharma, S.K. Srivasatava, N.T. Thakur, A.R. Tillu, R. Tiwari, H. Tyagi, A. Waghmare, V. Yadav
    BARC, Mumbai, India
  
  Bhabha Atomic Research Centre in India has taken up the indigenous design & development of high power electron accelerators for industrial, research and cargo-scanning applications. For this purpose, Electron Beam Centre (EBC) has been set up at Navi Mumbai, India. Pulsed RF Linacs, with on-axis coupled cavity configuration, include the 10 MeV Industrial RF linac, as well as 9 MeV linac and compact 6 MeV linac for cargo-scanning applications. Industrial DC accelerators include a 500 keV Cockroft-Walton machine and 3 MeV Dynamitron. Several radiation processing applications, such as material modification, food preservation, flue-gas treatment, etc. have been demonstrated using these accelerators. Cargo-scanning linacs have been successfully commissioned and are being characterized for the required x-ray output. A 30 MeV RF Linac, for research applications, such as shielding studies and n-ToF experiments, is being designed and developed. For ADS studies, a 100 MeV, 100 kW RF Linac system is proposed. This paper presents the details of the design of these accelerators, their development, current status and utilization for various applications.  
 
MOPP007 SF6 Gas Monitoring and Safety for DC Electron Beam Accelerator at EBC, Kharghar, Navi Mumbai electron, monitoring, high-voltage, operation 61
 
  • S.K. Suneet, S. Acharya, S. Banerjee, R. Barnwal, D. Bhattacharjee, N. Chaudhary, R.B. Chavan, K.P. Dixit, S. Gade, L.M. Gantayet, S.R. Ghodke, S. Gond, B.S. Israel, D. Jayaprakash, N. Lawangare, K. Mahender, R.L. Mishra, K.C. Mittal, B. Nayak, S. Nayak, R. Patel, R.N. Rajan, P.C. Saroj, D.K. Sharma, V. Sharma, M.K. Srvastava, D.P. Suryaprakash, N.T. Thakur, R. Tiwari, A. Waghmare
    BARC, Mumbai, India
  
  A 3 MeV, 30kW DC Industrial electron beam accelerator has been designed, commissioned and tested at Electron beam centre, Kharghar. The accelerator has been tested upto 5 kW power level with SF6 gas at 6 kg/cm2. The accelerating column, high voltage multiplier column, electron gun and its power supply are housed in accelerator tank, which is filled with SF6 gas as gaseous insulator at 6 kg/cm2. The SF6 gas is being used due to high dielectric strength and excellent heat transfer characteristics. The SF6 gas is non toxic and non carcinogenic. The SF6 gas replaces oxygen hence the TLV (threshold limiting value) is 1000 ppm for inhaled gas for persons working on the SF6 gas handling system. The SF6 gas is being green house gas, leak tightness has to monitor in the system and leak if any should be repaired. The gas should be used, recycled and reuse and thus saving the environment. This paper describes the safety and monitoring of the SF6 gas leak, quality and precautions in 3MeV accelerator.  
poster icon Poster MOPP007 [1.389 MB]  
 
MOPP015 High Energy Electron Radiography Experiment Research Based on Picosecond Pulse-width Bunch electron, linac, proton, quadrupole 76
 
  • Q.T. Zhao, S. Cao, R. Cheng, X.K. Shen, Z.M. Zhang, Y.T. Zhao
    IMP, Lanzhou, People's Republic of China
  • Y.-C. Du
    TUB, Beijing, People's Republic of China
  • W. Gai
    ANL, Argonne, Illinois, USA
  
  A new scheme is proposed that high energy electron beam as a probe is used for time resolved imaging measurement of high energy density materials, especially for high energy density matter and inertial confinement fusion. The first picosecond pulse-width electron radiography experiment was achieved by Institute of Modern Physics, Chinese Academy of Sciences and Tinghua University (THU), based on THU Linear electron accelerator (LINAC). It is used for principle test and certifying that this kind of LINAC with ultra-short pulse electron bunch can be used for electron radiography. The experiment results, such as magnifying factor and the imaging distortion, are consistent with the beam optical theory well. The 2.5 um RMS spatial resolution has been gotten with magnifying factor 46, with no optimization the imaging lens section. It is found that in the certain range of magnifying factor, the RMS spatial resolution will get better with bigger magnifying factor. The details of experiment set up, results, analysis and discussions are presented here.  
poster icon Poster MOPP015 [2.866 MB]  
 
MOPP023 X-band Technology for FEL Sources FEL, linac, emittance, operation 101
 
  • G. D'Auria, S. Di Mitri, C. Serpico
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • E. Adli
    University of Oslo, Oslo, Norway
  • A.A. Aksoy, O. Yavaş
    Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
  • D. Angal-Kalinin, J.A. Clarke
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • C.J. Bocchetta, A.I. Wawrzyniak
    Solaris, Kraków, Poland
  • M.J. Boland, T.K. Charles, R.T. Dowd, G. LeBlanc, Y.E. Tan, K.P. Wootton, D. Zhu
    SLSA, Clayton, Australia
  • G. Burt
    Lancaster University, Lancaster, United Kingdom
  • N. Catalán Lasheras, A. Grudiev, A. Latina, D. Schulte, S. Stapnes, I. Syratchev, W. Wuensch
    CERN, Geneva, Switzerland
  • W. Fang, Q. Gu
    SINAP, Shanghai, People's Republic of China
  • E.N. Gazis
    National Technical University of Athens, Athens, Greece
  • M. Jacewicz, R.J.M.Y. Ruber, V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  • X.J.A. Janssen
    VDL ETG, Eindhoven, The Netherlands
  
  As is widely recognized, fourth generation Light Sources are based on FELs driven by Linacs. Soft and hard X-ray FEL facilities are presently operational at several laboratories, SLAC (LCLS), Spring-8 (SACLA), Elettra-Sincrotrone Trieste (FERMI), DESY (FLASH), or are in the construction phase, PSI (SwissFEL), PAL (PAL-XFEL), DESY (European X-FEL), SLAC (LCLS II), or are newly proposed in many laboratories. Most of the above mentioned facilities use NC S-band (3 GHz) or C-band (6 GHz) linacs for generating a multi-GeV low emittance beam. The use of the C-band increases the linac operating gradients, with an overall reduction of the machine length and cost. These advantages, however, can be further enhanced by using X-band (12 GHz) linacs that operate with gradients twice that given by C-band technology. With the low bunch charge option, currently considered for future X-ray FELs, X-band technology offers a low cost and compact solution for generating multi-GeV, low emittance bunches. The paper reports the ongoing activities in the framework of a collaboration among several laboratories for the development and validation of X-band technology for FEL based photon sources.  
 
MOPP081 The ECT System for RAON's Cavities SRF, cavity, niobium, controls 242
 
  • M.J. Joung, Y. Jung, H.J. Kim
    IBS, Daejeon, Republic of Korea
  
  The ECT system is in use for Nb surface control in many laboratories. This system can inspect Nb surface quickly using high resolution. The ECT system for RAON's cavity was made with the feature : It has 3-axis acting probe movement system, It can inspect big size of Nb sheet, which is 1m by 1m and It contain the analysis program that can show the result as 2D and 3D image as well as relative figure of surface level. The standard sample was made with various sizes of defects using the same Nb sheet that was used to make RISP cavity. The ECT system conditioining was carried out to optimize ECT operation on the frequency, the range is from 300kHz to 2MHz. The result of 900 kHz shows the strongest signal. The conditioning experiment on other parameter will be carried out in near future. .  
 
MOPP091 Beam Test of a New RFQ for the J-PARC Linac rfq, linac, simulation, emittance 267
 
  • Y. Kondo, T. Morishita, Y. Sawabe, S. Yamazaki
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • T. Hori
    JAEA, Ibaraki-ken, Japan
  • A. Takagi
    KEK, Ibaraki, Japan
  
  We performed a beam test of a new 324-MHz 3-MeV RFQ (RFQ III) for the beam-current upgrade of the J-PARC linac. RFQ III is the first RFQ developed to meet the requirement of the J-PARC linac. The peak beam current is 50mA, pulse length is 500 micro-sec, and the repetition is 25 Hz. Before the installation to the accelerator tunnel scheduled in summer of 2014, we built a test stand for offline testing of the new ion source and RFQ. Basic performances of RFQ III such as transmission, transverse emittance, and energy spread were measured with short pulse length beams. In this paper, we present the results of the beam test.  
 
MOPP093 Evaluation of Beam Energy Fluctuations Caused by Phase Noises linac, timing, electron, cavity 273
 
  • H. Hanaki, H. Dewa, S. Suzuki, K. Yanagida
    JASRI/SPring-8, Hyogo-ken, Japan
  • T. Asaka, T. Ohshima
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  
  The SSB noises of the RF reference signal dominate the short-term instabilities of the RF phase of the carrier RF. This phase modulation finally results in beam energy fluctuation. This presentation gives a quantitative evaluation of the beam energy fluctuations in an electron linear accelerator caused by phase noises, comparing a theoretical analysis and experimental results. A simple model was introduced to understand how phase noises result in the relative phase difference between a beam bunch and accelerating RF fields. In the experiments, we measured the enhanced beam energy fluctuations by modulating the phase of the reference RF signals with an external signal. The interference between the accelerating RF phase modulation and the timing modulation of a beam bunch was found in the model analysis and also in the experimental results.  
 
MOPP096 Current Status of the Mainz Energy-Recovering Superconducting Accelerator Project linac, feedback, operation, diagnostics 282
 
  • M. Dehn, I. Alexander, K. Aulenbacher, J. Diefenbach, R.G. Heine, C. Matejcek, F. Schlander, D. Simon
    IKP, Mainz, Germany
  
  Funding: Work supported by the German Federal Ministery of Education and Research (BMBF) and German Research Foundation (DFG) under the Cluster of Excellence "PRISMA"
The Mainz Energy-Recovering Superconducting Accelerator (MESA) project at Johannes Gutenberg-Universtitaet Mainz has started in 2012 and is in full swing now. This presentation shows the current status of the project with a glance on cryogenics, superconducting RF, accelerator lattice design and the normal conducting injector. 		 
 
MOPP097 The Physics Programme of Next MICE Step IV emittance, scattering, solenoid, lattice 285
 
  • V. Blackmore
    JAI, Oxford, United Kingdom
  
  Funding: DOE, NSF, STFC, INFN and more
The international Muon Ionisation Cooling Experiment (MICE) is progressing toward a full demonstration of the feasibility of the cooling technology required for neutrino physics and muon colliders. Step IV will provide the first precise measurements of emittance and determine the influence of material properties on emittance reduction. The physics programme of the Step IV measurements is described in detail, along with a longer term view to demonstrating and studying (sustainable) ionisation cooling with re-acceleration.
The abstract is submitted by the chair of the MICE Speakers Bureau.
The presentation will be delivered by Dr Victoria Blackmore (Oxford)
Promotion to Oral presentation is be most welcome. 		 
 
MOPP108 Vertical Electro-Polishing of Nb Nine-Cell Cavity Using Cathode with Variable-Geometry Wings cavity, cathode, power-supply, status 307
 
  • K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
    KEK, Ibaraki, Japan
  • K. Ishimi
    MGI, Chiba, Japan
  
  Marui Galvanizing Co. Ltd. has been studying on Vertical Electro-Polishing (VEP) of Nb superconducting accelerator cavity for the mass-production and cost-reduction of Electro-Polishing (EP) process in collaboration with KEK. And we invented VEP process by a cathode with variable-geometry wings to get uniform distributions of both electric current and EP solution flow. Using this cathode, we performed various tests of VEP with Nb single-cell cavities. In this article, we will report fabrication of the first VEP facility for Nb nine-cell cavity and the VEP results using cathode with variable-geometry wings.  
 
MOPP110 Multipacting Prediction for the 106.1 MHz Quarter Wave Resonator simulation, cavity, ISAC, electron 313
 
  • M. Gusarova, I.I. Petrushina, E.A. Savin, A.N. Stolbikova
    MEPhI, Moscow, Russia
  • V. Zvyagintsev
    TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
  
  The results of analytical calculations and numerical simulations of multipacting in the 106.1 MHz Quarter Wave Resonator (QWR) are presented. Resonant voltages, impact energies and corresponding particle trajectories are obtained. In this paper we compare CST PS and MultP-M 3D simulation results for multipacting in the cavity.  
 
MOPP120 Beam Dynamic Design of a 100 mA, 162.5 Mhz High-Current Linac rfq, linac, emittance, quadrupole 336
 
  • F.J. Jia, J.E. Chen, Y.R. Lu, Z. Wang, W.L. Xia, X.Q. Yan, K. Zhu
    PKU, Beijing, People's Republic of China
  • W.P. Dou, Y. He
    IMP, Lanzhou, People's Republic of China
  
  Funding: This work is supported by the 973 program (No. 2014CB845503) and the NSFC (Grants No. 11079001).
The beam dynamic design of a 100 mA, 162.5 MHz Radio Frequency Quadrupole (RFQ) is presented in this paper. The RFQ will accelerate protons from 85 keV to 3 MeV under the operation mode of continuous-wave (CW). The code PARMTEQM is used to carry out the beam dynamics design and the transmission efficiency has been optimized and improved to more than 99%. In the design of this high-current linac, the space charge effect is analyzed as it can cause emittance growth, nonuniform particle density distribution and resonance effect. The electrode structure parameters generated by PARMTEQM also be adopted by the code of Toutatis to verify the result’s veracity. 		 
 
MOPP128 Bridging the Gap Between Conventional RF Acceleration and Laser Driven Acceleration electron, operation, acceleration, cyclotron 358
 
  • M.V. Fazio, V.A. Dolgashev, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  
  For decades conventional RF accelerators have been built and operated with ever increasing capability through a few tens of gigahertz in frequency. More recent research takes advantage of the continuing development of high peak power short pulse lasers to drive accelerator structures at optical frequencies. This jump from RF to optical frequencies skips four orders of magnitude in wavelength. With recent experiments that demonstrate high gradients in metallic structures at millimeter wavelengths one is compelled to consider the viability of new approaches for acceleration in the millimeter-wave to terahertz regime. This paper will explore some of these possibilities.  
 
MOPP133 Measurements of Cavity Misalignment by Beam Induced HOM Excited in 9-cell Superconducting Cavities HOM, cavity, simulation, dipole 370
 
  • A. Kuramoto
    Sokendai, Ibaraki, Japan
  • N. Baboi
    DESY, Hamburg, Germany
  • H. Hayano
    KEK, Ibaraki, Japan
  
  Detection of cavity misalignment in the ILC superconducting cavities inside of the cryomodules can be done by using beam induced Higher Order Modes (HOM). It is beneficial to identify possible source of emittance growth by cavity misalignment. Beam pipe modes which are localized in both ends of the cavity and TE111 1/9 pi mode which is localized in the center of the cavity are focused in this research. Deviations of these electrical centers from beam trajectory reference indicate cavity misalignment and bending. We measured beam-induced HOM in STF cavities of the STF accelerator at KEK in 2012 – 2013 and TESLA cavities of FLASH at DESY in 2013. We could identify beam pipe modes and TE111 1/9 pi mode in STF cavities and TESLA cavities at around 2.1 GHz and 1.6 GHz, both of which were very small signals. The electrical center of these beam pipe mode are studied by stretched wire method, beads perturbation method and simulations by CST MICROWAVE STUDIO 2012 and HFSS 12. In this paper, the results of these measurements and simulations are summarized.  
 
TUPP022 RF Tuning of a S-band Hybrid Buncher for Injector Upgrade of LINAC II at DESY linac, electron, simulation, target 478
 
  • Y.C. Nie, M. Hüning, C. Liebig, M. Schmitz
    DESY, Hamburg, Germany
  
  LINACII at DESY currently provides 450 MeV electrons for the synchrotron radiation source PETRAIII. The injector upgrade of it aims to improve its reliability and mitigate the radiological activation due to electron losses at hundreds of MeV. Therefore, a 2.998 GHz hybrid buncher has been developed and will be installed in between a pre-buncher and LINAC II. It comprises a 1-cell standing-wave (SW) section for rapid acceleration and a 13-cells travelling-wave (TW) section for further bunching and acceleration. This paper focuses on its rf tuning procedure. The tuning strategy combines a non-resonant bead-pull measurement of complex electric field and a linear model for local reflection coefficient calculation. The tuning result is satisfying. Field unflatness of the TW section has been improved from ±9% to ±4%, and field in the SW section has been enhanced significantly. By using ASTRA simulation, it has been verified that the residual detuning of the structure is acceptable in view of beam dynamics performance.  
 
TUPP028 Beam Tests at the CLIC Test Facility, CTF3 operation, emittance, linac, acceleration 487
 
  • R. Corsini, S. Döbert, W. Farabolini, D. Gamba, J.L. Navarro Quirante, T. Persson, P.K. Skowronski, F. Tecker
    CERN, Geneva, Switzerland
  • W. Farabolini
    CEA/DSM/IRFU, France
  • D. Gamba
    JAI, Oxford, United Kingdom
  
  The CLIC Test Facility CTF3 has been built at CERN by the Compact Linear Collider (CLIC) International Collaboration, in order to prove the main feasibility issues of the two-beam acceleration technology on which the collider is based. After the successful completion of its initial task, CTF3 is continuing its experimental program in order to give further indications on cost and performance issues, to act as a test bed for the CLIC technology, and to conduct beam experiments aimed at mitigating technological risks. In this paper we discuss the status of the ongoing experiments and present the more recent results, including improvements in beam quality and stability.  
 
TUPP031 Understanding the Error Tolerances Required to Automatically Phase the HIE-ISOLDE Linac emittance, linac, cavity, software 496
 
  • M.A. Fraser, J.C. Broere, S. Haastrup, D. Lanaia, D. Valuch, D. Voulot
    CERN, Geneva, Switzerland
  
  The broad experimental programme at ISOLDE means that the same radioactive beam species and energy are rarely studied twice and the cavities of the linac must be scaled or re-phased for each experiment. A software application was developed to automatically re-phase the cavities of the HIE-ISOLDE superconducting linac to the beam from computed settings. The application was developed to expedite both machine set-up in normal operation and in scenarios involving cavity failures. A beam dynamics error study will be presented in order to better understand the challenges facing the automatic phasing routine. The effects of a variety of different errors on the efficacy of the phasing application were studied, leading to a specification of the tolerances required for the calibration of the rf system and the accuracy of the survey system that monitors the positions of the cavities.  
 
TUPP033 Effect of Beam-Loading on the Breakdown Rate of High Gradient Accelerating Structures klystron, beam-loading, linac, acceleration 499
 
  • J.L. Navarro Quirante, R. Corsini, A. Degiovanni, S. Döbert, A. Grudiev, O. Kononenko, G. McMonagle, S.F. Rey, A. Solodko, I. Syratchev, F. Tecker, L. Timeo, B.J. Woolley, X.W. Wu, W. Wuensch
    CERN, Geneva, Switzerland
  • O. Kononenko
    SLAC, Menlo Park, California, USA
  • A. Solodko
    JINR, Dubna, Moscow Region, Russia
  • J. Tagg
    National Instruments Switzerland, Ennetbaden, Switzerland
  • B.J. Woolley
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • X.W. Wu
    TUB, Beijing, People's Republic of China
  
  The Compact Linear Collider (CLIC) is a study for a future room temperature electron-positron collider with a maximum center-of-mass energy of 3 TeV. To efficiently achieve such high energy, the project relies on a novel two beam acceleration concept and on high-gradient accelerating structures working at 100 MV/m. In order to meet the luminosity requirements, the break-down rate in these high-field structures has to be kept below 10 per billion. Such gradients and breakdown rates have been demonstrated by high-power RF testing several 12 GHz structures. However, the presence of beam-loading modifies the field distribution for the structure, such that a higher input power is needed in order to achieve the same accelerating gradient as the unloaded case. The potential impact on the break-down rate was never measured before. In this paper we present an experiment located at the CLIC Test Facility CTF3 recently proposed in order to quantify this effect, layout and hardware status, and discuss its first results.  
slides icon Slides TUPP033 [1.970 MB]  
poster icon Poster TUPP033 [2.355 MB]  
 
TUPP047 PXIE RFQ Bead Pull Measurements rfq, beam-transport, cavity, quadrupole 535
 
  • P. Berrutti, T.N. Khabiboulline, V. Poloubotko, G.V. Romanov, J. Steimel, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  • D. Li, J.W. Staples
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359
Project X Injector Experiment radio frequency quadrupole has recently been built for Fermilab by Berkley laboratory. This RFQ will be placed after the low energy beam transport (LEBT) and before the medium energy beam transport (MEBT). The RFQ will operate at 162.5 MHz in CW regime; its function is to accelerate and focus particles coming from the LEBT at 30 keV, and to deliver a beam at 2.1 MeV to the MEBT. In order to make sure that the RFQ meets the specifications of field flatness and frequency the field in the vanes should be measured using bead pull technique. FNAL created a new single wire bead pull set up for the RFQ of PXIE. The measurements are used to find the electrical center of the structure, then the amplitude of the electromagnetic field in all the sectors of the RFQ; and the tuning will be based on these measurements. This paper describes the bead pull experimental set up, the software developed for this particular application and the measurements taken. 		 
poster icon Poster TUPP047 [1.089 MB]  
 
TUPP071 Vortex-Penetration Field at a Groove with a Depth Smaller than the Penetration Depth cavity, framework, vacuum 590
 
  • T. Kubo
    KEK, Ibaraki, Japan
  
  Analytical models of the magnetic field enhancement at pits were presented at SRF2013 last year. In this presentation, I will show updated models.
proceedings of SRF 2013, Paris, France (2013), p. 430 		 
 
TUPP080 Commissioning of the MAX 700 MHz Test Stand cavity, cryomodule, controls, operation 610
 
  • J.-L. Biarrotte, F. Chatelet, M. El Yakoubi, N. Gandolfo, C. Joly, J. Lesrel, H. Saugnac
    IPN, Orsay, France
  • A. Bosotti, R. Paparella, P. Pierini
    INFN/LASA, Segrate (MI), Italy
  • F. Bouly
    LPSC, Grenoble Cedex, France
  • I. Martin-Hoyo
    ADEX, Madrid, Spain
  
  The MYRRHA project aims at the construction of an Accelerator Driven System demonstrator. The criticality will be sustained by an external spallation neutron flux produced thanks to a 600 MeV high intensity proton beam. This beam will be delivered by a superconducting linac which must fulfil very stringent reliability requirements. Under the MAX (MYRRHA Accelerator eXperiment) program, which aims at pursuing the R&D activities on the ADS-type accelerator, a 700 MHz Cryomodule was developed. The main goal of this test stand is to dispose of a facility to carry out “real scale” reliability oriented studies on a RF Superconducting cavity of the high-energy linac section. This module holds 5-cells elliptical cavity equipped with its blade cold tuning system and its coaxial power coupler. The experimental work undertaken at IPN Orsay, has allowed to fully qualify the module in machine configuration (high RF power, at 2K), including assessment of the tuning system and measurement of microphonics spectrums. During this study the dynamic behavior of the fast tuning system of the cavity was also measured. We review here the obtained results and lessons learnt by operating this module.  
 
TUPP101 Vertical Electro-Polishing of Nb Single-Cell Cavity Using Cathode with Variable-Geometry Wings and Its Results of Vertical Test cavity, cathode, power-supply, target 662
 
  • K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • P. Carbonnier, F. Éozénou, C. Servouin
    CEA/DSM/IRFU, France
  • H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
    KEK, Ibaraki, Japan
  • K. Ishimi
    MGI, Chiba, Japan
  • C. Madec, L. Maurice
    CEA/IRFU, Gif-sur-Yvette, France
  
  Marui Galvanizing Co. Ltd. has been studying Vertical Electro-Polishing (VEP) on Nb superconducting accelerator cavity with the goal of mass-production and cost-reduction of Electro-Polishing (EP) process in collaboration with KEK and CEA Saclay. And we invented variable-geometry wings cathode for VEP process to get uniform distributions of both electric current and EP solution flow. Using this cathode, we performed various tests of VEP with Nb single-cell cavities. In this article, we will report the results of vertical test of Nb single-cell cavity which is VEP’ed by cathode with variable-geometry wings.  
 
TUPP110 Quasi Nonlinear Plasma Wakefield Acceleration Experiments plasma, electron, focusing, emittance 680
 
  • S.K. Barber, G. Andonian, B.D. O'Shea, J.B. Rosenzweig, Y. Sakai, O. Williams
    UCLA, Los Angeles, USA
  • M. Ferrario
    INFN/LNF, Frascati (Roma), Italy
  • P. Muggli
    MPI, Muenchen, Germany
  
  It is generally agreed that the best way forward for beam driven plasma wakefield acceleration (PWFA) is in the nonlinear or blowout regime. In this regime the expulsion of the plasma electrons from the beam occupied region produces a linear transverse focusing effect and position independent longitudinal accelerating fields, which can, in principle, produce high quality beams accelerated over many meters. However, certain aspects of a linear plasma response can be advantageous, such as the possibility for resonant excitation of wakefields through the use of pulse trains. Exploiting advantages of both linear and nonlinear PWFA may be achievable through the use of low emittance and tightly focused beams with relatively small charge. In this case the beam density can be greater than that of the ambient plasma while simultaneously having a smaller total charge than the plasma electrons contained in a cubic plasma skin depth allowing for blowout in the region of the beam while simultaneously maintaining a quasi linear response in the bulk plasma. Recent experiments at BNL have been aimed at probing various salient aspects of this regime and are presented here.  
 
TUPP135 Beam Dynamics Calculations and Magnet Design for Future Measurements of Transverse Beam Break-Up at the S-DALINAC* electron, linac, recirculation, sextupole 729
 
  • F. Hug, M. Arnold, L.E. Jürgensen, T. Kürzeder, N. Pietralla, M. Schilling
    TU Darmstadt, Darmstadt, Germany
  
  Funding: *Work supported by the BMBF through 05K13RDA
The superconducting electron accelerator S-DALINAC at TU Darmstadt produces c.w. electron beams of up to 90 MeV. The S-DALINAC consists of a SC 14-MeV injector linac, a SC main linac and two recirculation paths. Currently a third recirculation is in its final design phase and will be constructed end 2014 in order to achieve an energy of 130 MeV in future. The main linac houses eight 20-cell SRF cavities operated at 3 GHz and 2 K. Due to the occurance of transverse beam break-up, the highest stable beam current obtained so far amounts to 5 μA only, which is below the design beam current of 20 μA but sufficient for the nuclear physics experiments carried out at Darmstadt since 1991. In this work we will present beam-dynamics calculations and newly designed magnets for planned experiments at the S-DALINAC in order to benchmark different strategies of increasing the threshold current for beam break-up. 		 
 
TUPP140 Observation of >GV/m Decelerating Fields in Dielectric Lined Waveguides wakefield, radiation, vacuum, electron 743
 
  • B.D. O'Shea, G. Andonian, K.L. Fitzmorris, S. Hakimi, J. Harrison, J.B. Rosenzweig, O. Williams
    UCLA, Los Angeles, California, USA
  • M.J. Hogan, V. Yakimenko
    SLAC, Menlo Park, California, USA
  
  Recent experimental measurements of the energy lost to wakefields in a dielectric lined waveguide are presented. These measurements demonstrate average decelerating gradients on the order of >1 GV/m, for two different structures. The measurements were made at the Facility for Advanced aCcelerator Experimental Tests (FACET) at SLAC National Laboratory using sub-millimeter diameter fifteen-centimeter long quartz fibers of annular cross section. The unique extremely short, high charge, ultra relativistic beam at FACET (200 fs, 3 nC, 20 GeV) allows the use of dielectric wakefield structures of unprecedented size and length. In addition to experimental results, we support conclusions with simulation and theoretical work. This measurement builds on a large body of work previously performed using dielectric wakefield structures in an effort to provide high gradient accelerating structures for tomorrows linear colliders.  
 
THPP017 Beam-Based HOM Studies of the Cornell Energy Recovery Linac 7-Cell SRF Cavity HOM, cavity, linac, cryomodule 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 cavity, niobium, coupling, SRF 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. 		 
 
THPP055 High Power Density Test of PXIE MEBT Absorber Prototype simulation, radiation, electron, focusing 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. 		 
 
THPP058 A Review of Emittance Exchanger Beamlines: Past Experiments and Future Proposals cavity, emittance, electron, laser 982
 
  • 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 laser, electron, linac, controls 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.  
 
THPP092 Development of Slow Neutron Accelerator for Rebunching Pulsed Neutrons neutron, resonance, acceleration, impedance 1062
 
  • 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.  
 
THPP096 RF Coaxial Resonator for Investigating Multipactor Discharges on Metal and Dielectric Surfaces multipactoring, electron, vacuum, coupling 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.  
 
THPP098 Vertical Electropolishing of Nb Coupon Cavity and Surface Study of the Coupon Samples cathode, cavity, target, superconducting-RF 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.  
 
THPP107 Study on Polishing Method of Nb Surface by Periodic Reverse Current Electrolysis With Alkali Solution cavity, SRF, laser, operation 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.  
 
THPP115 PKU 2.45 GHz Microwave Driven H− Ion Source Performance Study electron, ion, ion-source, operation 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]  
 
THPP127 The Status of the Construction of MICE Step IV solenoid, emittance, coupling, cavity 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 		 
 
THPP132 Warming Rate Reduction of the SARAF RF Couplers by Application of a High Voltage Dc Bias operation, proton, cavity, linac 1168
 
  • 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.  
 
THPP138 Measurements of Beam Current and Energy-Dispersion for Ion Beam with Multi-Components ion, ion-source, vacuum, simulation 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]  
 
FRIOA06 AWAKE: Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN plasma, proton, electron, laser 1196
 
  • E. Gschwendtner
    CERN, Geneva, Switzerland
  
  Plasma wakefield acceleration is a promising alternative reaching accelerating fields a magnitude of up to 3 higher (GV/m) when compared to conventional RF acceleration. AWAKE, world’s first proton-driven plasma wakefield experiment, was launched at CERN to verify this concept. In this experiment proton bunches at 400 GeV/c will be extracted from the CERN SPS and sent to the plasma cell, where the proton beam drives the plasma wakefields and creates a large accelerating field. This large gradient of ~GV/m can be achieved by relying on the self-modulation instability (SMI) of the proton beam; when seeded by ionization through a short laser pulse, a train of micro-bunches with a period on the order of the plasma wavelength (~mm) develops, which can drive such a large amplitude wake from a long proton bunch (~12 cm). An electron beam will be injected into the plasma to probe the accelerating wakefield. The AWAKE experiment is being installed at CERN in the former CNGS facility, which must be modified to match the AWAKE requirements. First proton beam to the plasma cell is expected by end 2016.  
slides icon Slides FRIOA06 [7.276 MB]  
 
FRIOB03 Prospects for Accelerator-Driven Thorium Systems neutron, proton, cyclotron, target 1213
 
  • J.-P. Revol
    iThEC, Geneva, Switzerland
  
  To meet the tremendous world energy needs, systematic R&D has to be pursued to replace fossil fuels. Nuclear energy, which produces no green house gases and no air pollution, should be a leading candidate. How nuclear energy, based on thorium rather than uranium, could be an acceptable solution is discussed. Thorium can be used both to produce energy or to destroy nuclear waste. The thorium conference, organized by iThEC at CERN in October 2013, has shown that thorium is seriously considered by developing countries as a key element of their energy strategy. However, developed countries do not seem to move in that direction, while global cooperation is highly desirable in this domain. As thorium is not fissile, an elegant option is to use a proton accelerator to drive an “Accelerator Driven System (ADS)”, as suggested by Nobel Prize laureate Carlo Rubbia. Therefore, the accelerator community has an important challenge to meet: provide the required proton beam for ADS.  
slides icon Slides FRIOB03 [20.039 MB]