Keyword: vacuum
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MOOCA01 High Power Test Results of the SPARC C-Band Accelerating Structures controls, accelerating-gradient, klystron, operation 39
 
  • D. Alesini, M. Bellaveglia, M.E. Biagini, R. Boni, P. Chimenti, R. Clementi, G. Di Pirro, R. D. Di Raddo, M. Ferrario, A. Gallo, V.L. Lollo
    INFN/LNF, Frascati (Roma), Italy
  • M. Brönnimann, R. Kalt, T. Schilcher
    PSI, Villigen PSI, Switzerland
  • L. Ficcadenti
    INFN-Roma, Roma, Italy
  • L. Palumbo
    URLS, Rome, Italy
  
  The energy upgrade of the SPARC photo-injector at LNF-INFN (Italy) from 150 to more than 240 MeV will be done by replacing a low gradient S-Band accelerating structure with two C-band structures. The structures are Traveling Wave (TW) and Constant Impedance (CI), have symmetric axial input couplers and have been optimized to work with a SLED RF input pulse. In the paper we present the results of the low and high power RF tests on the two final fabricated structures that shown the feasibility of the operation at accelerating gradients larger than 35 MV/m.  
slides icon Slides MOOCA01 [6.242 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCA01  
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MOOCA02 RF Design and Operation of a Modular Cavity for Muon Ionization Cooling R&D cavity, instrumentation, solenoid, operation 42
 
  • Y. Torun
    IIT, Chicago, Illinois, USA
  • D.L. Bowring, M.A. Palmer, K. Yonehara
    Fermilab, Batavia, Illinois, USA
  
  Funding: Supported by the US Department of Energy Office of Science through the Muon Accelerator Program.
Ionization cooling channel designs call for the operation of high-gradient, normal-conducting RF cavities in multi-Tesla solenoidal magnetic fields. However, strong magnetic fields have been shown in some cases to limit the maximum achievable gradient in RF cavities. This gradient limit is characterized by RF breakdown and damage to the cavity surface. To study this issue, we have developed an experimental program at Fermilab's MuCool Test Area (MTA) based on a modular pillbox cavity operating at 805 MHz. The modular cavity design allows for the evaluation of different cavity geometries and materials – such as beryllium – which may ameliorate or circumvent RF breakdown triggers. We present a summary of recent results and plans for the future of the MTA normal conducting RF cavity program. 		 
slides icon Slides MOOCA02 [32.552 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOOCA02  
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MOPRO018 Booster of Electrons and Positrons (BEP) Upgrade to 1 GeV dipole, injection, positron, booster 102
 
  • D.B. Shwartz, D.E. Berkaev, D.V. Bochek, I. Koop, I.E. Korenev, A.A. Krasnov, I.K. Sedlyarov, P.Yu. Shatunov, Y.M. Shatunov, I.M. Zemlyansky
    BINP SB RAS, Novosibirsk, Russia
  
  At present new electron and positron injection complex in BINP is comissioned and ready to feed VEPP-2000 collider with intensive beams with energy of 450 MeV. To obtain peak luminosity limited only by beam-beam effects in whole energy range of 160-1000 MeV and to perform high average luminosity with small dead time the top-up injection is needed. Booster BEP upgrade to 1 GeV includes modification of all magnetic elements, including warm dipoles magnetic field increase up to 2.6 T, vacuum chamber, RF-system, injection-extraction system. BEP comissioning is scheduled to the end of 2014.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO018  
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MOPRO030 Changes to the LHC Beam Dumping System for LHC Run 2 dumping, operation, kicker, controls 134
 
  • J.A. Uythoven, M.G. Atanasov, J. Borburgh, E. Carlier, S. Gabourin, B. Goddard, N. Magnin, V. Senaj, N. Voumard, W.J.M. Weterings
    CERN, Geneva, Switzerland
  
  The LHC beam dumping system performed according to expectations during Run 1 of the LHC (2009 – 2013). A brief overview of the experience is given, including a summary of the observed performance in comparison to expectations. An important number of changes are applied to the beam dumping system during the present Long Shutdown on order to further improve its system safety and performance. They include the addition of a direct link between the Beam Interlock System and the re-triggering system of the dump kickers, the modification of the uninterrupted electrical power distribution architecture, the upgrade of the HV generators, the consolidation of the trigger synchronization system, the modifications to the triggering system of the power switches and the changes to the dump absorbers TCDQ.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO030  
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MOPRO036 Beam Life Time and Stability Studies for ELENA electron, antiproton, emittance, simulation 154
 
  • J. Resta-López, O. Karamyshev, D. Newton, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • O. Karamyshev, D. Newton, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • J. Resta-López
    IFIC, Valencia, Spain
  
  Funding: Work supported by the EU under Grant Agreement 624854 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1.
The Extremely Low ENergy Antiproton ring (ELENA) is a small synchrotron equipped with an electron cooler, which shall be constructed at CERN to decelerate antiprotons to energies as low as 100 keV. At such low energies it is very important to carefully take contributions from electron cooling and heating effects (e.g. on the residual gas) into account. Detailed investigations into the ion kinetics under consideration of effects from electron cooling and scattering on the residual gas have been carried out using the BETACOOL code. In this contribution a consistent explanation of the different physical effects acting on the beam in ELENA is given. Beam lifetime, equilibrium momentum spread and emittance are all estimated based on numerical simulations. Finally, optimum machine settings are presented as a result of optimization studies. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO036  
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MOPRO044 Construction and Bench Testing of a Prototype Rotatable Collimator for the LHC impedance, collimation, controls, operation 178
 
  • T.W. Markiewicz, E.L. Bong, L. Keller
    SLAC, Menlo Park, California, USA
  • O. Aberle, A. Bertarelli, P. Gradassi, A. Marsili, S. Redaelli, A. Rossi, B. Salvachua, G. Valentino
    CERN, Geneva, Switzerland
  
  Funding: This work partially supported by the U.S. Department of Energy through the US LHC Accelerator Research Program (LARP) and contract DE-AC02-76SF00515.
A second generation prototype rotatable collimator has been fabricated at SLAC and delivered to CERN for further vacuum, metrology, function and impedance tests. The design features two cylindrical Glidcop jaws designed to each absorb 12kW of beam in steady state and up to 60kW in transitory beam loss with no damage and minimal thermal distortion. The design is motivated by the use of a radiation resistant high Z low impedance readily available material. A vacuum rotation mechanism using the standard LHC collimation jaw positioning motor system allows each jaw to be rotated to present a new 2cm high surface to the beam if the jaw surface were to be damaged by multiple full intensity beam bunch impacts in a asynchronous beam abort. Design modifications to improve on the first generation prototype, pre-delivery functional tests performed at SLAC and post-delivery test results at CERN are presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO044  
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MOPRO051 SOLEIL Operation and On-going Projects operation, injection, storage-ring, photon 200
 
  • L.S. Nadolski, C. Benabderrahmane, P. Betinelli-Deck, F. Bouvet, P. Brunelle, A. Buteau, L. Cassinari, M.-E. Couprie, X. Delétoille, C. Herbeaux, N. Hubert, M. Labat, J.-F. Lamarre, P. Lebasque, A. Lestrade, A. Loulergue, P. Marchand, O. Marcouillé, J.L. Marlats, A. Nadji, R. Nagaoka, P. Prigent, J.P. Ricaud, M.-A. Tordeux
    SOLEIL, Gif-sur-Yvette, France
  
  The 2.75 GeV synchrotron light source SOLEIL delivers photons to 27 beamlines; 2 new ones are under construction together with the FEMTOSLICING project of which commissioning started in January 2014. Five filling patterns are available for the users in Top-up injection mode. The storage ring is running with an upgraded optics less sensitive to insertion device (ID) configurations and giving both better beam lifetime and injection efficiency. The beam position stability remains excellent with a focus on electron vertical beam-size stability for the new very long beamlines. A gating system during Top-up injection improves significantly the quality of the spectrum on an infrared beamline. Several heavy actions of maintenance and upgrades on crucial subsystem equipment are underway. Others accelerator projects are going on such as the design and construction of new IDs, new Multipole Injection Kicker, radiation damage studies as well as R&D on solid-state amplifiers.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO051  
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MOPRO055 ESRF Upgrade Phase II Status lattice, storage-ring, emittance, sextupole 209
 
  • J.-L. Revol, P. Berkvens, J.C. Biasci, J-F. B. Bouteille, N. Carmignani, J. Chavanne, F. Ewald, L. Farvacque, L. Goirand, M. Hahn, L. Hardy, J. Jacob, J.M. Koch, G. Le Bec, S.M. Liuzzo, T. Marchial, D. Martin, B. Nash, T.P. Perron, E. Plouviez, P. Raimondi, K.B. Scheidt, V. Serrière, R. Versteegen
    ESRF, Grenoble, France
  
  The ESRF is close to the end of the first phase (2009-2015) of its Upgrade Programme and has defined the objectives for the ensuing second phase. It envisions a major upgrade of the source to best serve the new science opportunities. The ESRF Council endorsed the proposal to perform the technical design study of a new 7-bend achromat lattice. This configuration will allow the storage ring to operate with a decrease in horizontal emittance by a factor of about 30 and a consequent increase in brilliance and coherence of the photon beam. This paper reports on the status of the accelerator project, highlighting the progress in the technical design.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO055  
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MOPRO059 Fluka Calculations of Gamma Spectra at BESSY injection, radiation, operation, synchrotron 219
 
  • K. Ott, Y. Bergmann
    HZB, Berlin, Germany
  
  Funding: Funded by the Bundesministerium für Bildung und Forschung and by the Land Berlin
Since 22nd October 2012 BESSY is operated in top-up mode. Losses of electrons during injection cause an electromagnetic cascade, that consists of high energetic photons of the bremsstrahlung, and secondary electrons and positrons from the pair creations. The bremsstrahlung spectrum has a maximum at 1.022 MeV owing to pair creations. The spectrum has a high energetic tail, that reaches up to the electron energy of 1.7 GeV at BESSY. The low energy part of the electromagnetic cascade is produced by compton scattering or the photo - effect. Due to the opened beamshutters during top-up injections, the low energetic part of the bremsstrahlung spectrum can reach the experimental hall. We used the particle interaction and transport code FLUKA for the calculations of both the fluence and the dose distribution. We calculated the gamma spectra of the radiation through the shielding walls and through the front-ends. We discuss the question whether additional safety measures are necessary for top-up operation due to the low energy part of the spectrum. From our calculations we determined the correction factors for our ionisation chambers of the ambient dose measurement system. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO059  
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MOPRO061 Study of the Beam Lifetime at the Synchrotron Light Source DELTA scattering, electron, synchrotron, simulation 222
 
  • M.A. Jebramcik, H. Huck, S. Khan, R. Molo
    DELTA, Dortmund, Germany
  
  DELTA is a 1.5-GeV synchrotron light source operated by the TU Dortmund University. The beam lifetime, which is a critical issue for user operation of a light source, was studied experimentally and by simulation for different operation modes, i.e. single-bunch and multibunch fill patterns and for different beam currents. The electron loss rate is dominated by residual-gas scattering (Coulomb scattering and Bremsstrahlung) and by electron-electron scattering (Touschek effect). Since these processes depend in different ways on the momentum acceptance of the storage ring, a variation of the RF cavity voltage allows to disentangle their respective contributions to the total loss rate. The experimental results lead to a consistent picture for different operation modes with a characteristic dependence of the residual-gas pressure on the beam current.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO061  
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MOPRO071 Wake Field and Impedance Calculation due to the Beam Position Monitor in the ILSF Storage Ring impedance, wakefield, storage-ring, factory 246
 
  • H. Ghasem
    IPM, Tehran, Iran
  • M. Razazian
    ILSF, Tehran, Iran
  
  The Beam Position Monitors (BPMs) are usually used in the particles accelerators to observe position of the beam and to record longitudinal bunch shape. As the vertical beam size demands beam stabilities on the submicron level in the particle accelerators, there must be a sever precision on designing and fabrication of the BPMs. In this paper, we have explored effect of the BPMs on the total impedance and loss factor of the ILSF storage ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO071  
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MOPRO073 Design of Iranian Light Source Facility RF Shielded Bellows impedance, storage-ring, wakefield, electron 252
 
  • H. Ghasem
    IPM, Tehran, Iran
  • J. Etemad Moghadam
    ILSF, Tehran, Iran
  
  Total impedance is one of the most effective parameters for proper operation of an accelerator system. This quantity is evaluated with the summation of individual component impedance of the vacuum pipe and is desired to be as low as possible. The bellows have very significant effects on total impedance of the accelerator systems particularly synchrotron light source storage rings. Design of the bellow for Iranian Light Source Facility (ILSF) with a practical approach for fabrication has been down. Minimization of the total impedance budget, loss factor and the resulting wake field due to the passage of 400 mA electron beam is the main goal of our design.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO073  
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MOPRO084 Recent Development and Operational Status of PF-Ring and PF-AR undulator, injection, photon, operation 286
 
  • T. Honda, M. Adachi, S. Asaoka, K. Haga, K. Harada, Y. Honda, M. Izawa, T. Kageyama, Y. Kamiya, Y. Kobayashi, K. Marutsuka, T. Miyajima, H. Miyauchi, S. Nagahashi, N. Nakamura, T. Nogami, T. Obina, M. Ono, T. Ozaki, H. Sagehashi, H. Sakai, S. Sakanaka, H. Sasaki, Y. Sato, M. Shimada, K. Shinoe, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, R. Takai, H. Takaki, Y. Tanimoto, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, Ma. Yoshida, S.I. Yoshimoto
    KEK, Ibaraki, Japan
  
  Update of the first-generation undulators installed in 1980s is pushed forward at PF-Ring, a 2.5-GeV SR source of KEK, taking advantage of the expanded straight sections reconstructed in 2005. New undulators have been designed as elliptically polarizing undulators each has 6 magnetic arrays to obtain various polarization states, not only circular polarization but also linear (horizontal and vertical) polarization. Three undulators will be installed in FY2013 and FY2014 for BL02, BL13 and BL28. For BL02, the longest straight section of about 9 m, the new undulator will be installed in tandem with the existing planar undulator, in order to cover the wide photon energy range from 15 eV to 2 keV. At PF-AR, a 6.5-GeV SR source, a new direct beam transport (BT) line from the injector LINAC is under construction. Super KEKB which shares the injector LINAC with PF-Ring and PF-AR will be commissioned at the end of FY2014. The full-energy continuous injection of PF-AR will be available as a simultaneous injection with the 7-GeV HER, the 4-GeV LER and PF-Ring not so later than the commissioning of Super KEKB.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO084  
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MOPRO100 Engineering Integration Constraints on the Beam Physics Optimisation of the DDBA Lattice for Diamond lattice, sextupole, dipole, quadrupole 322
 
  • R. Bartolini, M. Apollonio, C.P. Bailey, M.P. Cox, N.P. Hammond, R. Holdsworth, J. Kay, I.P.S. Martin, V.V. Smaluk, R.P. Walker
    DLS, Oxfordshire, United Kingdom
  • T. Pulampong
    JAI, Oxford, United Kingdom
  
  The design and optimisation of the new DDBA lattice for Diamond has been performed taking fully into account, from the early stages, the geometry and the engineering integration constraints. In this paper we review the evolution of the DDBA cell, the rationale for its modification and the optimisation strategy used.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO100  
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MOPRO102 Engineering Solutions for the Diamond Double Double Bend Achromat Project dipole, lattice, synchrotron, multipole 328
 
  • J. Kay, M.P. Cox, A.G. Day, N.P. Hammond, R. Holdsworth, H.C. Huang, P.J. Vivian
    DLS, Oxfordshire, United Kingdom
  
  The project to install a Double Double Bend Achromat (DDBA) providing an additional Insertion Device (ID) source for a new beamline at the Diamond Light Source is proceeding. This DDBA cell employs many of the technologies required for Diffraction Limited Storage Rings (DLSRs) and this paper describes the vacuum vessel, magnet and girder solutions in manufacture for the DDBA.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO102  
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MOPRO103 The Double-double Bend Achromat (DDBA) Lattice Modification for the Diamond Storage Ring dipole, lattice, quadrupole, sextupole 331
 
  • R.P. Walker, M. Apollonio, C.P. Bailey, R. Bartolini, M.P. Cox, R.T. Fielder, N.P. Hammond, M.T. Heron, J. Kay, I.P.S. Martin, S.P. Mhaskar, G. Rehm, E.C.M. Rial, B. Singh, V.V. Smaluk, A. Thomson
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini, T. Pulampong
    JAI, Oxford, United Kingdom
  
  The concept of converting individual cells of the Diamond Double Bend Achromat (DBA) lattice into a modified 4-bend achromat with a new straight section for insertion devices (IDs) in the middle of the arc, grew out of earlier studies of low emittance MBA lattices*, and was motivated by the need for additional ID straight sections, since all of the 22 ID straight sections in the Diamond storage ring are either occupied or have been allocated to future beamlines. Such a modification effectively replaces each DBA cell with two new DBA cells, hence the term Double-DBA or DDBA has come to be used for the project. Since the tangent point for bending magnet beamlines lies close to the start of the second dipole in the original DBA, this allows unused exit ports and spaces on the experimental hall which are available for future bending magnet beamlines to be used for higher performance ID beamlines. In this report we present an overview of the status of the project, the various accelerator physics and engineering studies that have been carried out, and plans for the implementation of one or two DDBA cells in Diamond.
* R. Bartolini, IPAC'13, p. 237 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO103  
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MOPME007 Multi-objective Optimization of the Linear and Non-linear Beam Dynamics of Synchrotron SOLEIL storage-ring, multipole, lattice, betatron 388
 
  • X.N. Gavaldà, A. Díaz Ortiz, L.S. Nadolski
    SOLEIL, Gif-sur-Yvette, France
  
  One of the most important challenges for the actual and new third generation of synchrotron light sources is to optimize the linear and the non-linear beam dynamics of these strong focusing lattices. The optimization of a storage ring lattice is a multi-objective problem that involves a high number of constraints in a multi-dimensional parameter space. In this paper we used Multi-Objective Genetic Algorithm (MOGA) and the tracking code ELEGANT to optimize the linear and non-linear beam dynamics of the SOLEIL synchrotron light source. The objectives of our optimization are the dynamical aperture and the momentum aperture which are strongly correlated to the injection efficiency and the Touschek lifetime, respectively. This paper will discuss the deployment of this computational approach using the SOLEIL computer cluster. The first results will also be presented and we will discuss possible improvements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME007  
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MOPME044 Upgrade of the Machine Interlock System for the ELBE Accelerator Facility PLC, electron, controls, status 469
 
  • M. Justus, M. Freitag, B. Lange, P. Michel, W. Sorge, R. Steinbrück, H. Tietze
    HZDR, Dresden, Germany
  
  The ELBE facility with its 40 MeV C.W. LINAC has recently received an upgrade in terms of new secondary radiation sources and beam lines, while advancing the accelerator infrastructure towards 1.6 mA C.W. operation (1.0 mA before). Therefore, the machine interlock system (MIS) was redesigned in parts to meet the new timing requirements resulting from the increased overall beam power. It comprises fast beam loss detection and a PLC based beam line equipment protection system (EPS), both tripping the key components of the electron sources. The former tripping system using PLC interrupts was replaced by an in-house developed staggered CPLD based system with optical transmission and a PROFINET IO interface for control system integration. The EPS is distributed on several PLCs and has been improved in terms of M2M communication. Further, the vacuum inrush protection was completely renewed using brought-in equipment. This contribution depicts the technical features and performance of the MIS subsystems, as well as the actual status within the upgrade project.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME044  
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MOPME074 High Voltage Performance of the Beam Screen of the LHC Injection Kicker Magnets injection, kicker, operation, impedance 541
 
  • M.J. Barnes, P. Adraktas, G. Bregliozzi, S. Calatroni, P. Costa Pinto, H.A. Day, L. Ducimetière, V. Gomes Namora, T. Kramer, V. Mertens, M. Taborelli
    CERN, Geneva, Switzerland
  
  The LHC injection kicker magnets include beam screens to shield the ferrite yokes against wakefields resulting from the high intensity beam. The screening is provided by conductors lodged in the inner wall of a ceramic support tube. The design of the beam screen has been upgraded to overcome limitations and permit LHC operation with increasingly higher bunch intensity and short bunch lengths: the new design also significantly reduces the electric field associated with the screen conductors, decreasing the probability of electrical breakdown. The high voltage conditioning process for the upgraded kicker magnets is presented and discussed. In addition a test setup has been utilized to study flashover, on the inner wall of the ceramic tube, as a function of both applied voltage and vacuum pressure: results from the test setup are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME074  
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MOPME075 Cooling of the LHC Injection Kicker Magnet Ferrite Yoke: Measurements and Future Proposals kicker, injection, simulation, operation 544
 
  • M.J. Barnes, S. Bouleghlimat, L. Ducimetière, M. Garlaschè, V. Gomes Namora, T. Kramer, R. Noulibos, Y. Sillanoli, Z.K. Sobiech, W.J.M. Weterings
    CERN, Geneva, Switzerland
  
  LHC operation with high intensity beam, stable for many hours, resulted in significant heating of the ferrite yoke of the LHC Injection Kicker Magnets. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the yoke can require several hours to cool sufficiently to allow re-injection of beam, thus limiting the running efficiency of the LHC. The beam screen, which screens the ferrite yoke from wakefields, has been upgraded to limit ferrite heating. In addition it is important to improve the cooling of the ferrite yoke: one method is to increase the internal emissivity of the cylindrical vacuum tank, in which the kicker magnet is installed. This paper describes a method developed for measuring the emissivity of the inside of the tanks, which has been benchmarked against measurements of the ferrite yoke temperature during heat treatment in an oven and transient thermal simulations. Conclusions are drawn regarding an ion bombardment technique evaluated for improving emissivity without degrading vacuum properties. In addition initial concepts for improved cooling are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME075  
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MOPME078 Relief of an Electric Field via a Cone Structure high-voltage, kicker, extraction, booster 550
 
  • Y.T. Huang, C.K. Chan, C.S. Chen, J.-R. Chen, G.-Y. Hsiung, Y.-H. Liu
    NSRRC, Hsinchu, Taiwan
  • J.-R. Chen
    National Tsing Hua University, Hsinchu, Taiwan
  
  A terminated power cable is typically applied not only for terminated ends but also to connect two or more cables. The electric field inside the insulation layer becomes disturbed when a coaxial cable structure is broken and the electric stress increases near the ground edge. A structure of cone type is a major method to alter the lines of equi- potential and to relieve the electric stress around the ground. The dimensions of the cone depend on the cable structure. In this paper we introduce a way to calculate the displacement of equi-potential lines when a cone is brought into a coaxial cable, RG220, and then determine a suitable angle and length of the cone, which are important factors to withstand tens of kV and even greater. The corresponding high-voltage tests are also presented here.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME078  
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MOPME079 The DC and AC Withstands Test for TPS Booster Injection Kicker booster, kicker, injection, extraction 554
 
  • Y.-H. Liu, C.K. Chan, C.-S. Chen, H.H. Chen, J.-R. Chen, Y.T. Huang, C.S. Yang
    NSRRC, Hsinchu, Taiwan
  
  TPS requires highly precise and stable pulsed magnets for top-up mode operation. One injection and two extraction in vacuum kicker magnets in the booster ring are designed and noticed to minimize driving voltage. The HV insulation for magnet itself and vacuum feedthrough need to be tested. A DC withstand voltage tester MUSASHI 3802 (Model: IP-701G) is used to test the DC breakdown voltage, which the maximum driving voltage is 37 kV. And the AC withstand voltage tester was also test the AC breakdown voltage. Thicker than 10 mm ceramic plate could effectively avoid the breakdown occurred with 37 kV DC charging. Thus HV withstand voltage will be higher in vacuum chamber and the insulation with HV will not be the problem.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME079  
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MOPRI015 Installing the VESPA H− Ion Source Test Stand at RAL ion, ion-source, extraction, plasma 614
 
  • S.R. Lawrie, D.C. Faircloth, A.P. Letchford, M. Perkins, M. Whitehead, T. Wood
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  A Penning-type negative hydrogen (H—) ion source has been used reliably on the ISIS pulsed spallation neutron and muon facility at the Rutherford Appleton Laboratory (RAL) in the UK for almost 30 years. However a detailed study of the ion source plasma and extraction has never been undertaken. If these properties were known, the beam emittance and losses due to collimation could be reduced, and the lifetime increased. This paper summarises the progress made on installing a Vessel for Extraction and Source Plasma Analyses (VESPA) to fill the knowledge gap.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI015  
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MOPRI019 In-situ Characterization of K2CsSb Photocathodes cathode, electron, laser, ion 627
 
  • M. Schmeißer, A. Jankowiak, T. Kamps, S.G. Schubert
    HZB, Berlin, Germany
  • S.G. Schubert
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by German Bundesministerium für Bildung und Forschung contract 05K12CB2 PCHB and Land Berlin.
Alkali antimonide photocathodes with high quantum efficiency hold the promise of delivering electrons for high-brightness injectors. A drift type spectrometer (momentatron) was attached to the HZB preparation system to allow in-situ characterization within short time after fabrication and possibly identify correlations between growth process and cathode performance parameters. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI019  
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MOPRI024 NEA-GaAs (Cs, O) Photocathodes for the ELBE SRF Gun gun, SRF, cathode, laser 639
 
  • R. Xiang, A. Arnold, P.N. Lu, P. Michel, P. Murcek, J. Teichert, H. Vennekate
    HZDR, Dresden, Germany
  
  Funding: supported by the European Community under the FP7 programme (EuCARD-2, contract number 312453, and LA3NET, contract number 289191), and by the BMBF grant 05K12CR1.
At HZDR a preparation chamber for NEA-GaAs (Cs, O) has been built and commissioned. GaAs is the next photocathode material for the ELBE SRF gun, which has been successfully operated with Cs2Te layer in last years. GaAs At HZDR a preparation chamber for NEA-GaAs (Cs, O) has been built and tested. GaAs is the next photocathode material for the ELBE SRF gun, which has been successfully operated with Cs2Te photocathode in last years. GaAs photocathodes are advantageous because of their high quantum efficiency (QE) with visible light and the extensive experiences of their use in DC guns. Furthermore, GaAs photocathodes provide the possibility to realize a polarized SRF gun in the future. In this presentation we will introduce the new preparation system and the first results of the GaAs tests. The new transfer system under construction will be also presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI024  
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MOPRI025 Recent Improvement of Cs2Te Photocathodes at HZDR cathode, gun, SRF, cavity 642
 
  • R. Xiang, A. Arnold, P.N. Lu, P. Michel, P. Murcek, J. Teichert, H. Vennekate
    HZDR, Dresden, Germany
  
  Funding: Work supported by the European Community-Research Infrastructure Activity (EuCARD, contract number 227579), and the support of the German Federal Ministry of Education and Research grant 05 ES4BR1/8.
The SRF gun has been successfully operated for the radiation source ELBE at HZDR. To achieve higher current and lower beam emittance, a new niobium cavity with superconducting solenoid and a new 13 MHz laser have been recently developed. For this reason, better photocathodes with high quantum efficiency are urgently in demand. In this work we improve the present Cs2Te preparation system for cleaner environment and more precise stoichiometric control than before. A new mask is designed to prevent cesium pollution of the cathode body. Instead of Kapton only alumina ceramics are used for isolation, and the cathode plugs are degassed at higher temperature. New evaporators are installed and tested to obtain an accurate deposition rate. Furthermore, the cathode transfer system is thoroughly cleaned for a better vacuum condition. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI025  
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MOPRI027 Dark Current Studies at Relativistic Electron Gun for Atomic Exploration – REGAE electron, gun, cavity, operation 649
 
  • H. Delsim-Hashemi, K. Flöttmann
    DESY, Hamburg, Germany
  
  Electron diffraction is a tool for exploring structural dynamics of matter. The scattering cross section is orders of magnitude higher for electrons than for X-rays so that only a small number of electrons is required to achieve comparable results. However, the required electron beam quality is extraordinary. To study e. g. proteins a coherence length of 30 nm is required which translates into a transverse emittance of 5 nm at a spot size of 0.4mm. In addition short bunch lengths down to 10 fs and a temporal stability of the same order are required in order to study chemical reactions or phase transitions in pump probe type experiments. These are challenging parameters for an electron source, which demand improvements at many frontiers. Dark current degrades contrast of diffraction patterns in all experiments. Understanding dark-current generation and propagation can lead to better methods to decrease it. In this paper dark current studies that are performed at REGAE will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI027  
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MOPRI030 Basic Design of a 20K C-band 2.6-cell Photocathode RF Gun cavity, gun, simulation, electron 658
 
  • T. Tanaka, M. Inagaki, K. Nakao, K. Nogami, T. Sakai
    LEBRA, Funabashi, Japan
  • M.K. Fukuda, T. Takatomi, J. Urakawa, M. Yoshida
    KEK, Ibaraki, Japan
  • T.S. Shintomi
    Nihon University, Tokyo, Japan
  
  Funding: This research was supported by the Photon and Quantum Basic Research Coordinated Development Program of the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT).
A cryocooled C-band photocathode RF gun operating at 20K is under design at Nihon University. The RF gun is of BNL-type 2.6-cell pillbox cavity with a resonant frequency of 5712 MHz. With high-purity Oxygen-free copper used as the cavity material, the quality factor of the cavity is expected to be approximately 60000 from theoretical prediction of the anomalous skin effect at low temperatures. Considering the cooling capacity, initial operation of the RF gun is assumed at a duty factor of 0.01%. The cavity elements designed for low-power test is in preparation for machining. The low-power test at room temperature is scheduled early spring in 2014 before assembled at KEK by means of diffusion bonding technique. Since it is intended for the basic understanding and measurements of low temperature RF properties, the cavity is not equipped with structures for the photocathode assembling or the RF input coupler. The cavity design and the results of RF properties measured at room temperature before diffusion bonding will be reported. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI030  
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MOPRI031 Multi-alkali Photocathode R&D cathode, laser, electron, experiment 661
 
  • Y. Seimiya, M. Kuriki, N. Yamamoto
    HU/AdSM, Higashi-Hiroshima, Japan
  
  Multi-alkali photocathode has excellent features: high quantum efficiency, long lifetime, and excitation by visible light, for example green laser. The multi-alkali cathode is considered to be one of the best candidate of the high brightness electron source of the advanced electron accelerator such as ERL and FEL. We study conditions of multi-alkali evaporations, such as thicknesses, substrate temperature, and evaporation rate, and examine the cathode performances, such as quantum efficiency and extractable current density. Antimony (Sb), potassium (K), and cesium (Cs) are used in our evaporation system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI031  
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MOPRI032 A STUDY ON ROBUSTNESS OF NEA-GAAS PHOTOCATHODE* cathode, electron, experiment, emittance 664
 
  • K. Uchida, R. Kaku, M. Kuriki, K. Miyoshi, Y. Seimiya, N. Yamamoto
    HU/AdSM, Higashi-Hiroshima, Japan
  • H. Iijima
    Tokyo University of Science, Tokyo, Japan
  
  Electron source is one of the most important component in the advanced linac. There is a strong demand on the high performance cathode, such as small emittance, high brightness, and short pulse generation. NEA-GaAs photo-cathode is a unique technology which is capable for generating highly polarized and extremely low emittance beam. Quantum efficiency (QE) of the cathode is high in near IR region, so it is favor to generate a high current density beam. These advantages are originated to the Negative Electron Affinity (NEA) surface, but it is fragile so the operational lifetime is limited. A study on a robust NEA surface cathode is reported. According to the hetero-junction model, Cs-Te thin film deposited on GaAs forms a robust NEA surface. We performed the Cs-Te evaporation experiment on a clean GaAs cathode and measured QE spectra. We found that some sample showed a high quantum efficiency up to 900nm wavelength which strongly suggested a NEA surface formation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI032  
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MOPRI038 Study on Quantum Efficiency of NEA-GaAs with Various Thermal Treatments; The Increase in Quantum Efficiency by the Low Temperature Treatment. electron, ion, site, experiment 682
 
  • K. Hayase, R. Chiba, H. Iijima, Y. Inagaki, T. Meguro
    Tokyo University of Science, Tokyo, Japan
  
  Negative electron affinity (NEA) surface are formed by deposition of Cs atoms on p-GaAs, and the drastic increase in the electron emission is observed by the Yo-Yo method. It is necessary to remove oxide layers of GaAs surface for the NEA surface formation, therefore the thermal treatment was carried out prior to the NEA activation. We have discussed the quantum efficiency (QE) with different thermal history. GaAs surfaces cleaned with organic solvents were thermally treated with the temperature sequence of 773K, 823K, and 723K. The NEA activation was carried out at every temperature. The QE less than 1% was obtained with 773K of treatment temperature on the initial surface. Then the QE increased at 10% after treatment at higher 823K. Successive increase of the QE to 13% was observed with a reduced temperature treatment at 723K. The GaAs surfaces after the thermal treatment in the high temperature region with the NEA activation are different from the as-cleaned-GaAs surfaces probably in stoichiometry or morphology due to desorption of As and Ga atoms. The role of thermal treatment with NEA activation is the modification of surface properties important for elevating the QE.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI038  
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MOPRI042 Recent Developments at the High-charge PHIN Photoinjector and the CERN Photoemission Laboratory laser, cathode, feedback, operation 695
 
  • C. Heßler, E. Chevallay, S. Döbert, V. Fedosseev, I. Martini, M. Martyanov, A. Perillo Marcone, Sz. Sroka
    CERN, Geneva, Switzerland
  
  The high-charge PHIN photoinjector has originally been developed to study the feasibility of a photoinjector option for the drive beam of the CLIC Test Facility 3 (CTF3) at CERN and is now being used to investigate the feasibility of a drive beam photoinjector for CLIC. In this paper recent R&D efforts to improve the parameters of the existing system towards CLIC requirements will be discussed. This includes studies of a feedback loop for intensity stabilization, the upgrade of the PHIN vacuum system and the planned upgrade of the driving laser system. For photocathode production and R&D a dedicated photoemission laboratory is available at CERN. To increase the production rate of photocathodes and the availability of the photoemission lab for other studies, an upgrade of the photocathode preparation system with a load-lock system is under study and will also be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI042  
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MOPRI056 Design and Fabrication of a VHF - CW High Repetition Rate Electron Gun cavity, cathode, gun, operation 733
 
  • R.P. Wells, B. Ghiorso, F. Sannibale, J.W. Staples
    LBNL, Berkeley, California, USA
  • T.M. Huang
    IHEP, Beijing, People's Republic of China
  
  Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
A high repetition rate, MHz, electron source is a key element in future FEL based light sources. The Advance Photo-injector Experiment (APEX) at Lawrence Berkeley National Laboratory (LBNL) consists of a high repetition rate 186 MHz (VHF-band) CW electron gun, 1 MHz UV laser source and the diagnostic components necessary to quantify the gun’s performance. The gun design is based on well established, conventional RF cavity design, with a couple notable exceptions. The basis for the selection of this technology, novel design features, fabrication techniques and measured cavity performance are presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI056  
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MOPRI057 Photoemission from III-V Semiconductor Cathodes electron, cathode, photon, scattering 736
 
  • S.S. Karkare
    Cornell University, Ithaca, New York, USA
  • I.V. Bazarov, L. Cultrera, W.J. Schaff
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • X.G. Jin
    Institute for Advanced Research, Nagoya, Japan
  • Y. Takeda
    Nagoya University, Nagoya, Japan
  
  Quantum efficiencies (QE) and mean transverse energies (MTE) of GaAs photocathodes grown using various techniques: metal-organic vapor phase epitaxy (MOVPE), molecular beam epitaxy (MBE), and atomic polishing have been compared and found to be identical. GaAs and GaInP based samples grown at Nagoya University were activated and measured in the Cornell ERL photoinjector. These were found to be in agreement with the samples measured at the ERL injector in KEK.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI057  
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MOPRI058 Metal Plasmonic Nanostructures Functionalized by Atomic Layer Deposition of MgO for Photocathode Applications electron, cathode, resonance, emittance 739
 
  • S.V. Baryshev, S.P. Antipov, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • M.R. Savina, A.V. Zinovev
    ANL, Argonne, Illinois, USA
  • E. Thimsen
    University of Minnesota, Minneapolis, USA
  
  Funding: Euclid TechLabs LLC acknowledges support from the DOE SBIR program, grant No. DE-SC0009572.
To create high current, long lasting electron sources capable of providing sub-ps bunches, new photocathode concepts are sought. Most recently, plasmonic nanostructured metal surfaces or flat metal surfaces activated by an ultrathin MgO are under great attention. We report on a photocathode design combining these two approaches. It consists of plasmonic Ag nanoparticles (NPs) functionalized by 3 MgO monolayers (MLs). Ag NPs were synthesized by an aerosol method and MgO was grown by atomic layer deposition (ALD). The NPs geometry was tuned to obtain broadband >50% absorption in the entire blue range as evidenced by UV-vis. spectroscopy. The WF of 3 MgO MLs/Ag NPs multilayer was reduced by 1 eV compared to bare NPs, from 5 to 4 eV, as evidenced by UPS and Kelvin probe. Reduction by 1 eV is maximal for this pair of materials, and agrees well with experimental and theoretical findings. While the effect on WF is indeed significant, a special handling protocol for Ag before depositing MgO is a must. It would preserve a clean Ag surface with a WF of nearly 4 eV to achieve 3 eV upon ALD of MgO. This and other issues are under study to promote photocathode applications. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI058  
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MOPRI059 Fabrication of Alkali Antimonide Photocathode for SRF Gun cathode, laser, gun, SRF 742
 
  • E. Wang, S.A. Belomestnykh, I. Ben-Zvi, D. Kayran, G.T. McIntyre, T. Rao, J. Smedley, D. Weiss, W. Xu
    BNL, Upton, Long Island, New York, USA
  • I. Ben-Zvi, M. Ruiz-Osés
    Stony Brook University, Stony Brook, USA
  • X. Liang
    SBU, Stony Brook, New York, USA
  • H.M. Xie
    PKU, Beijing, People's Republic of China
  
  Funding: * This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE and DOE grant
The first alkali antimonide photocathode was prepared and inserted into the BNL 704 MHz SRF gun. An excimer laser cleaning system was installed in a cathode deposition chamber and the cleaning technique developed previously was used in the first cathode preparation. We also demonstrated that oxidized cathode can be removed by exposing it to the same excimer laser. In this paper, we show the set up of the incorporated laser cleaning system and the QE enhancement of alkali antimony photocathode. The vacuum evolution at transport cart and QE measurement system are also discussed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI059  
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MOPRI063 Alkali Antimonide Photocathodes in a Can cathode, gun, insertion, controls 745
 
  • J. Smedley, K. Attenkofer, T. Rao, S.G. Schubert
    BNL, Upton, Long Island, New York, USA
  • I. Ben-Zvi, X. Liang, E.M. Muller, M. Ruiz-Osés
    Stony Brook University, Stony Brook, USA
  • J. DeFazio
    PHOTONIS USA Pennsylvanis, Inc., Lancaster, Pennsylvania, USA
  • H.A. Padmore, J.J. Wong
    LBNL, Berkeley, California, USA
  • J. Xie
    ANL, Argonne, Illinois, USA
  
  Funding: Work was supported by the US DOE, under Contracts DE-AC02-05CH11231, DE-AC02-98CH10886, KC0407-ALSJNT-I0013, DE-FG02-12ER41837 and DE-SC0005713. Use of CHESS is supported by NSF award DMR-0936384.
The next generation of x-ray light sources will need reliable, high quantum efficiency photocathodes. These cathodes will likely be from the alkali antimonide family, which currently holds the record for highest average current achieved from a photoinjector. In this work, we explore a new option for delivering these cathodes to a machine which requires them: use of sealed commercial vacuum tubes. Several sealed tubes have been introduced into a vacuum system and separated from their housing, exposing the active photocathode on a transport arm suitable for insertion into a photoinjector. The separation has been achieved without loss of QE. These cathodes are compared to those grown via traditional methods, both in terms of QE and in terms of crystalline structure, and found to be similar. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI063  
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MOPRI073 Status of the HESR Electron Cooler Test Set-up electron, gun, diagnostics, solenoid 771
 
  • M.W. Bruker, K. Aulenbacher, J. Dietrich, S. Friederich, T. Weilbach
    HIM, Mainz, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  
  For the High Energy Storage Ring (HESR) at FAIR, it is planned to install an electron cooling device with a beam current of 3 A and a beam energy of 8 MeV. A test set-up was built at Helmholtz-Insitut Mainz (HIM) to conduct a feasibility study. One of the main goals of the test set-up is to evaluate the gun design proposed by TSL (Uppsala) with respect to vacuum handling, electric and magnetic fields, and the resulting beam parameters. Another purpose of the set-up is to reduce recuperation losses to less than 10-5. To measure this quantity and to mitigate collection losses, a Wien filter has been designed and installed. Beam diagnostics will be carried out with a COSY-style beam position monitor. The latest progress of the project is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI073  
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MOPRI078 High Power Cyclotrons for Neutrino Experiments cyclotron, experiment, extraction, proton 788
 
  • D. Winklehner, J.R. Alonso, W.A. Barletta, A. Calanna, J.M. Conrad
    MIT, Cambridge, Massachusetts, USA
  • A. Adelmann
    PSI, Villigen PSI, Switzerland
  • L. Calabretta, D. Campo
    INFN/LNS, Catania, Italy
  • M. Shaevitz
    Columbia University, New York, USA
  • J.J. Yang
    CIAE, Beijing, People's Republic of China
  
  DAEδALUS* and IsoDAR** experiments needs large intense neutrino fluxes to investigate respectively the CP-Violation in the neutrino sector and the existence of sterile neutrino. DAEδALUS requires three neutrino sources driven by proton beams of ~800 MeV at powers of several megawatts placed at distances of 1.5, 8 and 20 km from the detector. Two cyclotrons working in cascade are chosen to deliver these high power beams. The first cyclotron accelerates the H2+ ions beam up to 60 MeV/amu. The beam is then extracted with an electrostatic deflector and reaccelerated up to 800 MeV/amu through a superconducting ring cyclotron. The acceleration of H2+ has two advantages: it reduces the space charge effect along the injection and acceleration inside the first cyclotron and allows the extraction of the beam from the last accelerator using a stripper foil. The injector cyclotron can be used in stand-alone mode to drive the IsoDAR experiment, which needs the accelerator placed near an underground neutrino detector. The design and the results of beam dynamic simulations will be shown. the results of preliminary injection and acceleration tests into a cyclotron test bench will be presented.
* J. Alonso et al., arXiv:1006.0260[physics.ins-det] (2010).
** A. Bungau et al., Phys. Rev. Lett. 109 141802 (2012).
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI078  
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MOPRI084 Beam Dynamic into the Transfer RIB Lines to the DESIR Facility at GANIL-SPIRAL2 quadrupole, ion, emittance, diagnostics 806
 
  • L. Perrot, H. Cherif
    IPN, Orsay, France
  
  Funding: French ANR, Investissements d'Avenir, EQUIPEX Contract number ANR-11-EQPX-0012
The new ISOL facility SPIRAL2 is currently being built at GANIL, Caen France. SPIRAL2 will produce a large number of new radioactive ion beams (RIB) at high intensities. The DESIR facility will receive beams from the upgraded SPIRAL1 facility of GANIL (stable beam and target fragmentation), from the S3 Low Energy Branch (fusion-evaporation and deep-inelastic reactions) and from the SPIRAL2 production cave (n-induced fission of 238U, nucleon transfer and fusion-evaporation reactions). In order to deliver the RIB to the experimental set-ups installed in the DESIR hall, 110 meters of beam line have to be designed, originating from 3 different facilities. This paper will focus on the studies which have been done on these transfer lines: beam optics and errors calculations, quadrupoles, diagnostics and mechanical designs. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI084  
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MOPRI087 Challenges of the Technical Layout of the SIS 100 Extraction System extraction, quadrupole, septum, radiation 815
 
  • N. Pyka, L.H.J. Bozyk, U. Kopf, C. Mühle, D. Ondreka, P. Rottländer, P.J. Spiller, St. Wilfert
    GSI, Darmstadt, Germany
  • A.G. Kalimov
    St. Petersburg State Polytechnic University, St. Petersburg, Russia
  
  The FAIR synchrotron SIS100 which is under construction will provide heavy ion and proton beams of high intensity with fast and slow extraction. All extraction devices, including an internal emergency beam dump system, are installed within one straight section. This way, expected systematic beam loss is kept in a relatively small area of the synchrotron. In this area, it is rather challenging to protect components against high radiation fields, to keep XHV conditions, and to allow for maintenance of highly activated components to assure reliable beam operation. In this contribution, the technical measures to fulfill the requirements for the extraction straight section of SIS100 will be presented. These include remote controlled devices to move apart magnet yokes for the purpose of placing beam pipe heater; dedicated star-shaped vacuum chambers with integrated collimators and NEG-panels to reduce pressure bumps due to lost particles behind the electrostatic septa; a high-power multi-stage vertical extraction septum including a variable horizontal deflection.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI087  
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MOPRI101 Field Simulations and Mechanical Implementation of Electrostatic Elements for the ELENA Transfer Lines quadrupole, ion, proton, experiment 855
 
  • D. Barna
    University of Tokyo, Tokyo, Japan
  • W. Bartmann, J. Borburgh, C. Carli, G. Vanbavinckhove
    CERN, Geneva, Switzerland
  
  The Antiproton Decelerator (AD) complex at CERN will be extended by an extra low energy anti-proton ring (ELENA) further decelerating the anti-protons thus improving their trapping. The kinetic energy of 100 keV at ELENA extraction facilitates the use of electrostatic transfer lines to the experiments. The mechanical implementation of the electrostatic devices are presented with focus on their alignment, bakeout compatibility, ultra-high vacuum compatibility and polarity switching. Field optimisations for an electrostatic crossing device of three beam lines are shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI101  
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MOPRI104 Measurement of Beam Ioniziation Loss in SIS18 ion, simulation, injection, extraction 864
 
  • L.H.J. Bozyk, P.J. Spiller
    GSI, Darmstadt, Germany
  
  In the heavy ion synchrotron SIS18 at GSI an ion catcher system has been installed to provide low desorption surfaces for ionization beam loss to reduce dynamic vacuum effects. Medium charge state heavy ions can change their charge state in collission with residual gas molecules. Those ions are cought by the ion catcher system. The ion catcher blocks are mounted electrically insulated, such that it is possible, to directly measure the electrical current, induced by the incident ions. Changes in vacuum density during the acceleration cycle and also the energy dependent decrease of the cross sections for electron loss and electron capture can be measured by this system. Different ion catcher currents, measured during the operation with U28+, and their interpretation are presented. The measurement of ionization beam loss is a valuable tool to benchmark the dynamic vacuum simulations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI104  
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MOPRI105 Heavy Ion Induced Desorption Measurements on Cryogenic Targets target, ion, cryogenics, diagnostics 867
 
  • Ch. Maurer, D.H.H. Hoffmann
    TU Darmstadt, Darmstadt, Germany
  • L.H.J. Bozyk, H. Kollmus, Ch. Maurer, P.J. Spiller
    GSI, Darmstadt, Germany
  
  Funding: Bundesministerium für Bildung und Forschung FKZ 06DA7031
Heavy-ion impact induced gas desorption is the key process that drives beam intensity limiting dynamic vacuum losses. Minimizing this effect, by providing low desorption yield surfaces, is an important issue for maintaining a stable ultra high vacuum during operation with medium charge state heavy ions. For room temperature targets, investigation shows a scaling of the desorption yield with the beam's near-surface electronic energy loss, i.e. a decrease with increasing energy*,**. An optimized material for a room temperature ion-catcher has been found. But for the planned superconducting heavy-ion synchrotron SIS100 at the FAIR accelerator complex, the ion catcher system has to work in a cryogenic environment. Desorption measurements with the prototype cryocatcher for SIS100 showed an unexpected energy scaling***, which needs to be explained. Understanding this scaling might lead to a better suited choice of material, resulting in a lower desorption yield. An experimental setup for systematic examination of this scaling is presented. The cryogenic beam-induced desorption yield of several materials at different temperatures is examined.
* H. Kollmus et al., AIP Conf. Proc. 773, 207 (2005))
** E. Mahner et al., Phys. Rev. ST Accel. Beams 14, 050102 (2011)
*** L.H.J. Bozyk, H. Kollmus, P.J. Spiller, Proc. of IPAC 2012, p. 3239 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI105  
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TUPRO090 Special Elettra Corrector Magnets dipole, controls, power-supply, sextupole 1247
 
  • E. Karantzoulis, D. Castronovo, S. Krecic, G.L. Loda
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  
  To fully control the beam position source point for the dipole beam lines additional correctors are needed. The space available however is minimal and no alternative solution (e.g. additional coils on quadrupoles or sextupoles) is possible making the design of such a magnet very challenging. The design, installation and performance of those special magnets is presented and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO090  
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TUPRO101 Fast Kicker kicker, impedance, simulation 1280
 
  • V.V. Gambaryan, A.A. Starostenko
    BINP SB RAS, Novosibirsk, Russia
  
  Pulsed deflecting magnet project was worked out in BINP. The kicker design task is: impulsive force value is 1 mT*m, pulse edge is 5 ns, and impulse duration is about 200 ns. The unconventional approach to kicker design was offered. The possibility for set of wires using instead of plates using is considered. This approach allows us to reduce the effective plate surface. In this case we can decrease effects related to induced charges and currents. In the result of modelling optimal construction was developed. It includes 6 wires. The magnet aperture is about 5 cm. Calculated field rise time (about 1.5 ns) satisfies the conditions. Induced current effect reducing idea was confirmed. For configuration with 3 wires pair (with cross section of 2 mm) induced current in one wire is about 10% and in the wall is about 40%. However for design with plates current is about 40% and 20% respectively. Obtained magnet construction allows controlling of high field homogeneity by changing currents magnitudes in wires. In general we demonstrated the method of field optimization. Summary. Optimal kicker design was obtained. Wires using idea was substantiated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO101  
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TUPRO107 Prediction of the Field Distribution in CERN-PS Magnets simulation, resonance, synchrotron, injection 1298
 
  • D. Schoerling
    CERN, Geneva, Switzerland
  
  The CERN Proton Synchrotron (PS) has a circumference of 628 m and operates at an energy of up to 26 GeV. It uses one hundred combined function magnets, with pole shapes designed to create a dipolar and a quadrupolar field component. Each magnet is equipped with a main current circuit and five auxiliary current-circuits, which allows controlling the linear and non-linear magnetic fields. These magnets were installed in the 1950s, and part of the compensating circuits have been added or modified since then, resulting in the fact that detailed measurements of the field distribution in each individual magnet as a function of the six currents are not available. This study is performed to estimate, through deterministic and stochastic calculations, the expected mean value and standard deviation of the field harmonics of the installed magnets as input for beam dynamics simulations. The relevant results can be used to design correction schemes to minimise beam losses in the PS and to enable the acceleration of higher brightness beams required to reach the foreseen Large Hadron Collider (LHC) luminosity targets.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO107  
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TUPRO109 Calculation of Heat Load on Double Mini-beta Y Undulators undulator, radiation, synchrotron, synchrotron-radiation 1304
 
  • J.C. Huang, T.Y. Chung, C.-S. Hwang, Y.T. Yu
    NSRRC, Hsinchu, Taiwan
  
  Two collinear in-vacuum undulators (IU22) are adopted for light source of X-ray coherence beamline in Taiwan photon source. Each undulator is 3 meter and the drift space between two undulator is 3.991m. The synchrotron radiation is propagating in the longitudinal direction and will result in a serious heat load problem for undualtor downstream. The magnet array of undualtor downstream will received the synchrotron radiation of 142W from upstream bending magnet and undualtor. Heat load is a critical challenge for in-vacuum undulator in double mini-beta Y lattice and therefore details analysis in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO109  
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TUPME001 Heat Load, Stress and Reaction Force Studies of a Polarized Positron Production Target for the Future International Linear Collider target, positron, photon, undulator 1331
 
  • F. Staufenbiel, S. Riemann
    DESY Zeuthen, Zeuthen, Germany
  • G.A. Moortgat-Pick, A. Ushakov
    University of Hamburg, Hamburg, Germany
  
  The International Linear Collider requires an intense polarized positron beam with yields of about 1014 positrons per second. A polarized positron beam can be produced with a helical undulator passed by the accelerated electron beam to create a high power polarized photon beam. The photon beam penetrates a thin titanium-alloy rotating target wheel of 1m diameter with 500 to 2000 rpm rotation speed and produces polarized positrons. The system should run for 1-2 years without failure. A break down can occur due to the huge heat load in a short time (<1ms). The target design must keep the resulting thermo-mechanical stress below the yield strength and the fatigue limit of the material. FEM ANSYS simulations are used to evaluate the thermo-mechanical stress as well as the vibrations at the bearings of the rotating system. Results are presented with the goal to optimize the target wheel design parameters for a long lifetime.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME001  
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TUPME013 Thermo-mechanical Tests for the CLIC Two-beam Module Study operation, alignment, linac, experiment 1370
 
  • A. Xydou, G. Riddone, A.L. Vamvakas
    CERN, Geneva, Switzerland
  • E. Daskalaki
    NTUA, Athens, Greece
  
  The luminosity goal of CLIC requires micron level precision with respect to the alignment of the components on its two-meter long modules, composing the two main linacs. The power dissipated inside the module components introduces mechanical deformations affecting their alignment and therefore the resulting machine performance. Several two-beam prototype modules must be assembled to extensively measure their thermo-mechanical behavior under different operation modes. In parallel, the real environmental conditions present in the CLIC tunnel should be studied. The air conditioning and ventilation system providing specified air temperature and flow has been installed in the dedicated laboratory. The power dissipation occurring in the modules is being reproduced by the electrical heaters inserted inside the RF structure mock-ups and the quadrupoles. The efficiency of the cooling systems is being verified and the alignment of module components is monitored. The measurement results will be compared to finite element analysis model and propagated back to engineering design. Finally, simulation of the most possible CLIC machine cycles is accomplished and preliminary results are analysed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME013  
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TUPME024 A hybrid six-dimensional muon cooling channel with gas filled cavities emittance, cavity, lattice, simulation 1401
 
  • D. Stratakis
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Obtaining the desired micron-scale emittances for a Muon Collider requires transporting the muon beam through long sections of a beam channel containing rf cavities, absorbers, and focusing solenoids. Here we discuss possible implementation of high-pressure gas-filled RF cavities in a 6D ionization cooling channel and some technical issues associated with it. The key idea of our scheme is a hybrid approach that uses high-pressure gas to avoid cavity breakdown, along with discrete LiH absorbers to provide the majority of the energy loss. We show that the channel performs as well as the original vacuum rf channel while potentially avoiding degradation in rf gradient associated with the strong magnetic field in the cooling channel. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME024  
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TUPME029 Identification of High-frequency Resonant Impedance in the CERN SPS impedance, simulation, damping, resonance 1416
 
  • E.N. Shaposhnikova, T. Argyropoulos, T. Bohl, J.V. Campelo, F. Caspers, J. F. Esteban Müller, A. Lasheen, B. Salvant, H. Timko
    CERN, Geneva, Switzerland
  
  The spectrum of long bunches injected into the ring with RF switched off has been used in the SPS in the past to probe the longitudinal coupling impedance. After a large campaign of shielding of 800 inter-magnet vacuum ports in 1999 - 2001, the microwave instability threshold was significantly increased and the high-frequency spectrum of the beam became practically flat, apart from a prominent peak at around 1.4 GHz. As corresponding high-frequency impedance could potentially lead to microwave instability of high intensity bunches observed now at high energies in the SPS, a search of the source of this impedance was launched. Using a combination of impedance simulations and measurements, vacuum flanges that are present in a large quantity in the machine have been identified as a main source of impedance at this frequency. Particle simulations based on the SPS impedance model, which includes this previously unknown impedance, are able to reproduce the characteristics of the bunch spectrum and amplitude growth rates and hence, confirm that the impedance of the vacuum flanges is responsible for the observed spectral peak.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME029  
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TUPME054 Influence of a Vacuum Gap on a Bunch Wakefield in a Circular Waveguide Filled up with Dielectric wakefield, cavity, radiation, electromagnetic-fields 1489
 
  • T.Yu. Alekhina, A.V. Tyukhtin, V.V. Vorobev
    Saint-Petersburg State University, Saint-Petersburg, Russia
  
  Analysis of electromagnetic field of a particle bunch intersecting several boundaries in a dielectric waveguide is important for the wakefield acceleration technique and other problems of accelerator physics. In previous works we investigated the case of a single boundary in a waveguide*. Now we study the electromagnetic field of the bunch moving in a dielectric circular waveguide and crossing a vacuum cavity. The main attention is given to the case when wakefield (Cherenkov radiation) is generated in dielectric. The behavior of the total field depending on distance and time is explored numerically. Analytical estimations are made as well. Influence of the vacuum gap on the wakefield is considered for different lengths of the gap. It is clarified conditions when the vacuum gap does not practically influence on the wakefield. It is noted that the quasi monochromatic wave (the Cherenkov transition radiation) generated in the vacuum region can be used for restoration of the field in the area after the gap. This effect can be achieved for some optimal parameters of the problem.
* T.Yu. Alekhina, A.V. Tyukhtin, Phys. Rev. ST-AB, v.15, 091302 (2012);
T.Yu. Alekhina, A.V. Tyukhtin, Phys. Rev. ST-AB, v.16, 081301 (2013). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME054  
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TUPRI021 Impedance Calculation and Simulation of Microwave Instability for the Main Rings of SuperKEKB impedance, simulation, cavity, kicker 1600
 
  • D. Zhou, T. Abe, T. Ishibashi, Y. Morita, K. Ohmi, K. Shibata, Y. Suetsugu, M. Tobiyama
    KEK, Ibaraki, Japan
  
  The SuperKEKB B-factory is now under construction. The designs of the components for the SuperKEKB have mostly been finished. This paper summarises the updated results of longitudinal impedance calculations for various components of the main rings. By summing up all available impedances, a pseudo-Green wake function with bunch length of σz=0.5 mm is constructed as an impedance model for consequent studies of collective effects. The results of these studies are also reported in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI021  
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TUPRI027 Detailed Magnetic Model Simulations of the H− Injection Chicane Magnets for the CERN PS Booster Upgrade, including Eddy Currents, and Influence on Beam Dynamics injection, simulation, emittance, space-charge 1618
 
  • E. Benedetto, B. Balhan, J. Borburgh, C. Carli, V. Forte, M. Martini
    CERN, Geneva, Switzerland
  • V. Forte
    Université Blaise Pascal, Clermont-Ferrand, France
  
  The CERN PS Booster will be upgraded with an H− injection system. The chicane magnets for the injection bump ramp-down in 5 ms and generate eddy currents in the inconel vacuum chamber which perturb the homogeneity of the magnetic field. The multipolar field components are extracted from 3D OPERA simulations and are included in the lattice model. The beta-beating correction is computed all along the ramp and complete tracking simulations including space-charge are performed to evaluate the impact of these perturbations and their correction.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI027  
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TUPRI034 Numerical Modeling for CesrTA Measurements of Electron Cloud Buildup in a Quadrupole Magnet electron, detector, quadrupole, positron 1632
 
  • J.A. Crittenden, M.G. Billing, W. Hartung, C. Shill, J.P. Sikora, K.G. Sonnad
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: Work supported by the U.S. National Science Foundation contracts PHY-0734867, PHY-1002467, and the U.S. Department of Energy contract DE-FC02-08ER41538
We describe a numerical model for measurements of the formation of long-lived electron clouds in a quadrupole magnet in the CESR storage ring. The shielded stripline detector measures the electron flux incident on the vacuum chamber wall directly in front of one of the poles of the magnet. The model includes photo-electron production by synchrotron radiation, electrostatic forces from the bunched positron beam and the cloud, macroparticle tracking in the field of the quadrupole, secondary electron emission from the 9.5-cm-diameter cylindrical stainless steel beam-pipe and an analytic calculation of the transmission function of the holes in the vacuum chamber which allow cloud electrons to reach the stripline collector. These modeling studies provide a quantitative understanding of the trapping mechanism which results in cloud electrons surviving the 2.3-microsecond time interval prior to the return of a train of positron bunches. These studies have been performed in the context of the CESR Test Accelerator program, which aims to quantify and mitigate performance limitations on future low-emittance storage and damping rings. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI034  
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TUPRI036 Fast Ion Instability at CESR-TA feedback, ion, simulation, electron 1638
 
  • A. Chatterjee, K.J. Blaser, M. P. Ehrlichman, D. L. Rubin, J.P. Shanks
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: Work supported by NSF and DOE Contracts No. PHY-0734867, No. PHY-1002467, No. PHYS-1068662, No. DE-FC02-08ER41538, No. DE-SC0006505, and the Japan/U.S. Cooperation Program.
Fast Ion Instability can lead to deterioration of an electron beam (increasing emittance and instability of a train of bunches) in storage rings and linacs. We study this at the Cornell Electron Storage Ring Test Accelerator using a 2.1 GeV low emittance beam. As the source of ions is residual gas, our measurements are conducted at various pressures, including nominal vacuum as well as injected gas (Ar, Kr). We measure turn-by-turn vertical bunch size and position, as well as the multi-bunch power spectrum. A detailed simulation is then used to compare theory with observations. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI036  
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TUPRI037 Some Features of Wave Distribution in the Thin-Wall Waveguide impedance, undulator, shielding, radiation 1641
 
  • M. Ivanyan, L.V. Hovakimyan, A. Sargsyan
    CANDLE SRI, Yerevan, Armenia
  
  In this report we derive rigorous and approximate dispersion relations for the round resistive thin-wall waveguide. The features of the distributions of dispersion curves of the waveguide axisymmetric TM modes are obtained. Cases of splitting and degeneracy of modes under consideration are detected and regularities of their behaviours are established.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI037  
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TUPRI038 The Low Energy Particle Wakefield Radiation From the Open End of Internally Coated Metallic Tube radiation, wakefield, experiment, resonance 1644
 
  • M. Ivanyan, A. Grigoryan, A. Sargsyan, A.V. Tsakanian
    CANDLE SRI, Yerevan, Armenia
  
  The radiation of the non-relativistic electron beam from the open end of the resistive circular waveguide is presented. The angular and spectral characteristics of the radiation are determined. The possibility of producing the focused guasi-monochromatic radiation is discussed. The principal scheme of the experiments for 5 and 20 MeV AREAL RF photogun linac is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI038  
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TUPRI041 Study of Collective Beam Instabilities for Sirius impedance, undulator, operation, feedback 1653
 
  • F.H. de Sá, H.O.C. Duarte, L. Liu, N. Milas, X.R. Resende
    LNLS, Campinas, Brazil
  
  In this paper we present the on going work of construction of the Sirius impedance budget and instability threshold estimates for several machine operation scenarios.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI041  
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TUPRI052 Analysis of Single Bunch Measurements at the ALBA Storage Ring impedance, synchrotron, undulator, simulation 1686
 
  • T.F.G. Günzel, U. Iriso, F. Pérez
    CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
  • E. Koukovini-Platia, G. Rumolo
    CERN, Geneva, Switzerland
  
  Measurements of the vertical single bunch mode detuning and the TMCI threshold at zero chromaticity were carried out and their results were compared to the theoretical expectation. Around 65% of the found mode detuning can be explained by a developed transverse impedance model. A good bunch length parametrisation with current contributed essentially to this result. The analysis of single bunch measurements at non-zero chromaticity will also be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI052  
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TUPRI055 Theoretical Analysis of Metamaterial Insertions for Resistive-wall Beam-coupling Impedance Reduction impedance, insertion, coupling, interface 1695
 
  • A. Danisi, R. Losito, A. Masi, B. Salvant, C. Zannini
    CERN, Geneva, Switzerland
  
  Resistive-wall impedance usually constitutes a significant percentage of the total beam-coupling impedance budget of many accelerator structures (e.g. for LHC, it can be more than 50%). Reduction techniques for resistive-wall components entail high electrical-conductivity coatings. This paper proposes the use of metamaterials, having negative values of magnetic permeability or dielectric permittivity (or both), for sensibly reducing or theoretically nearly cancelling the resistive-wall component of beam-coupling impedance. The proposed approach is developed by means of an equivalent transmission-line model, whose results show the potential reduction of both longitudinal and transverse impedance when using metamaterial insertions. The effects on the real and imaginary part have been singled out. The effectiveness of such materials is discussed both for negative-permittivity and for negative-permeability cases, which actually show different impacts and can be then target of proper engineering. This first-stage study opens the possibility of considering metamaterials for impedance mitigation or for setting up proper experimental setups.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI055  
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TUPRI062 The Mode Matching Technique Applied to the Transverse Beam Coupling Impedance Calculation of Azimuthally Symmetric Devices of Finite Length impedance, cavity, coupling, simulation 1714
 
  • N. Biancacci, E. Métral, B. Salvant, C. Zannini
    CERN, Geneva, Switzerland
  • M. Migliorati, L. Palumbo
    URLS, Rome, Italy
  • V.G. Vaccaro
    Naples University Federico II and INFN, Napoli, Italy
  
  The infinite length approximation is often used to simplify the calculation of the beam coupling impedance of accelerator elements. This is expected to be a reasonable assumption for devices whose length is greater than the transverse dimension but may be a less accurate approximation for segmented devices. In this contribution we present the extension of the study of the beam coupling impedance of a finite length device to the transverse plane. In order to take into account the finite length, we decompose the fields in the cavity and in the beam pipe into a set of orthonormal modes and apply the Mode Matching method to obtain the impedance. To validate our method, we will present comparisons between analytical formulas and 3D electromagnetic CST simulations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI062  
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TUPRI063 Electromagnetic Simulations for Non-ultrarelativistic Beams and Application to the CERN Low Energy Machines impedance, coupling, simulation, space-charge 1718
 
  • C. Zannini, N. Biancacci, T.L. Rijoff, G. Rumolo
    CERN, Geneva, Switzerland
  • T.L. Rijoff
    TU Darmstadt, Darmstadt, Germany
  
  In the framework of the PS-Booster upgrade project an accurate impedance model is needed in order to determine the effect on the beam stability and assess the impact of the new devices to be installed in the machine. CST 3-D EM simulations are widely used to estimate the impedance contribution of the different devices along the CERN accelerator complex. Unlike the highly relativistic case, in which the reliability of the EM solver has been proved in many specific cases by comparing simulations with analytical results, the nonrelativistic case has been so far not yet benchmarked. In order to use systematically CST 3-D EM simulations for the PS-Booster, or even lower energy machines like the antiproton decelerator ELENA, a validation campaign has been carried out. The main complication to single out the beam coupling impedance, as resulting from the interaction of the beam with the surroundings, consisted of removing reliably the strong contribution of the direct space charge of the source bunch, which is included in the EM calculation. The simulation results were then benchmarked with the analytical results for the case of a PEC cylindrical tube and of a ferrite loaded kicker.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI063  
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TUPRI094 Experiments of Laser Pointing Stability in Air and in Vacuum to Validate Micrometric Positioning Sensor laser, experiment, alignment, linear-collider 1793
 
  • G. Stern, H. Mainaud Durand, D. Piedigrossi, J. Sandomierski, M. Sosin
    CERN, Geneva, Switzerland
  • A. Geiger, S. Guillaume
    ETH, Zurich, Switzerland
  
  Aligning accelerator components over 200m with 10 μm accuracy is a challenging task within the Compact Linear Collider (CLIC) study. A solution based on laser beam in vacuum as straight line reference is proposed. The positions of the accelerator’s components are measured with respect to the laser beam by sensors made of camera/shutter assemblies. To validate these sensors, laser pointing stability has to be studied over 200m. We perform experiments in air and in vacuum in order to know how laser pointing stability varies with the distance of propagation and with the environment. The experiments show that the standard deviations of the laser spot coordinates increase with the distance of propagation. They also show that the standard deviations are much smaller in vacuum (8 μm at 35m) than in air (2000 μm at 200m). Our experiment validates the concept of laser beam in vacuum with camera/shutter assembly for micrometric positioning over 35m. It also gives an estimation of the achievable precision.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI094  
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WEOAA02 Development of the Very Short Period Undulators undulator, radiation, electron, photon 1845
 
  • S. Yamamoto
    KEK, Ibaraki, Japan
  
  We have been exploring a method to fabricate very short period undulators, a period length of which is one order-of-magnitude shorter than the ordinary period of several cm. We are developing a plate-type magnet some 100mm long with a period length of 4mm. We selected this period length since we can generate 12-keV radiation with the first harmonic of this undulator in the 2.5-GeV storage ring. A multi-pole magnetizing method was applied to magnetizing this plate: a periodic undulator field (of 4-mm period in this case) was generated by pulsed electro-magnets, and was transcribed into the plate. The magnetization procedure allows the undulator field to be obtained in a very short gap between the pair of opposing plates, which is also one order-of-magnitude shorter than a gap in the ordinary undulators. We report the magnetization method to obtain a very short period and present the test results. The calculated spectrum of the radiation from the measured field compares well with that from an ideal magnetic field in the region of the fundamental radiation in case of 2.5-GeV energy of the electron beam.  
slides icon Slides WEOAA02 [5.189 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOAA02  
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WEIB02 RF Sub-Systems for Cargo and Vehicle Inspection linac, detector, photon, scattering 1917
 
  • D.J. Mistry, T.A. Cross, C.R. Weatherup
    e2v, Chelmsford, Essex, United Kingdom
  
  X-ray screening for security is a well-established inspection technique. Whilst in terms of fielded systems the vast majority consist of low energy X-ray sources, typically used for hand baggage or mail screening. There is a smaller but high value niche market servicing the requirements for border security, and cargo and vehicle inspection (CVI). This latter application requires higher X-ray energies of up to 10 MeV using an electron linear accelerator (linac) source to penetrate fully loaded shipping containers. Increasingly, methods are required to improve throughput and provide a higher level of material discrimination during inspection. This paper will briefly review the elements required to make an effective X-ray source, whilst outlining the RF technology required to drive a linac-based X-ray security system. Following this, potential new developments in radiofrequency (RF) sub-systems will be discussed in the context of user benefits.
Abstract redrafted 10.6.14
Original abstract: redrafted 6.12.13. 'The purpose of this presentation is to provide an understanding of global industry security systems and the role of accelerators…' 		 
slides icon Slides WEIB02 [5.892 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEIB02  
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WEIB03 How To Produce 100 Superconducting Modules for the European XFEL in Collaboration and with Industry cavity, quadrupole, SRF, controls 1923
 
  • H. Weise
    DESY, Hamburg, Germany
  
  European XFEL accelerator module production is in almost full swing by the time of IPAC 2014. This is the first project of this size that includes many partner laboratories and transfer of technology for mass superconducting RF cavity and accelerator module production to industry. This talk will illustrate the organization of the production and the lessons learned, illuminating what one should or would do differently for future projects.  
slides icon Slides WEIB03 [11.584 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEIB03  
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WEPRO006 Beam-driven Terahertz Source based on Open Ended Waveguide with a Dielectric Layer radiation, wakefield, optics, experiment 1949
 
  • A.V. Tyukhtin, S.N. Galyamin, V.V. Vorobev
    Saint-Petersburg State University, Saint-Petersburg, Russia
  • S.P. Antipov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S. Baturin
    LETI, Saint-Petersburg, Russia
  
  Funding: Work is supported by the Grant of the President of Russian Federation (MK-273.2013.2) and the Russian Foundation for Basic Research (Grant No. 12-02-31258).
Electromagnetic waves with frequencies from 0.1 THz to 10 THz (usually called the Terahertz gap) are of great importance for a number of scientific and practical applications. Different techniques are known allowing generating these frequencies. However, a current trend of physics and industry is to fill this gap with more powerful and efficient sources. For example, recent experiments have shown promising THz generation in dielectric loaded structures*. Developing this area, we consider the THz emitting scheme where an ultrarelativistic charge exits the open end of a cylindrical waveguide with a dielectric layer and produces THz waves in a form of Cherenkov radiation. The end of the waveguide is supposed to be either orthogonal to the structure axis or skewed. To obtain THz frequencies from waveguides with centimeter or millimeter radii, we consider high order modes. We present typical field patterns (in the Fraunhofer zone) and show that the aperture of the vacuum channel gives, as a rule, the main contribution. We also give simple expressions for the angle of the main pattern lobe.
* S. Antipov et al., Appl. Phys. Lett. 100, 132910 (2012). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO006  
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WEPRO014 The Installations of the In-vacuum Kicker System of the Booster Injection Section in TPS kicker, booster, injection, extraction 1971
 
  • C.S. Chen, C.K. Chan, K.H. Hsu, Y.T. Huang, Y.-H. Liu, C.S. Yang
    NSRRC, Hsinchu, Taiwan
  
  The installations of the In-Vacuum kicker system of the booster injection in TPS are presented in this article. Due to the more than 20 kV operation voltages and precise positioning requirements, the insulations and positioning systems are designed with more attentions. Although increasing the gap between high potential parts and ground could provide enough withstanding voltage, on the other hand, the insufficient space and vacuum requirements limit the sizes of insulators. Therefore, lots of effort have been done to deal with these conflicts. All assembling processes will be described in this paper as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO014  
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WEPRO022 Modal Analysis of Helical Undulator Radiation In Cylindrical Waveguide radiation, undulator, FEL, linac 1989
 
  • T.L. Vardanyan, M. Ivanyan, V. Sahakyan, A.V. Tsakanian, G.S. Zanyan
    CANDLE SRI, Yerevan, Armenia
  
  The coherent radiation of the relativistic electron beam with helical orbit in circular waveguide is studied. The radiation field configuration is obtained using modal expansion technique. For short electron bunches the coherent part of radiation is evaluated. The coherent radiation effects on the bunch performance are analyzed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO022  
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WEPRO029 Developing of Advanced Magnet Structures for Cryogenic in Vacuum Permanent Magnet Undulators undulator, permanent-magnet, cryogenics, electron 2004
 
  • C. Kuhn, J. Bahrdt, A. Gaupp, M. Scheer, B. Schulz
    HZB, Berlin, Germany
  
  Cryogenic in vacuum permanent magnet undulators with periods less than 10 mm and correspondingly narrow gaps require tighter geometric and magnetic tolerances and complex pole designs from different materials to achieve the needed high field strengths. We use new mechanic designs and manufacturing technologies for magnet and pole assembly. We develop new precise and UHV-compatible joining methods which are different from the current approaches which are based on mechanical clamping or gluing. . We examine the mechanical and magnetic properties by performing tests and discuss the results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO029  
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WEPRO031 Design and Commissioning of the FLASH2 Undulators undulator, FEL, controls, operation 2007
 
  • A. Schöps, O. Bilani, T. Ramm, M. Tischer, S. Tripathi, P. Vagin
    DESY, Hamburg, Germany
  
  This paper reports about aspects of design, manufacturing, and commissioning of the 12 FLASH2 variable gap undulator segments. The accuracy of gap drive and encoder systems was tested by magnetic measurements; changes in the phase error proved to be a highly sensitive probe to verify a reproducibility of 1 μm. After magnetic tuning of the IDs, the remaining gap dependence in the field integrals could be successfully compensated by corrector coils. Inconsiderate handling of components during assembling necessitated an elaborate demagnetisation process before the tuning could start.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO031  
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WEPRO034 Magnetic Measurement Developments for Undulators undulator, quadrupole, laser, alignment 2016
 
  • P. Vagin, P. Neumann, M. Tischer
    DESY, Hamburg, Germany
  
  FLASH2 is an extension of the present VUV-FEL facility at DESY. It includes a separate tunnel with a 12 x 2.5m = 30m long planar hybrid undulator. The undulators have 31.4mm period length and 1T field at a minimum gap of 9mm. The paper presents recent progress in the magnetic measurements of these undulators. Several specific details of the measurement tools will be discussed like peculiarities in the Hall probe calibration and noise, positioning accuracy and synchronization of voltage measurement with probes movement during scan, noise issues of various voltage integrators for stretched wire and search coil measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO034  
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WEPRO035 Radiation Damage of Undulators at PETRA III undulator, radiation, wiggler, damping 2019
 
  • P. Vagin, O. Bilani, A. Schöps, M. Tischer, S. Tripathi, T. Vielitz
    DESY, Hamburg, Germany
  
  In the new octant of PETRA~III, there are 14 undulator beamlines covering photon energy range from 0.3keV to 150keV. There are also 80m of damping wigglers in order to achieve a low emittance of 1nmrad. Some of these devices, operating at PETRAIII since 2008, accumulated total radiation doses of about 100kGy. Visible corrosion at the magnet structures of some permanent magnet undulators setting in after a few years and a high dose rate measured regularly by thermoluminescent dosimeters (TLDs) gave reason to inspect the magnetic field of all insertion devices in the PETRA tunnel. This paper presents details of the magnetic field degradation caused by radiation damage to the undulator magnets. For some undulators changes in the spectral properties of the generated light were observed. It was measured with different taper settings in order to partly compensate the nonuniform demagnetization along the structure. The results are compared with the data from the sFLASH undulators and measurements of special 3 pole "sacrificial" undulator, installed in FLASH. Its magnetic field is periodically remeasured and shows field amplitude decrease of 1% per 16kGy accumulated dose.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO035  
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WEPRO045 Design of a System at NSRRC to Measure the Field for an In-vacuum Cryogenic Undulator with Permanent Magnet laser, alignment, undulator, timing 2041
 
  • C.K. Yang, C.-H. Chang, T.Y. Chung, J.C. Huang, C.-S. Hwang, Y.Y. Lin
    NSRRC, Hsinchu, Taiwan
  
  A cryogenic undulator with a permanent magnet (CPMU) is an important insertion device now under construction at NSRRC. For an undulator of this kind, the distribution of the magnetic field must be measured along the axis; the phase error, trajectory and photon flux must be calculated after the magnetic arrays are installed in the vacuum chamber and cooled to cryogenic temperature. We developed a Hall-probe system to measure the magnetic field in an evacuated environment; this system uses lasers and stages to monitor and to correct dynamically the positions of the Hall probe. All components installed inside the vacuum chamber are compatible with an environment of high vacuum and low temperature. The details of the design and completed fabrication are presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO045  
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WEPRO047 A New Cooling System for Cryocooled Permanent Magnet Undulators at Diamond Light Source undulator, operation, cryogenics, electron 2047
 
  • E.C. Longhi, A.G. Miller, E.C.M. Rial, A.J. Rose, J.C. Schouten, C.W. Thompson, A. Thomson, J.H. Williams
    DLS, Oxfordshire, United Kingdom
  • C. Monroe
    Monroe Brothers Ltd., Moreton-in-Marsh, United Kingdom
  
  Cryocooled permanent magnet undulators (CPMUs) using NdFeB magnets around 150K were first proposed by Hara*. These are cooled by using either GM cryocoolers or circulating sub-cooled liquid nitrogen. Due to the heat load from radiation and wakefield heating from the electron beam, temperature gradients can develop along the length of the magnet girders which could be as large as several degrees for the Diamond Light Source (DLS) storage ring operating parameters. Some grades of the magnetic material (NdxPr1-x)2Fe14B have remanence curves versus temperature which increase significantly for temperatures below 150K with peaks below 80K**. This means that the operating temperature of a CPMU using this material can be close to the boiling point of liquid nitrogen. The proposed cooling system for the new DLS CPMU is based on a thermosiphon allowing nitrogen to boil inside the cooling channels without a circulating pump. This has the advantage of absorbing large amounts (>250W) of heat with very small temperature gradients. We report here the results of a prototype magnet beam cooled with a thermosiphon producing a temperature gradient of less than 0.05K along a 2m beam at ~77K.
* T. Hara et al., Phys Rev Spec Top. Accelerator & Beam, Vol 7, 2004.
** J. Bahrdt et al., AIP Conf. Proc., SRI 2009, Melbourne Australia, vol. 1234, pp. 499-502, 2010. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO047  
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WEPRO049 Experience of Operating a Superconducting Undulator at the Advanced Photon Source undulator, photon, operation, storage-ring 2053
 
  • Y. Ivanyushenkov, K.C. Harkay
    ANL, Argonne, Ilinois, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
A superconducting test undulator SCU0 was installed into the storage ring of the Advanced Photon Source (APS) in December 2012 and has been in user operation since January 2013. The first year's experience of operating such a novel insertion device at the APS is summarized in this paper. The performance of the SCU0 as a photon source is presented. The measured heat load from the electron beam is described together with the observed cryogenic behavior of the device. The effect of the SCU0 on the APS electron beam is also presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO049  
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WEPRO092 Comparisons and Simulations of Superconducting Dipole Magnets for JINR Carbon Ion Gantry dipole, ion, synchrotron, simulation 2174
 
  • E. Syresin, N.A. Morozov, D. Shvidkiy
    JINR, Dubna, Moscow Region, Russia
  
  A medical complex for carbon ion therapy has been developed in the JINR based on the own technology of the superconducting ion synchrotron - Nuclotron. One important feature of this project is related to the application of superconducting gantry. In the project, two schemes of superconducting gantries have been considered. In the first scheme, the last gantry element is supposed to be represented by a superconducting magnet with a scan region in it of 20 × 20 cm. In the second scheme the gantry consists of four 45°bending sections, each including two similar dipole magnets of a low aperture (about 120 mm). Such gantries are intended for multiple raster scanning with a wide carbon beam and the technique of layer wise irradiation with a spread out Bragg peak of several mm. The comparison and simulation of superconducting dipole magnet for JINR carbon ion gantry is under discussion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO092  
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WEPRO107 Positron Annihilation Spectroscopy at the LEPTA Facility positron, electron, background, scattering 2215
 
  • P. Horodek
    JINR/DLNP, Dubna, Moscow region, Russia
  • A.G. Kobets, I.N. Meshkov, O. Orlov, A.A. Sidorin
    JINR, Dubna, Moscow Region, Russia
  
  Since 2009 year the LEPTA facility at Joint Institute for Nuclear Research in Dubna is operated with positron beam. Today it is developed into two directions. The first one is getting orthopositronium flux in flight. Slow positrons from 22Na source are accumulated in Surko trap and then are injected into the ring where they should overlap with electrons from the single-pass electron beam. In this way the flux of orthopositronium atoms will appear and will be observed in the process of registration of gamma quanta from annihilation process. The second group of works focuses on using the positron injector for Positron Annihilation Spectroscopy (PAS) applications. This method is dedicated to detection of structural defects as vacancies in the solid body lattice. The latest progress of this technique is strictly connected with measurements of PAS characteristics using positron beams. The progress in the LEPTA development, the first results obtained in the PAS, idea and actual state of works concerning the construction of the pulsed positron beam will be presented. The creation of pulsed positron beams is the modern tendency in the PAS domain.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO107  
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WEPME004 Prediction of Severe Electron Loading of High-gradient Accelerating Structures based on Field Emission Measurements of Nb and Cu Samples electron, cavity, high-voltage, factory 2258
 
  • S. Lagotzky, G. Müller
    Bergische Universität Wuppertal, Wuppertal, Germany
  
  Funding: The work is funded by BMBF project 05H12PX6.
Enhanced field emission (EFE) limits the performance of both superconducting and normal conducting high-gradient accelerating structures. Systematic field emission scanning microscopy and correlated SEM/EDX measurements of relevant Nb and Cu samples have revealed particulates and surface irregularities with field enhancement factors b = 10 - 90 as origin of EFE. Based on sufficient emitter statistics, an exponential increase of the emitter number density N with increasing surface field (E) was found. This allows a prediction of the EFE loading of future ILC and CLIC accelerating structures by scaling of N to relevant E and using a weighted integration over the high-field cavity surface. Accordingly, an electropolished (Ra < 300 nm) and dry-ice cleaned (DIC) TESLA-shape 9-cell 1.3 GHz Nb cavity * will still suffer from EFE at Eacc = 35 MV/m (N = 0.3 /cm² at Epeak = 70 MV/m). Moreover, a diamond-turned, chemically etched and DIC 11.2 GHz Cu structure ** will breakdown at Eacc = 100 MV/m (N = 20 /cm² at Epeak = 243 MV/m). Possible improvements, i.e. by emitter processing will be discussed.
* ILC Technical Design Report (2013)
** A. Grudiev and W. Wuensch, Proceedings of LINAC2010, Tsukuba, Japan, pp. 211 - 213 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME004  
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WEPME005 Enhanced Field Emission and Emitter Activation on Flat Dry-ice Cleaned Cu Samples site, electron, factory, gun 2261
 
  • S. Lagotzky, G. Müller, P. Serbun
    Bergische Universität Wuppertal, Wuppertal, Germany
  • S. Calatroni, T. Muranaka
    CERN, Geneva, Switzerland
  
  Enhanced field emission (EFE), resulting in dark currents and electric breakdowns, is one of the main gradient limitations for the CLIC accelerating structures (actual design Eacc = 100 MV/m, Epeak = 240 MV/m *). Measurements on diamond-turned, flat (Ra = 158 nm) Cu samples showed first EFE at surface fields Es = 130 MV/m. In order to reduce EFE, we have installed a commercial dry ice cleaning (DIC) system in a clean room environment (class iso 5). Accordingly, the number density of emitters (N) was significantly decreased by DIC from N = 52 /cm² to N = 12 /cm² at Es = 190 MV/m. Furthermore we have tested two diamond-turned and chemically etched (SLAC treatment, Ra = 150 nm) Cu samples after DIC resulting in EFE onset at 230 MV/m. Locally measured I(V) curves of the strongest emitters yielded field enhancement factors b = 10 – 90 (10 – 85) on the diamond-turned (chemically etched), respectively. SEM and EDX investigations of the located emission sites revealed surface defects and few particulates (Al, Ca, Si) as origin of the EFE. Moreover, strong emitter activation effects were observed. A possible breakdown mechanism based on this EFE activation will be discussed.
* A. Grudiev and W. Wuensch, Proceedings of LINAC2010, Tsukuba, Japan, pp. 211 - 213 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME005  
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WEPME011 2 kW Balanced Amplifier Module for a 30 kW Solid-State Pulsed RF Power Amplifier at 352 MHz controls, operation, linac, proton 2279
 
  • A. Kaftoosian, P.J. González
    ESS Bilbao, LEIOA, Spain
  
  Design and development of a 30 kW, 352 MHz pulsed RF solid-state power amplifier to be utilized for feeding re-bunching cavities in proton linac, is in progress at ESS-Bilbao. This modular transmitter is based on in-phase combination of compact, water-cooled 2 kW RF power modules, each one consists of two combined LDMOS transistors in balanced configuration. The modules include individual bias control, measurement and supply circuits. Gate modulation is foreseen to increase efficiency in pulsed regime that is up to 3ms RF pulse width and 10% duty cycle. The 2 kW RF power module has been developed and the test results are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME011  
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WEPME012 Solid-State Amplifier Development at FREIA operation, impedance, cryomodule, network 2282
 
  • D.S. Dancila, A. Rydberg
    Uppsala University, Department of Engineering Sciences, Uppsala, Sweden
  • A. Eriksson, V.A. Goryashko, L.F. Haapala, R.J.M.Y. Ruber, R. Wedberg, R.A. Yogi, V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  
  The FREIA laboratory is a Facility for REsearch Instrumentation and Accelerator development at Uppsala University, Sweden, constructed recently to test and develop superconducting accelerating cavities and their high power RF sources. FREIA's activity target initially the European Spallation Source (ESS) requirements for testing spoke cavities and RF power stations, typically 400 kW per cavity. Different power stations will be installed at the FREIA laboratory. The first one is based on vacuum tubes and the second on a combination of solid state modules. In this context, we investigate different related aspects, such as power generation and power combination. For the characterization of solid-state amplifier modules in pulsed mode, at ESS specifications, we implemented a Hot S-parameters measurement set-up, allowing in addition the measurement of different parameters, such as gain and efficiency. We developed also a new solid-state amplifier module at 352 MHz, using commercially available LDMOS transistors. Preliminary results show a drain efficiency of 71% at 1300 W pulsed output power.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME012  
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WEPME015 High-gradient Test Results from a CLIC Prototype Accelerating Structure: TD26CC damping, linac, accelerating-gradient, target 2285
 
  • W. Wuensch, A. Degiovanni, S. Döbert, W. Farabolini, A. Grudiev, J.W. Kovermann, E. Montesinos, G. Riddone, I. Syratchev, R. Wegner
    CERN, Geneva, Switzerland
  • A. Solodko
    JINR, Dubna, Moscow Region, Russia
  • B.J. Woolley
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  
  The CLIC study has progressively tested prototype accelerating structures which incorporate an ever increasing number of features which are needed for a final version installed in a linear collider. The most recent high power test made in the CERN X-band test stand, Xbox-1, is a of a CERN-built prototype which includes damping features but also compact input and output power couplers, which maximize the overall length to active gradient ratio of the structure. The structure’s high-gradient performance, 100 MV/m and low breakdown rate, matches previously tested structures validating both CERN fabrication and the compact coupler design.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME015  
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WEPME016 Experience Operating an X-band High-Power Test Stand at CERN klystron, network, controls, LLRF 2288
 
  • W. Wuensch, N. Catalán Lasheras, A. Degiovanni, S. Döbert, W. Farabolini, J.W. Kovermann, G. McMonagle, S.F. Rey, I. Syratchev, L. Timeo
    CERN, Geneva, Switzerland
  • J. Tagg
    National Instruments Switzerland, Ennetbaden, Switzerland
  • B.J. Woolley
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  
  CERN has constructed and is operating a klystron-based X-band test stand, called Xbox-1, dedicated to the high-gradient testing of prototype accelerating structures for CLIC and other applications such as FELs. The test stand has now been in operation for a year and significant progress has been made in understanding the system, improving its reliability, upgrading hardware and implementing automatic algorithms for conditioning the accelerating structures. This experience is reviewed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME016  
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WEPME018 CERN Vacuum System Activities during the Long Shutdown 1: The LHC’s injector chain. linac, ion, operation, gun 2291
 
  • J.A. Ferreira Somoza, P. Chiggiato
    CERN, Geneva, Switzerland
  
  During the long shutdown 1 (LS1), several maintenance, consolidation and upgrade activities have been carried out in LHC’s injector chain. Each machine has specific vacuum requirements and different history, which determine the present status of the vacuum components, their maintenance and consolidation needs. The present work presents the priorities agreed at the beginning of the LS1 period and their implementation. Of particular relevance are the interventions in radioactive controlled areas where several leaks due to stress corrosions stopped the operations in the past years. The strategy to reduce the collective dose is presented, in particular the use of remote controlled robots. An important part of the work performed during this period involves supporting other teams (acceptance tests, new equipment installation, etc.). Finally, as a result of the LS1 experience, a medium to long term strategy is depicted, focusing on the preparation of the next shutdown (LS2) and the integration of LINAC4 in the injector chain during the same period.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME018  
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WEPME025 Design and Performance of Ultimate Vacuum System for the AREAL Test Facility gun, cathode, dipole, electron 2311
 
  • A.A. Gevorgyan, V.S. Avagyan, B. Grigoryan, T.H. Mkrtchyan, A.S. Simonyan, V. V. Vardanyan
    CANDLE SRI, Yerevan, Armenia
  
  The design specification of the AREAL test facility require the residual pressure at the level of 1nTorr with beam through entire vacuum chamber. We present the main features of the vacuum system, including the design and fabrication peculiarities of the dedicated components like dipole magnet stainless steel vacuum chamber and the cubes for beam diagnostic stations. The philosophy and instrumentation of the vacuum system are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME025  
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WEPME026 Layout of the Vacuum System for a New ESRF Storage Ring lattice, storage-ring, radiation, insertion 2314
 
  • M. Hahn, J.C. Biasci, H.P. Marques
    ESRF, Grenoble, France
  
  The proposed 7-bend achromat lattice for the new 6 GeV electron storage ring of the European Synchrotron Radiation Facility imposes a change of the entire vacuum system. Small bore magnets will require low conductance vacuum chambers. Conventional vacuum pumps will have to be assisted by distributed pumping provided by Non-Evaporable Getter (NEG) coating. The time constraints for design, prototyping, pre-assembly, installation and commissioning of the new systems require simple solutions and the use of existing expertise where possible. In this paper the draft layout of the vacuum system will be explained, information about the expected dynamic pressure distribution and conditioning will be given. Some technical solutions to resolve specific issues arising from the small vacuum chamber dimensions and the dense arrangement of components are described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME026  
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WEPME028 Systematic Measurement of the Pumping Capabilities of Cryogenic Surfaces radiation, cryogenics, simulation, operation 2317
 
  • F. Chill, O.K. Kester
    IAP, Frankfurt am Main, Germany
  • L.H.J. Bozyk, O.K. Kester, P.J. Spiller
    GSI, Darmstadt, Germany
  
  The quality of the beam vacuum is crucial for the stable operation of synchrotrons with high intensity heavy ions. Cryogenic surfaces are capable of pumping residual gases by cryocondensation until the saturated vapor pressure (SVP) is reached. Even at LHe temperatures the SVP of hydrogen is too high. If the surface coverage is sufficiently low, residual gas can also be bound by cryosorption, yielding in acceptable low pressures. These pumping capabilities can be described by two parameters, both dependent on surface temperature and coverage: The sticking probability (SP), that is the chance of an impinging gas particle to be bound, and the mean sojourn time (MST) of a particle on the surface. To acquire these parameters, an experimental setup is currently built at GSI. It consists of a cryogenic chamber, cooled by a cold head and a warm part with vacuum diagnostics and gas inlet. It allows monitoring the pumping speed and also the equilibrium pressure of the cryogenic part from which the SP and the MST can be deducted. The results will be used to further improve the accuracy of the dynamic vacuum simulations in cryogenic areas of particle accelerators.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME028  
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WEPME029 Development of a Field Emitter-based Extractor Gauge for the Operation in Cryogenic Vacuum Environments cryogenics, ion, cathode, operation 2320
 
  • M. Lotz, O.K. Kester, St. Wilfert
    GSI, Darmstadt, Germany
  
  This paper presents an investigation of a CNT emitter-based extractor gauge which is designed for pressure reading in cryogenic ultra-high vacuum systems. The results show that the modified gauge works well in both room temperature and cryogenic vacuum environments. Furthermore, it could be demonstrated that the modified gauge responds much more sensitive to small pressure fluctuations in cryogenic environments than the same gauge type having a hot-filament cathode.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME029  
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WEPME030 Design and Construction of a Prototype Sputter ion Pump in ILSF ion, cathode, operation, electron 2323
 
  • O. Seify, H. Ghasem, S. Kashani, J. Rahighi
    ILSF, Tehran, Iran
  • H. Ghasem
    IPM, Tehran, Iran
  
  Design and construction process of special kind of sputter ion pump is described briefly in this paper. In order to investigate the optimization of effective parameters in choosing and designing ILSF ion pumps, this pump has been designed and manufactured. By optimizing some parameters such as dimension and shape of penning cells, anode voltage, magnetic field and internal structure of pump, it is possible to significantly decrease the cost of construction and operation of synchrotron vacuum system. One of the most important advantages of this design, is that the initial parameters and finally internal structure of the prototype pump are changeable easily. The effect of parameters like anode voltage, magnetic field etc. on pumping speed and final pressure are described. With the existing optimization it is expected that an ultimate pressure of 1x10-11 Torr could be achieved.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME030  
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WEPME033 Search for New e-cloud Mitigator Materials for High Intensity Particle Accelerators electron, experiment, embedded, impedance 2332
 
  • R. Cimino, S.T. O'connor, A.L. Romano
    INFN/LNF, Frascati (Roma), Italy
  • V. Baglin, G. Bregliozzi, R. Cimino
    CERN, Geneva, Switzerland
  • M.R. Masullo
    INFN-Napoli, Napoli, Italy
  • S. Petracca, A. Stabile
    INFN-Salerno, Baronissi, Salerno, Italy
  
  Electron cloud is an ubiquitous effect in positively charged particle accelerators and has been observed to induce unwanted detrimental impacts on beam quality, stability, vacuum etc. A great effort has been recently devoted to the search of new material morphology and/or coatings which can intrinsically mitigate beam instabilities deriving from electron cloud effects. In this context, we present some characterization of Cu foams, available from the market, and their qualification in terms of their vacuum behavior, impedance, secondary electron yield, gas desorption etc. More experimental effort is required to finally qualify foams as a mature technology to be integrated in accelerator environments. But, our preliminary results suggests that, when compatible with geometrical constrains, Cu foams can be utilized when low desorption yields are required and as e-cloud moderator in future particles accelerators.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME033  
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WEPME035 Beam Loss Suppression by Improvement of Vacuum System in J-PARC RCS injection, ion, synchrotron, linac 2338
 
  • J. Kamiya, M. Kinsho, S. Noshiroya, K. Yamamoto
    JAEA/J-PARC, Tokai-mura, Japan
  
  In high power beam accelerators, pressure of the beam line directly affects the amount of the beam loss. For example, in the early 1970’s in CERN’s Intersecting Storage Ring (ISR), the ion-induced pressure bump produced the fall-off of the beam current. 3GeV synchrotron (RCS) in J-PARC is no exception. RCS is one of the most high power beam accelerators in the world. It aims the 1 MW beam power, which corresponds to the average and peak beam current of 333 uA and about 10 A, respectively. In the present stage, the injection line called L3BT line (Linac to 3GeV Beam Transport line), is the section, where the pressure notably produces the beam loss. In this line, H− beam from Linac was converted to H0 by charge stripping due to the interaction between H− beam and the residual gas molecules. Such H0 was not bended by the injection septum magnets and directly hit the vacuum wall. We decided to add the vacuum pumps in this line to reduce the residual gas molecules. We will present the effectivity of the additional pumps on the basis of the measured results of the pressure improvement and the beam loss suppression.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME035  
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WEPME036 Simulation of the Trajectory of Electrons in a Magnetron Sputtering System of TiN with CST Particle Studio cathode, electron, simulation, experiment 2341
 
  • J. Wang, L. Fan, Y.Z. Hong, W.L. Liu, X.T. Pei, K. Tang, Y. Wang, W. Wei, Y.H. Xu, B. Zhang
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Funding: National Nature Science Foundation of China under Grant Nos.11075157.
In the process of magnetron sputtering deposition, electromagnetic fields have an important influence on the trajectory of particle movement and the properties of the TiN thin film in many cases. Even for simple geometries, the analytical prediction for charged particles trajectories is extremely cumbersome, so numerical simulations are essential to obtain a better understanding of the possible effects and helpful to optimize the design of experimental facility and experimental process. A software of CST PARTICLE STUDIOTM has been used to simulate the effect of magnetic and electric fields on electrons trajectories in the process of film coating. According to the simulation results, the improvement measures of the system design and experimental process have been achieved. The author put forward the improvement measures on film coating process according to the simulation results. The result shows that it is feasible and convenient to use three dimensional tool in the simulation of trajectory of electrons in a magnetron sputtering system. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME036  
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WEPME037 Monte Carlo Simulations of Synchrotron Radiation and Vacuum Performance of the Max IV Light Source photon, simulation, radiation, synchrotron 2344
 
  • M. Ady, R. Kersevan
    CERN, Geneva, Switzerland
  • M.J. Grabski
    MAX-lab, Lund, Sweden
  
  In the MAX IV light-source in Lund, Sweden, the intense synchrotron radiation (SR) distributed along the ring generates important thermal and vacuum effects. By means of a Monte Carlo simulation package, which is currently developed at CERN, both thermal and vacuum effects are quantitatively analysed, in particular near the crotch absorbers and the surrounding NEG-coated vacuum chambers. Using SynRad+, the beam trajectory of the upstream bending magnet is calculated; SR photons are generated and traced through the geometry until their absorption. This allows an analysis of the incident power density on the absorber, and to calculate the photon induced outgassing. The results are imported to Molflow+, a Monte Carlo vacuum simulator that works in the molecular flow regime, and the pressure in the vacuum system and the saturation length of the NEG coating are determined using iterations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME037  
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WEPME038 Introduction to the Latest Version of the Test-particle Monte Carlo Code Molflow+ simulation, injection, software, cryogenics 2348
 
  • M. Ady, R. Kersevan
    CERN, Geneva, Switzerland
  
  The Test-Particle Monte Carlo code Molflow+ is getting more and more attention from the scientific community needing detailed 3D calculations of vacuum in the molecular flow regime mainly, but not limited to, the particle accelerator field. Substantial changes, bug fixes, geometry-editing and modelling features, and computational speed improvements have been made to the code in the last couple of years. This paper will outline many of these new features, and show examples of applications to the design and analysis of vacuum systems at CERN and elsewhere.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME038  
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WEPME039 Leak Propagation Dynamics for the HIE-ISOLDE Superconducting Linac cryomodule, linac, simulation, cathode 2351
 
  • G. Vandoni, M. Ady, M.A. Hermann, R. Kersevan, D.T. Ziemianski
    CERN, Geneva, Switzerland
  
  In order to cope with space limitations of existing infrastructure, the cryomodules of the HIE-Isolde superconducting linac feature a common insulation and beam vacuum, imposing the severe cleanliness standard of RF cavities to the whole cryostat. Protection of the linac vacuum against air-inrush from the three experimental stations through the HEBT lines relies on fast valves, triggered by fast cold cathode gauges. To evaluate the leak propagation velocity as a function of leak size and geometry of the lines, a computational and experimental investigation is being carried out at CERN. A 28 m long tube is equipped with strain gauges installed on thin-walled flanges, as well as fast reacting glow discharge and cold-cathode gauges. A leak is opened by the effect of a cutting pendulum, equipped with an accelerometer for data acquisition triggering, on a thin aluminium window followed by a calibrated orifice. The air inrush dynamics is simulated by Test-Particle Monte Carlo in the molecular regime and by Finite Elements fluid dynamics in the viscous regime.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME039  
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WEPME040 Development of Aluminium Vacuum Chambers for the LHC Experiments at CERN experiment, beam-losses, factory, electron 2354
 
  • M.A. Gallilee, P. Chiggiato, P. Costa Pinto, L.M.A. Ferreira, P. Lepeule, J. Perez Espinos, L. Prever-Loiri, A. Sapountzis
    CERN, Geneva, Switzerland
  
  Beam losses may cause activation of vacuum chamber walls, in particular those of the Large Hadron Collider (LHC) experiments. For the High Luminosity LHC, the activation of such vacuum chambers will increase. It is therefore necessary to use a vacuum chamber material which interacts less with the circulating beam. While beryllium is reserved for the collision point, a good compromise between cost, availability and transparency is obtained with aluminium alloys; such materials are a preferred choice with respect to austenitic stainless steel. Manufacturing a thin-wall aluminium vacuum chamber presents several challenges as the material grade needs to be machinable, weldable, leak-tight for small thicknesses, and able to withstand heating to 250°C for extended periods of time. This paper presents some of the technical challenges during the manufacture of these vacuum chambers and the methods for overcoming production difficulties, including surface treatments and NEG thin-film coating.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME040  
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WEPME041 Vacuum Acceptance Tests for the UHV Room Temperature Vacuum System of the LHC during LS1 injection, ion, accumulation, controls 2357
 
  • G. Cattenoz, V. Baglin, G. Bregliozzi, D. Calegari, P. Chiggiato, J.E. Gallagher, A. Marraffa
    CERN, Geneva, Switzerland
  
  During the CERN Large Hadron Collider (LHC) first long shut down (LS1), a large number of vacuum tests are carried out on consolidated or newly fabricated pieces of equipment. In such a way, the vacuum compatibility is assessed before installation in the UHV system of the LHC. According to the equipment’s nature, the vacuum acceptance tests consist in functional checks, leak tests, outgassing rate measurements, evaluation of contaminants by Residual Gas Analysis (RGA), pumping speed measurements, and qualification of the sticking probability of Non-Evaporable-Getter coating. In this paper, the methods used for the tests and the acceptance criteria are described. A summary of the measured vacuum characteristics for the tested components is also given.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME041  
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WEPME042 The LHC Vacuum Pilot Sectors Project electron, controls, radiation, detector 2360
 
  • B. Henrist, V. Baglin, G. Bregliozzi, P. Chiggiato
    CERN, Geneva, Switzerland
  
  The operation of the CERN Large Hadron Collider (LHC) at nominal beam parameters is expected for the next years (2015). Increased synchrotron-radiation stimulated-desorption and electron-cloud build-up are expected. A deep understanding of the interactions between the proton beams and the beampipe wall is mandatory to control the anticipated beam-induced pressure rise. A Vacuum Pilot Sector (VPS) has been designed to monitor the performance of the vacuum system with time. The VPS is installed along a double LHC room temperature vacuum sector (18 m long, 80 mm inner diameter beam pipes) and includes 8 standard modules, 1.4 m long each. Such modules are equipped with residual gas analysers, Bayard-Alpert gauges, photon and electron flux monitors, etc. The chosen modular approach opens the possibility of studying different configurations and implementing future modifications. This contribution will describe the apparatus, the control system designed to drive measurements and possible applications during the next LHC operational phase.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME042  
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WEPME043 Design and Qualification of Transparent Beam Vacuum Chamber Supports for the LHCb Experiment experiment, operation, factory, proton 2363
 
  • J.L. Bosch, P. Chiggiato, C. Garion
    CERN, Geneva, Switzerland
  
  Beryllium beam vacuum chambers pass through the aperture of the large dipole magnet and particle acceptance region of the LHCb experiment, coaxial to the LHC beam. At the interior of the magnet, a system of rods and cables supports the chambers, holding them rigidly in place, in opposition to the vacuum forces caused by their conical geometry. In the scope of the current upgrade program, the steel and aluminium structural components are replaced by a newly designed system, making use of Beryllium, in addition to a number of organic materials, and are optimized for overall transparency to incident particles. Presented in this paper are the design criteria, along with the unique design developments carried out at CERN, and furthermore, a description of the technologies procured from industrial partners, specifically in obtaining the best solution for the cable components.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME043  
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WEPME044 LHC Experimental Beam Pipe Upgrade during LS1 detector, experiment, injection, simulation 2366
 
  • G. Lanza, V. Baglin, G. Bregliozzi, P. Chiggiato
    CERN, Geneva, Switzerland
  
  The LHC experimental beam pipes are being improved during the ongoing long shutdown 1 (LS1). Several vacuum chambers have been tested and validated before their installation inside the detectors. The validation tests include: leak tightness, ultimate vacuum pressure, material outgassing rate, and residual gas composition. NEG coatings are assessed by hydrogen sticking probability measurement with the help of Monte Carlo simulations. In this paper the motivation for the beam pipe upgrade, the validation tests of the components and the results are presented and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME044  
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WEPME045 Assessment of New Components to be Integrated in the LHC Room Temperature Vacuum System experiment, injection, ion, operation 2369
 
  • G. Bregliozzi, V. Baglin, P. Chiggiato
    CERN, Geneva, Switzerland
  
  Integration of new equipment in the long straight sections (LSS) of the LHC must be compatible with the TiZrV non-evaporable getter thin film that coats most of the 6-km-long room-temperature beam pipes. This paper focus on two innovative accelerator devices to be installed in the LSS during the long shutdown 1 (LS1): the beam gas vertex (BGV) and a beam bending experiment using crystal collimator (LUA9). The BGV necessitates a dedicated pressure bump, generated by local gas injection, in order to create the required rate of inelastic beam-gas interactions. The LAU9 experiments aims at improving beam cleaning efficiency with the use of a crystal collimator. New materials like fibre optics, piezoelectric components, and glues are proposed in the original design of the two devices. The integration feasibility of these set-ups in the LSS is presented. In particular outgassing tests of special components, X-rays photoelectron spectroscopy, analysis of NEG coating behaviour in presence of glues during bake-out, and pressure profile simulations will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME045  
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WEPME046 The HIE-Isolde Vacuum System linac, cryomodule, controls, operation 2372
 
  • G. Vandoni, S. Blanchard, P. Chiggiato, K. Radwan
    CERN, Geneva, Switzerland
  
  The High Intensity and Energy Isolde (HIE-Isolde) project aims at increasing the energy and intensity of the radioactive ion beams (RIB) delivered by the present Rex-Isolde facility. Energy up to 10MeV/amu will be reached by a new post-accelerating, superconducting (SC) linac. Beam will be delivered via a HEBT to three experimental stations for nuclear physics. To keep the SC linac compact and avoid cold-warm transitions, the cryomodules feature a common beam and insulation vacuum. Radioactive ion beams require a hermetically sealed vacuum, with transfer of the effluents to the nuclear ventilation chimney. Hermetically sealed, dry, gas transfer vacuum pumps are preferred to gas binding pumps, for an optimized management of radioactive contamination risk during maintenance and intervention. The vacuum system of the SC-linac is isolated by two fast valves, triggered by fast reacting cold cathode gauges installed on the warm linac, the HEBT and the experimental stations. Rough pumping is distributed, while the HEBT turbomolecular pumps also share a common backing line. Slow pumpdown and ventilation of the cryomodules are studied to avoid particulate movement in the viscous regime.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME046  
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WEPME047 CERN Vacuum System Activities during the Long Shutdown 1: the LHC Beam Vacuum experiment, electron, cryogenics, collimation 2375
 
  • V. Baglin, G. Bregliozzi, P. Chiggiato, J.M. Jimenez, G. Lanza
    CERN, Geneva, Switzerland
  
  After the Long Shutdown 1 (LS1) and the consolidation of the magnet bus bars, the CERN Large Hadron Collider (LHC) will operate with nominal beam parameters. Larger beam energy, beam intensities and luminosity are expected. Despite the very good performance of the beam vacuum system during the 2010-12 physics run (Run 1), some particular areas require attention for repair, consolidation and upgrade. Among the main activities, a large campaign aiming at the repair of the RF bridges of some vacuum modules is conducted. Moreover, consolidation of the cryogenic beam vacuum systems with burst disk for safety reasons is implemented. In addition, NEG cartridges, NEG coated inserts and new instruments for the vacuum system upgrade are installed. Besides these activities, repair, consolidation and upgrades of other beam equipment such as collimators, kickers and beam instrumentations are carried out. In this paper, the motivation and the description for such activities, together with the expected beam vacuum performance after LS1, are described in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME047  
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WEPME048 Preliminary Design of the HiLumi-LHC Triplet Area Beam Screen shielding, optics, cryogenics, luminosity 2378
 
  • R. Kersevan, C. Garion, N. Kos
    CERN, Geneva, Switzerland
  
  The so-called beam screen (BS) is a proven solution for intercepting the thermal loads caused by the circulating beams in the cryogenically-cooled sections of the LHC and minimizing dynamic vacuum effects. The new triplet area foreseen for the HiLumi-LHC machine upgrade has the additional feature of needing internal tungsten shields to reduce the amount of collision debris which is deflected by the high-gradient triplet magnets towards the superconducting magnets' cold masses and coils. The very aggressive optics design, based on large beam separations, calls for a maximum of physical space to remain available to the counter rotating beams in the common BS. This places severe constraints to the fabrication and installation tolerances of the BS itself, in addition to affecting the design and routing of the cryogenic lines in the area. The latest version of the BS design will be shown and discussed, together with future plans for testing materials, fabrication procedures, and installation.
* The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME048  
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WEPME049 Coupled Simulations of the Synchrotron Radiation and Induced Desorption Pressure Profiles for the HiLumi-LHC Triplet Area and Interaction Points simulation, photon, electron, detector 2381
 
  • R. Kersevan, V. Baglin, G. Bregliozzi
    CERN, Geneva, Switzerland
  
  The HiLumi-LHC machine upgrade has officially started as an approved LHC project (see dedicated presentations at this conference on the subject). One important feature of the upgrade is the installation of very high-gradient triplet magnets for focusing the beams at the collision points of the two high-luminosity detectors ATLAS and CMS. Other important topics are new superconducting D1 magnets, installation of crab cavities, and re-shuffling of the dispersion suppression area. Based on the current magnetic lattice set-up and beam orbits, a detailed study of the emission of synchrotron radiation (SR) and related photon-induced desorption (PID) has been carried out. A significant amount of SR photons are generated by the two off-axis beams in the common vacuum chamber of the triplet area, about 57 m in length. Ray-tracing Montecarlo codes SYNRAD+ and Molflow+ have been employed in this study. The related PID pressure profiles will be shown, together with simulations using the code VASCO for the analysis of beam losses and background in the detectors, including electron cloud effects.
(*) The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME049  
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WEPME051 Development of the TPS Vacuum Interlock and Monitor Systems controls, storage-ring, photon, booster 2387
 
  • Y.C. Yang, B.Y. Chen, J.-R. Chen, Z.W. Chen, J. -Y. Chuang, G.-Y. Hsiung, T.Y. Lee
    NSRRC, Hsinchu, Taiwan
  
  The vacuum interlock and monitor systems of Taiwan Photon Source are designed to maintain the ultra-high vacuum condition and to protect the vacuum devices. The pressure readings of ionization gauges are taken as the judgment logic to control the opening and closing of sector gate valves so as to protect the ultra-high vacuum condition. Monitors of the water-cooling system and the chamber temperature serve to protect vacuum devices from radiation hazards. The preparation, installation and status of the interlock and monitor systems are presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME051  
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WEPME052 The Installation of TPS Booster Vacuum System booster, dipole, ion, synchrotron 2390
 
  • C.M. Cheng, B.Y. Chen, J.-R. Chen, G.-Y. Hsiung, S-N. Hsu, T.Y. Lee, Y.C. Yang
    NSRRC, Hsinchu, Taiwan
  • J.-R. Chen
    National Tsing Hua University, Hsinchu, Taiwan
  
  The booster of Taiwan Photon Source (TPS) is designed for 3GeV full energy injection ramped up from 150MeV. It is a synchrotron accelerator of 496.8m. The major vacuum system is elliptical tube made of 304 stainless steel. The inner cross section is 35*20 mm with 0.7 mm thickness. The elliptical tubes were chemical cleaned and ozonated water cleaned before installation. The bending tube was assembled and aligned into dipole magnet at laboratory. The BPM support and pumping chamber support was aligned with 0.3 mm deviation. The BPM chamber and pumping chamber was assembled firstly. The elliptical tube and bellows was installed to connect BPM, pumping chamber and bending chamber. The cold cathode gauge and TMP was mounted on pumping chamber. The pressure data and residual gas analysis will be described in the paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME052  
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WEPME054 Design and Fabrication of the Novel-type Ceramic Chamber site, HOM, detector, electron 2393
 
  • L.H. Wu, C.K. Chan, J.-R. Chen, G.-Y. Hsiung, S-N. Hsu, T.Y. Lee
    NSRRC, Hsinchu, Taiwan
  • J.-R. Chen
    National Tsing Hua University, Hsinchu, Taiwan
  
  A ceramic chamber of novel type has been designed and fabricated. The uniformity of its inner thin film of deposited metal is improved to have a thickness error about 1 %. The average straightness error of the chamber (length 550 mm) is developed to be less than 55 μm. To fabricate the ceramic chamber of novel type, we first cleaned and joined the two halves; the metal films were deposited by sputtering. These two halves were next sealed with a glass powder colloid to become a ceramic tube. The rate of outgassing of this colloid is 3.57×10-12 Torr L s−1 cm-2 after baking. The ceramic tube was connected to a stainless-steel flange with the aid of a glass powder colloid and TIG welding. This ceramic test chamber will be installed in the experimental system to analyze the residual gas.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME054  
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WEPME055 Residual Gas in the 14 m-long Aluminium Vacuum System of the Storage Ring of Taiwan Photon Source: toward Ultra-high Vacuum ion, cathode, storage-ring, photon 2396
 
  • T.Y. Lee, C.K. Chan, C.H. Chang, C.-C. Chang, S.W. Chang, Y.P. Chang, B.Y. Chen, J.-R. Chen, Z.W. Chen, C.M. Cheng, Y.T. Cheng, G.-Y. Hsiung, S-N. Hsu, H.P. Hsueh, C.S. Huang, Y.T. Huang, L.H. Wu, Y.C. Yang
    NSRRC, Hsinchu, Taiwan
  
  In the Taiwan Photon Source project, the storage ring includes 24 sectors (each of length 14 m) of an aluminium vacuum chamber system. The design, manufacture, cleaning, welding and assembly of the vacuum components were undertaken by the NSRRC vacuum group. The ultimate objective is to attain a leak-tight, ultra-high vacuum and a vacuum system with a small rate of outgassing. In this work, we used a residual-gas analyzer (RGA) to analyze the variation of residual gas during proceeding toward ultra-high vacuum. This process, which led the pressure down to ~10-11 torr, includes baking, operation of ion pumps, degassing of hot cathode gauges and activation of NEG pumps. When a sufficiently small low pressure is attained, the ion pumps are turned off to test the building up of pressure. The outgassing property and the variation of the residual gas of the aluminium chamber and the ion pumps can be measured.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME055  
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WEPME056 Further Optimisation of NEG Coatings for Accelerator Beam Chamber electron, injection, experiment, photon 2399
 
  • O.B. Malyshev, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  The non-evaporable getter (NEG) coating, invented at CERN in 90s, is used nowadays in many accelerators around the world. The main advantages of using NEG coatings are evenly distributed pumping speed, low thermal outgassing rates and low photon and electron stimulated gas desorption. The only downside of the NEG is its selective pumping: it pumps H2, CO, CO2 and some other gas species, but does not pump noble gases and hydrocarbons. However, in the accelerators where NEG coating could be beneficial, there is synchrotron radiation and photoelectrons that bombard vacuum chamber walls, it was found in our study that hydrocarbons can be pumped by NEG coating under electron and, most likely, photon bombardment. The detail and the results of this study are reported in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME056  
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WEPME057 The Secondary Electron Yield from Transition Metals electron, gun, collider, hadron 2403
 
  • S. Wang, M.D. Cropper
    Loughborough University, Loughborough, Leicestershire, United Kingdom
  • O.B. Malyshev, E.A. Seddon, R. Valizadeh, S. Wang
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Non-evaporable getter thin films, which are currently being used in the ultra-high vacuum system of the Large Hadron Collider, normally consist of Ti, Zr and V, deposited by physical vapour deposition. In this study, the secondary electron yield (SEY) of bulk Ti, Zr, V and Hf have been investigated as a function of electron conditioning. The maximum SEYs of as-received Ti, Zr, V and Hf, are respectively 1.96, 2.34, 1.72 and 2.32, these reduce to 1.14, 1.13, 1.44 and 1.18 after electron conditioning. Surface chemical composition was studied by X-ray photoelectron spectroscopy which revealed that surface conditioning by electron bombardment promotes the growth of a thin carbon layer on the surface and consequently reduces the SEY of the surface as a function of electron dose. Heating a vanadium sample to 250°C resulted in diffusion of oxygen into the bulk and induced formation of metal carbide at the surface. However, the SEY stays the same even after heat-induced surface chemistry modification. Prolonged electron conditioning increases the surface oxygen but the surface is still predominantly covered with a thin graphitic layer and hence the SEY stays approximately constant.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME057  
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WEPME059 Conceptual Design of a Storage Ring Vacuum System Compatible with Implementation of a Seven Bend Achromat Lattice at the APS radiation, storage-ring, photon, synchrotron 2409
 
  • B.K. Stillwell, B. Brajuskovic, H. Cease, D.L. Fallin, J. R. Noonan, M.M. O'Neill
    ANL, Argonne, Ilinois, USA
  
  A conceptual design is presented for a storage ring vacuum system at the Advanced Photon Source (APS) which is compatible with a multi-bend achromat (MBA) lattice under development for the APS Upgrade (APS-U) project [1]. Together, the interface with the magnets, required quantity and stability of beam position monitors, synchrotron radiation loading, and beam physics requirements place a demanding set of constraints on the vacuum system design. However, the requirements can be satisfied with a hybrid system which combines conventional extruded aluminum chambers incorporating “antechambers” with a variety of simpler tubular chambers made variously of copper-plated stainless steel, NEG-coated copper, and bare aluminum. This hybrid system has advantages over an all NEG-coated copper system with regard to overall project risk, required installation time, and maintainability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME059  
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WEPRI001 Clean Room Integration of the European XFEL Cavity Strings cavity, cryomodule, quadrupole, alignment 2474
 
  • S. Berry, O. Napoly, B. Visentin
    CEA/DSM/IRFU, France
  • F. Chastel, A. Clippet, M. Mbeleg, P. Pluvy
    ALSYOM, Argebteuil, France
  • C. Cloué, C. Madec, T. Trublet
    CEA/IRFU, Gif-sur-Yvette, France
  
  The 101 cryomodules of the XFEL cold linac will be integrated at Saclay under the CEA responsability by the industrial operator ALSYOM, at the production rate of cryomodule per week. Each cryomodule includes a string of 8 Niobium superconducting cavities and a BPM-quadripole unit (downstream end). To avoid particle contamination of the RF cavities, the strings are assembled in an ISO4 cleanroom by following strict cleaning and high-vacuum procedures. The major technical challenge of the string integration thus lies in the capacity to realize 25 connections in two weeks while protecting the cavity and coupler RF surfaces and to check their leak-tightness up to 10-10 hPA.l/s. The partial demonstration was made by the CEA team with the first pre-series module XM-3 which achieves a total accelerating voltage of 232 MV preserving the individual performances of cavities. In this paper the status and challenges of the production line is presented, including the quality management, equipment and operator training aspects. The optimisation process toward a faster assembly while preserving or actually decreasing the cavity exposure to contamination sources is also described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI001  
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WEPRI004 Operational Experience and Upgrades of the SOLEIL Storage Ring RF System cavity, operation, cryogenics, SRF 2480
 
  • P. Marchand, J.P. Baete, R.C. Cuoq, H.D. Dias, M. Diop, J.L. Labelle, R. Lopes, M. Louvet, C.M. Monnot, L.S. Nadolski, S. Petit, F. Ribeiro, T. Ruan, R. Sreedharan, K. Tavakoli
    SOLEIL, Gif-sur-Yvette, France
  
  In the SOLEIL storage ring, two cryomodules provide to the electron beam an accelerating voltage of 3-4 MV and a power of 575 kW at 352 MHz. Each cryomodule contains a pair of superconducting cavities, cooled with liquid Helium at 4.5 K, which is supplied by a single 350 W cryogenic plant. The RF power is provided by four solid state amplifiers, each delivering up to 180 kW. The parasitic impedances of the high order modes (HOM) are strongly mitigated by means of four coaxial couplers, located on the central pipe connecting the two cavities. Eight years of operational experience with this system, as well as its upgrades, are reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI004  
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WEPRI012 Euclid Modified SRF Conical Half-wave Resonator Design cavity, simulation, controls, operation 2502
 
  • E.N. Zaplatin
    FZJ, Jülich, Germany
  • T.L. Grimm, A. Rogacki
    Niowave, Inc., Lansing, Michigan, USA
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Funding: This Work is supported by the DOE SBIR Program, contract # DE-SC0006302.
The new low-beta conical Half-Wave Resonator (cHWR) is suggested for CW proton accelerators of new generation with relatively low beam loading, where frequency detune caused by microphonics and helium pressure fluctuations is essential. This particular design, considered in the paper, has operation frequency of 162.5 MHz, b=v/c=0.11, and is suitable for the first section of the PIP-II superconducting accelerator which is under development at Fermilab. The main idea of the cHWR design is to provide a self-compensation cavity design together with its helium vessel to minimize the resonant frequency dependence on external loads. A unique cavity side-tuning option is also under development. Niowave, Inc. proposed a series of cavity and helium vessel modifications to simplify their manufacturing. The whole set of numerical simulations has been generated to verify that the main parameters of the initial structure design were not affected by the proposed modifications. Here we present the main results of the cavity and helium vessel modified design. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI012  
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WEPRI018 Status of the Fabrication of the XFEL 3.9 GHz Cavity Series cavity, status, linac, gun 2512
 
  • C. Maiano, M. Bertucci, A. Bosotti, J.F. Chen, P. Michelato, L. Monaco, M. Moretti, C. Pagani, R. Paparella, P. Pierini, D. Sertore
    INFN/LASA, Segrate (MI), Italy
  
  The third harmonic system at 3.9 GHz of the European XFEL (E-XFEL) injector section will linearize the bunch RF curvature, induced by first accelerating module, before the first compression stage and it is a joint INFN and DESY contribution to the project. This paper presents the status of the fabrication of the 3.9 GHz cavity series in view of the XFEL injector commissioning in 2015.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI018  
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WEPRI022 In-house Production of a Large-Grain Single-Cell Cavity at Cavity Fabrication Facility and Results of Performance Tests cavity, accelerating-gradient, SRF, radio-frequency 2519
 
  • T. Kubo, Y. Ajima, H. Inoue, K. Umemori, Y. Watanabe, M. Yamanaka
    KEK, Ibaraki, Japan
  
  We studied electron beam welding (EBW) conditions for large grain Nb, and fabricated a single cell cavity in Cavity Fabrication Facility (CFF), KEK. Vertical-test results of the cavity made from large grain Nb are also presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI022  
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WEPRI023 Review of the Multilayer Coating Model experiment, factory, interface 2522
 
  • T. Kubo, T. Saeki
    KEK, Ibaraki, Japan
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto, Japan
  
  Structures of alternating layers of superconducting (Sc) and insulating films formed on a bulk Sc proposed by A. Gurevich in 2006 are actively discussed these years, because of their great possibility in reducing power consumptions and in enhancing RF breakdown field of the Sc RF cavity. On Apr. 2013, we submitted general formulae for the vortex penetration field of the Sc layer and the shielded magnetic field on the bulk Sc for a structure with a single Sc layer and a single insulator layer formed on a bulk Sc, by which a combination of the thicknesses of Sc and insulator layers that can realize the enhanced RF breakdown field can be found for any given materials. In this contribution, we will show progresses during the last year. Comparisons between the formulae and experimental results, and extended formulae for more realistic models, such as a model with surface defects, will be shown.
T. Kubo, Y. Iwashita, and T. Saeki, Appl. Phys. Lett. 104, 032603 (2014); arXiv:1304.6876 [physics.acc-ph]; arXiv:1306.4823 [physics.acc-ph]; arXiv:1307.0583 [physics.acc-ph].
 		 
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WEPRI032 First Cryomodule Test at AMTF Hall for The European X-ray Free Electron Laser (XFEL) cryomodule, free-electron-laser, cavity, laser 2546
 
  • K. Kasprzak, B. Dzieza, W. Gaj, D. Karolczyk, L.M. Kolwicz-Chodak, A. Kotarba, A. Krawczyk, K. Krzysik, W. Maciocha, A. Marendziak, K. Myalski, S. Myalski, T. Ostrowicz, B. Prochal, M. Sienkiewicz, M. Skiba, J. Świerbleski, M. Wiencek, J. Zbroja, P. Ziolkowski, A. Zwozniak
    IFJ-PAN, Kraków, Poland
  
  The Accelerator Module Test Facility (AMTF) at DESY in Hamburg is dedicated to the tests of RF cavities and accelerating cryomodules for the European X-ray Free Electron Laser (XFEL). The AMTF hall is equipped with two vertical cryostats, which are used for RF cavities testing and three test benches that will be used for tests of the accelerating cryomodules. Recently, the first cryomodule teststand (XATB3) was commissioned and the first XFEL cryomodule (XM-2) was tested by team of physicists, engineers and technicians from The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences in Kraków, Poland, as a part of Polish in-kind contribution to XFEL. This paper describes the preparation for the cryomodule test, differences with the old teststands CryoModule Test Bench (CMTB), the cryomodule test and the test procedure updates done at the AMTF test bench. The first test of the accelerating cryomodule on the AMTF was successfully performed and the preliminary test results are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI032  
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WEPRI036 Fabrication Design of QWR and HWR Cryomodules cryomodule, linac, cavity, cryogenics 2555
 
  • W.K. Kim, H. Kim, H.J. Kim, Y. Kim, M. Lee, G.-T. Park
    IBS, Daejeon, Republic of Korea
  
  The superconducting linac of RAON consists of five types of cryomodules. The cryomodules host QWR, HWR1, HWR2, SSR1, and SSR2 superconducting cavities. The cryomodules will be operated at 2K in order to test the performance of the superconducting cavities. The design of the cryomodule components is based on thermal shield to prevent incoming heat, two-phase pipe to supply superfluid helium, vacuum vessel for the formation of the internal vacuum, supporter parts for alignment and keeping structure, and magnetic shield to prevent external magnetic field. The detailed fabrication design of the cryomodules will be presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI036  
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WEPRI039 LIPAc SRF Linac Couplers Conditioning linac, SRF, operation, electron 2562
 
  • D. Regidor, I. Kirpitchev, J. Mollá, P. Méndez, M. Weber, C. de la Morena
    CIEMAT, Madrid, Spain
  • S. Chel, M. Desmons, G. Devanz, H. Jenhani
    CEA/IRFU, Gif-sur-Yvette, France
  • H. Dzitko
    CEA, Pontfaverger-Moronvilliers, France
  
  The LIPAc SRF Linac is a cryomodule with eight superconducting HWR cavities at 175 MHz powered by RF couplers capable of transmitting up to 200 kW in CW. To prepare the couplers for operation, cleaning and high power RF processing are needed. When performed, the couplers will be ready for integration in the cryomodule. The Couplers Test Bench has been designed to perform the RF conditioning by pairs, providing good matching, low losses and the required UHV level. To preserve the cleanliness of the internal surfaces, after the test bench manufacturing, an ISO5 clean room has been used for the vacuum parts assembly. The size and number of particles was carefully controlled during the assembly process. The RF conditioning was performed at the IFMIF-EVEDA RF Integration Facility using the Prototype RF Module in travelling wave and standing wave modes. The process started with short pulses at low power and finished when full power CW was reached. Vacuum, multipacting, arcs and matching were continuously monitored to control the process avoiding damages. An overview of the process applied to the prototypes and the RF conditioning results are presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI039  
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WEPRI059 Assembly and Installation of the UV Laser Delivery and Diagnostic Platform and the Photocathode Imaging System for the ASTA Front-end laser, optics, diagnostics, gun 2618
 
  • D.J. Crawford, R. Andrews, T.W. Hamerla, J. Ruan, J.K. Santucci, D. Snee
    Fermilab, Batavia, Illinois, USA
  
  Funding: This work was supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The Advanced Superconducting Test Accelerator (ASTA) is in the early stage of commissioning. The Front-End consists of a 1.5 cell normal conducting RF Gun resonating at 1.3 GHz with a gradient of up to 40 MV/m, a cesium telluride cathode for photoelectron production, a pulsed 264 nm ultra-violet (UV) laser delivery system, and a diagnostic area for measuring the characteristics of the photoelectron beam. We report on the design, construction, and early experience of the ultra-violet (UV) Laser Delivery and Diagnostic Platform and the Photocathode Imaging System. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI059  
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WEPRI061 Cornell's Main Linac Cryomodule for the Energy Recovery Linac Project linac, cavity, cryomodule, alignment 2624
 
  • R.G. Eichhorn, B. Bullock, J.V. Conway, B. Elmore, F. Furuta, Y. He, G.H. Hoffstaetter, J.J. Kaufman, M. Liepe, T.I. O'Connel, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Cornell University has been designing and building superconducting accelerators for various applications for more than 50 years. Currently, an energy-recovery linac (ERL) based synchrotron-light facility is proposed making use of the existing CESR facility. As part of the phase 1 R&D program funded by the NSF, critical challenges in the design were addressed, one of them being a full linac cryo-module. It houses 6 superconducting cavities- operated at 1.8 K in continuous wave (CW) mode - with individual HOM absorbers and one magnet/ BPM section. Pushing the limits, a high quality factor of the cavities (2•1010) and high beam currents (100 mA accelerated plus 100 mA decelerated) are targeted. We will present the status of the main linac cryomodule (MLC) fabrication and the findings on the cavity performance and component testing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI061  
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WEPRI063 Flux Trapping in Nitrogen-Doped and 120 C Baked Cavities cavity, SRF, linac, niobium 2631
 
  • D. Gonnella, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: United States Department of Energy
It is well known that external magnetic fields can cause higher residual resistance in superconducting RF cavities if the field is present during cooldown. However, the effect of cavity preparation and surface mean free path on the resulting residual resistance from magnetic field is less well studied. In this paper, we report on recent studies at Cornell in which two SRF cavities (one nitrogen-doped and one 120oC baked) were cooled through Tc in an applied uniform external magnetic field. Trapped flux and residual resistance were measured for a variety of cooldowns and applied magnetic fields. It was found that the residual resistance due to trapped flux in the nitrogen-doped cavity was three times larger than in the 120oC baked cavity. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI063  
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WEPRI064 New Insights into Heat Treatment of SRF Cavities in a Low-pressure Nitrogen Atmosphere cavity, niobium, SRF, resonance 2634
 
  • D. Gonnella, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: United States Department of Energy
Recent results from Cornell and FNAL have shown that superconducting RF cavities given a heat treatment in a nitrogen atmosphere of a few mTorr display an increase in Q0 with increasing accelerating field, opposite to the medium field Q slope usually observed. Three cavities was prepared at Cornell using this method and subsequently tested after different amounts of material removal. Cavity performance and material properties were extracted for each cavity and correlated with material removal. This has given new insights into how material properties and the anti-Q slope depend on cavity preparation. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI064  
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WEPRI067 Multi-Physics Analysis of CW Superconducting Cavity for the LCLS-II using ACE3P cavity, simulation, feedback, operation 2645
 
  • Z. Li, C. Adolphsen, O. Kononenko, T.O. Raubenheimer, C.H. Rivetta, M.C. Ross, L. Xiao
    SLAC, Menlo Park, California, USA
  
  Funding: Work was supported by the U.S. DOE contract DE-AC02-76SF00515 and used the resources of NERSC at LBNL under US DOE Contract No. DE-AC03-76SF00098.
The LCLS-II linac utilizes superconducting technology operating at continuous wave to accelerate the 1-MHz electron beams to 4 GeV to produce tunable FELs. The TESLA 9-cell superconducting cavity is adopted as the baseline design for the linac. The design gradient is approximately 16 MV/m. The highest operating current is 300 μA. Assuming that the RF power is matched at the highest current, the optimal loaded QL of the cavity is found to be around 4·107. Because of the high QL, the cavity bandwidth approaches the background microphonic detuning, and the performance of the cavity is tightly coupled to the mechanical perturbations of the cavity/cryomodule system. The resulting large phase and amplitude variations in the cavity require active feedback to achieve the 0.01% amplitude and phase stability requirements. To understand the cavity RF response and feedback requirements to the microphonics and Lorentz Force detuning, we have developed a simulation model of the RF-mechanical coupled system using parameters obtained with the multi-physics solver ACE3P. We will present the simulation results of the LCLS-II linac under different power feed scenarios and feedback schemes. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI067  
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WEPRI068 Conceptual Design of an Ideal Variable Coupler for Superconducting Radiofrequency 1.3 GHz Cavities cavity, scattering, Windows, coupling 2648
 
  • C. Xu, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  
  We present a new type of fundamental mode accelerator structure coupler. This coupler has a very simplified mechanical structure and is equipped with a novel vacuum window structure that allows the coupler to be divided into two parts. These two parts are fully thermally isolated, only coupled by thermal radiation. The rf power on the other hand get coupled perfectly from one part to the other. This is truly novel approach which is quite different than the conventional approach to this problem such as chock structure. The structure in general is slightly overmoded. We show that this structure can also be adopted to change the coupling coefficient and thus be tuned for an external Q. This could be of great utility for CW operation. We show the analytical and numerical calculation for a two window variable coupler.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI068  
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WEPRI069 Reproducibility of High-Q SRF Cavities by High Temperature Heat Treatment cavity, SRF, induction, niobium 2651
 
  • P. Dhakal, G. Ciovati, P. Kneisel, G.R. Myneni
    JLab, Newport News, Virginia, USA
  
  Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
Recent work on high-temperature (> 600 °C) heat treatment of ingot Nb cavities in a customized vacuum furnace for several hours showed the possibility of achieving Q0-values of up to ~5×1010 at 2.0 K, 1.5 GHz and accelerating gradients of ~20 MV/m. This contribution presents results on further studies of the heat treatment process to produce cavities with high Q0 values for continuous-wave accelerator application. Single-cell cavities of different Nb purity have been processed through few cycles of heat-treatments and chemical etching. Measurements of Q0 as a function of temperature at low RF field and of Q0 as a function of the RF field at or below 2.0 K have been made after each treatment. Measurements by TOF-SIMS of the impurities’ depth profiles were made on samples heat treated with the cavities. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI069  
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WEPRI085 The Elettra 3.5 T Superconducting Wiggler Refurbishment wiggler, electron, controls, storage-ring 2687
 
  • D. Zangrando, R. Bracco, D. Castronovo, M. Cautero, E. Karantzoulis, S. Krecic, G.L. Loda, D. Millo, L. Pivetta, G. Scalamera, R. Visintini
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • S.V. Khrushchev, N.A. Mezentsev, V.A. Shkaruba, V.M. Syrovatin, O.A. Tarasenko, V.M. Tsukanov, A.A. Volkov
    BINP SB RAS, Novosibirsk, Russia
  
  A 3.5 Tesla 64 mm period superconducting wiggler (SCW) was constructed by the Russian Budker Institute of Novosibirsk (BINP) and installed in the Elettra storage ring as a photon source for the second X-ray diffraction beamline in November 2002, but never used due to the lack of the funding required for the beamline construction. About three years ago, the beamline construction was finally funded together with the refurbishment of the SCW. This upgrade, that was necessary in order to make the SCW operations compatible with the top up mode of the storage ring aimed in a drastic reduction of the liquid helium consumption by means of replacing the cryostat with a new version. At the same time the upgrade aimed as well to improve the reliability of the cryostat, to update the control system and to verify the magnetic field performance after a very long time of inactivity. In this paper we present and discuss the performances of the SCW following its refurbishment carried out by BINP team and its re-commissioning in the Elettra storage ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI085  
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WEPRI091 Superconducting Multipole Wigglers: State of the Art wiggler, radiation, synchrotron, synchrotron-radiation 4103
 
  • N.A. Mezentsev, S.V. Khrushchev, V.K. Lev, V.A. Shkaruba, V.M. Syrovatin, V.M. Tsukanov
    BINP SB RAS, Novosibirsk, Russia
  
  Superconducting multipole wigglers installed on synchrotron radiation sources are the powerful tools for researches in various areas of science and technics. SuperConducting Multipole Wigglers (SCMWs) represent sign-alternating sequence of magnets with lateral magnetic field. Relativistic electrons, passing through such set of magnetic elements, create radiation with properties of synchrotron radiations depending on maximum field its period and poles number. The first superconducting wiggler has been made and installed on the VEPP-3 electron storage ring as generator of synchrotron radiation in 1979. Nowadays tens of wigglers are successfully working in the various synchrotron radiation centers and more than 10 of them were developed and made in Budker INP. These wigglers may be divided into 3 groups: 1- Short period 3-3.5 cm with field ~2-2.5 Tesla 2- Medium period 4.8-6 cm with field ~ 3.5-4.5 Tesla 3- Long period 14.5-20 cm with field 7-7.5Tesla. The description of magnetic properties of the wigglers, parameters of both cryogenic and vacuum systems and their technical decisions are presenteded in the report.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI091  
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WEPRI093 Welding and Quality Control for the Consolidation of the LHC Superconducting Magnets and Circuits controls, operation, superconducting-magnet, monitoring 2709
 
  • S. Atieh, M. Bernardini, F.F. Bertinelli, P. Cruikshank, J.M. Dalin, G. Favre, V. Kain, D. Lombard, A. Perin, M. Pojer, G. Rasul, D. Rey, R. Rizwan, F. Savary, J.Ph. G. L. Tock
    CERN, Geneva, Switzerland
  
  The first LHC long shutdown was driven by the need to consolidate the 13 kA splices between the superconducting magnets to safely attain its center of mass design energy of 14 TeV. Access to the splices requires the opening of welded sleeves by machining. After consolidation, the sleeves are re-welded using a TIG orbital welding. The welding process has been modified from the original “as-new” installation in order to better adapt to the “as repaired” situation. The intervention has been thoroughly prepared through qualifications, organisation of teams, their training and follow-up. Quality control is based on the qualification of equipment, process and operators; the recording of production parameters; regular process audits and production witness samples; visual inspection through an official certifying body. The paper also describes welding and quality control of special intervention cases, with issues of difficult access requiring innovative solutions. This work concerns over 10 000 welds and a team of 40 engineers and technicians over a period of 18 months. The experience and lessons learnt will be applicable to similar large complex projects.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI093  
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WEPRI105 Preliminary Design of Cooling System for a PrFeB-based Cryogenic Permanent Magnet Undulator Prototype at IHEP cryogenics, undulator, permanent-magnet, simulation 2743
 
  • Y.C. Zhang, S.P. Li, H.H. Lu, S.C. Sun, Y.F. Yang
    IHEP, Beijing, People's Republic of China
  
  A circulation cooling system is under progress for a 2-m-long PrFeB-based cryogenic permanent magnet undulator (CPMU) prototype at IHEP. Sub-cooled liquid nitrogen flows through each in-vacuum girder back and forth once. Refrigerant channels for both girders are parallel connected in vacuum chamber. Numerical simulation shows that the cooling system is able to cool down magnet array from 300 K to 83 K. Meanwhile, phase error increases about 0.1 degree.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI105  
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WEPRI106 Design of Cryomoudles for RAON cryomodule, cavity, linac, ion 2746
 
  • Y. Kim, C. Choi, H.M. Jang, Y.W. Jo, H.J. Kim, W.K. Kim, M. Lee
    IBS, Daejeon, Republic of Korea
  
  The accelerator will be built in Korea called RAON has four kinds of superconducting cavities such as QWR, HWR1, SSR1 and SSR2, and those cavities are operating in 2 K. The fabrication design for the SSR1 and SSR2 cryomodules are reported in this paper. The issues included in the paper are thermal and structural analysis results for the components such thermal shield, support post, two phase pipe, and so on.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI106  
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WEPRI110 The HNOSS Horizontal Cryostat and the Helium Liquefaction Plant at FREIA cavity, cryogenics, operation, linac 2759
 
  • R. Santiago Kern, T.J.C. Ekelöf, K.J. Gajewski, L. Hermansson, R.J.M.Y. Ruber, V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  • P. Bujard, N.R. Chevalier, T. Junquera, J.P. Thermeau
    Accelerators and Cryogenic Systems, Orsay, France
  
  A horizontal cryostat to test superconducting cavities and magnets at liquid helium temperatures is installed at FREIA (Facility for REsearch Instrumentation and Accelerator development) at Uppsala University, Sweden. The cryostat allows full testing of superconducting spoke and elliptical accelerating cavities without the need of a specialized cryomodule per cavity. Because horizontal cryostats are custom-built, their number in the accelerator world is very limited. The FREIA horizontal cryostat is one of a kind as it has been designed to be versatile: it is able to house either two ESS double-spoke, or two ESS/TESLA type elliptical cavities, or superconducting magnets or a combination of these with all the ancillary equipment (power couplers, tuners, etc) and test them at the same time, reducing installation time but requiring extra design effort and cryogens supply. In order to achieve this, a helium liquefier with a capacity of 140 l/h delivers liquid helium to the horizontal cryostat while the return gases are directed towards a recovery system, connected in closed loop with the liquefier.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI110  
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THXA01 BPMs From Design to Real Measurement electronics, simulation, cavity, operation 2774
 
  • D. Lipka, S. Vilcins
    DESY, Hamburg, Germany
  
  Beam Position Monitors (BPM) are an essential tool for the operation of an accelerator. Therefore BPM systems have to be already included from the beginning in the design of a new machine. This contribution describes the development of a new BPM system up to the operation with a focus on the mechanical design. It includes the collection of the requirements and boundary conditions which defines the kind of BPM system. Following the mechanical designing process is described where simulations are used to predict the signals. These results are input parameters for the design and optimization of the electronics. Several contributions are considered which can modify the BPM signal like feedhroughs, heating due to wake losses, holders, cables and so on. The steps from the design, the prototypes and series production including laboratory and test accelerator measurements up to the commissioning are described as well.  
slides icon Slides THXA01 [4.844 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THXA01  
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THOBB02 Superconducting Cavity Cryomodule Designs for the Next Generation of CW Linacs: Challenges and Options cavity, cryomodule, cryogenics, operation 2831
 
  • T.H. Nicol, Y.O. Orlov, T.J. Peterson, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Funding: Supported by FRA under DOE Contract DE-AC02-07CH11359
The designs of nearly all superconducting RF (SRF) linacs over the last several years, with one notable exception being CEBAF at Jefferson Lab, have assumed pulsed beam operation with relatively low duty factors. These include the XFEL at DESY, the ILC, the original configuration for Project X at Fermilab, as well as several others. Recently proposed projects, on the other hand, including the LCLS-II at SLAC, the newly configured low and medium energy sections for Project X, and FRIB at Michigan State, to name a few, assume continuous wave or CW operation on quite a large scale with ambitious gradients and cavity performance requirements. This has implications in the cavity design as well as in many parts of the overall cryomodule due to higher dynamic heat loads in the cavities themselves and higher heat loads in the input and high-order-mode (HOM) couplers. Piping internal to the cryomodule, the effectiveness of thermal intercepts, the size of integrated heat exchangers, and many other aspects of the overall design are also affected. This paper will describe some of these design considerations as we move toward the next generation of accelerator projects. 		 
slides icon Slides THOBB02 [8.388 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THOBB02  
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THOBB03 Novel Device for In-situ Thick Coatings of Long, Small Diameter Accelerator Vacuum Tubes cathode, electron, target, plasma 2834
 
  • A. Hershcovitch, M. Blaskiewicz, J.M. Brennan, W. Fischer, C.J. Liaw, W. Meng, R.J. Todd
    BNL, Upton, Long Island, New York, USA
  • A.X. Custer, A.A. Dingus, M.Y. Erickson, N.Z. Jamshidi, R.R. Laping, H.J. Poole
    PVI, Oxnard, California, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
To alleviate the problems of unacceptable ohmic heating and of electron clouds, a 50 cm long cathode magnetron mole was fabricated and successfully operated to copper coat an assembly containing a full-size stainless steel cold bore RHIC magnet tubing connected to two types of RHIC bellows, to which two additional RHIC tubing pipes were connected. To increase cathode lifetime, movable magnet package was developed, and thickest possible cathode was made, with rather challenging target to substrate distance of less than 1.5 cm. The magnetron is mounted on a carriage with spring loaded wheels that successfully crossed bellows and adjusted for variations in vacuum tube diameter, while keeping the magnetron centered. Electrical power and cooling water are fed through a motorized spool driven umbilical cabling system, which is enclosed in a flexible braided metal sleeve. Optimized process to ensure excellent adhesion was developed. Coating adhesion of 10 μm Cu surpassed all industrial tests; exceeded maximum capability of a 12 kg pull test fixture. Details of experimental setup for coating two types of bellows and a full-scale magnet tube sandwiched between them will be presented. 		 
slides icon Slides THOBB03 [2.033 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THOBB03  
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THPRO004 Study of the CLIO FEL in the Far-infrared in a Partially Guided Mode FEL, cavity, undulator, simulation 2859
 
  • J.-M. Ortega, J.P. Berthet, F. Glotin, R. Prazeres
    LCP/CLIO, Orsay, Cedex, France
  
  The infrared free-electron laser offers a large tunability since the FEL gain remains high throughout the infrared spectral range, and the reflectivity of metal mirrors remains also close to unity. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator. A solution is to use this chamber as a waveguide by adaptating the radius of curvature of the cavity mirrors to this regime. Then, as has been shown before* a minimum appears in the spectrum that can be produced by the FEL. We discuss the physical mechanism of this particular regime and compare it to experiments using vacuum chambers of different tranverse sizes. A good agreement is found with results of simulations and with a simple analytical formula.
* Analysis of the periodic power gaps observed in the tuning range of FELs with a partial waveguide, R. Prazeres, F. Glotin, J.-M. Ortega, Phys. Rev. STAB12, 010701 (2009)
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO004  
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THPRO012 Wakefield-based Dechirper Structures for ELBE wakefield, electron, radiation, controls 2882
 
  • F. Reimann, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  • U. Lehnert, P. Michel
    HZDR, Dresden, Germany
  
  Funding: Federal Ministry of Education and Research
The efficient reduction of the pulse length and the energy width of electron beams plays a crucial role in the generation of short pulses in the range of sub-picoseconds at future light sources. At the radiation source ELBE in Dresden Rossendorf short pulses are required for coherent THz generation and laser-electron beam interaction experiments such as X-ray Thomson scattering. Energy dechirping can be carried out passively by wakefields generated when the electron beam passes through suitable structures, namely corrugated and dielectrically lined cylindrical pipes or dielectrically lined rectangular waveguides (*,**,***). All structures offer the possibility to tune the resulting wakefield and therefore the resulting energy chirp through a variation of purely geometrical or material parameters. In this paper we present a semi-analytical approach to determine the wakefield in dielectrically lined rectangular waveguide, starting with the expression of the electric field in terms of the structure's eigenmodes.
* Bane, Stupakov, SLAC-PUB-14925 (2012)
** Mosnier, Novokhatski, in: Proceedings of PAC97, Vancouver, Canada, 1997
*** Antipov et al., in: Proceedings of IPAC2012, New Orleans, USA, 2012 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO012  
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THPRO024 Progress of the EU-XFEL Laser Heater laser, undulator, electron, photon 2912
 
  • M. Hamberg, V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  
  Funding: Swedish research council under Project number DNR-828-2008-1093 for financial support.
We describe the technical layout and report the status of the installation of the undulator, optical and vacuum systems of the laser heater for the EUXFEL. The laser heater is a device to increase the overall X-ray brightness stability. This is achieved by an optical laser system which induce an additional momentum spread in the electron bunches to reduce micro-bunching instabilities. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO024  
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THPRO044 Report on Gun Conditioning Activities at PITZ in 2013 gun, cathode, cavity, FEL 2962
 
  • M. Otevřel, P. Boonpornprasert, J.D. Good, M. Groß, I.I. Isaev, D.K. Kalantaryan, M. Khojoyan, G. Kourkafas, M. Krasilnikov, D. Malyutin, D. Melkumyan, T. Rublack, F. Stephan, G. Vashchenko
    DESY Zeuthen, Zeuthen, Germany
  • G. Asova
    INRNE, Sofia, Bulgaria
  • P. Boonpornprasert, S. Rimjaem
    Chiang Mai University, Chiang Mai, Thailand
  • F. Brinker, K. Flöttmann, S. Lederer, B. Marchetti, S. Schreiber
    DESY, Hamburg, Germany
  • Ye. Ivanisenko
    PSI, Villigen PSI, Switzerland
  • M.A. Nozdrin
    JINR, Dubna, Moscow Region, Russia
  • G. Pathak
    Uni HH, Hamburg, Germany
  • D. Richter
    BESSY GmbH, Berlin, Germany
  
  Recently three RF guns were prepared at the Photo Injector Test Facility at DESY, location Zeuthen (PITZ) for their subsequent operation at FLASH and the European XFEL. The gun 3.1 is a previous cavity design and is currently installed and operated at FLASH, the other two guns 4.3 and 4.4 were of the current cavity design and are dedicated to serve for the start-up of the European XFEL photo-injector. All three cavities had been dry-ice-cleaned prior their conditioning and hence showed low dark current levels. The lowest dark current level – as low as 60μA at 65MV/m field amplitude – has been observed for the gun 3.1. This paper reports in details about the conditioning process of the most recent gun 4.4. It informs about experience gained at PITZ during establishing of the RF conditioning procedure and provides a comparison with the other gun cavities in terms of the dark currents. It also summarizes the major setup upgrades, which have affected the conditioning processes of the cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO044  
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THPRO054 LLNL X-band Test Station Commissioning and X-ray Status gun, laser, alignment, emittance 2992
 
  • R.A. Marsh, G.G. Anderson, S.G. Anderson, C.P.J. Barty, M. Betts, S.E. Fisher, D.J. Gibson, F.V. Hartemann, S.S.Q. Wu
    LLNL, Livermore, California, USA
  
  Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344
An X-band test station is being commissioned at LLNL to support inverse Compton-scattering x-ray and gamma-ray source development. The X-band test station has been built and this presentation will focus on its current status and the generation of first electron beam. Special focus will be placed on the high gradient conditioning of the T53 traveling wave accelerator and Mark 1 X-band standing wave RF gun. Design and installation of the inverse-Compton scattering interaction region, future upgrade paths and configuration for a variety of x-ray and gamma-ray applications will be discussed along with the status of theory and modeling efforts. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO054  
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THPRO078 Time-dependent Behaviour of Gas Ejected from an Accelerating Structure after a Discharge distributed, injection, HOM, damping 3062
 
  • V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  
  Funding: This work is supported by the 7th European Framework program EuCARD under grant number 227579.
A discharge or RF-breakdown event in a CLIC acceleration structure causes the localized release of gas molecules inside a thin conduction limited system with distributed pumping. We discuss the transient behavior of such a system in the molecular flow regime that allows an analytical solution with the help of Greens functions. They describe the temporal evolution of the gas density and the gas flow ejected from the ends of thin pipes of finite length. Distributed pumping, for example through the HOM damping slits is taken into account. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO078  
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THPRO116 Control System of a Miniature 12 MeV Race-Track Microtron controls, operation, detector, microtron 3165
 
  • Yu.A. Kubyshin, V. Blasco, J.A. Romero, A. Sanchez
    UPC, Barcelona, Spain
  • G. Montoro
    UPC-EETAC-TSC, Castelldefels, Spain
  • V.I. Shvedunov
    MSU, Moscow, Russia
  
  A simple control system has been developed for the commissioning of a compact 12 MeV race-track microtron which is under construction at the Technical University of Catalonia. It is of modular structure and is based on LabView programs at a conventional PC and ATmega microcontrollers. Apart from modules to monitor different RTM systems it also includes an Automatic Frequency Control of the magnetron frequency and interlocks. The architecture and main features of the modules are described and results of their operation are reported. Further developments of the control system and interfaces are on the way.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO116  
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THPRO118 A PLC Test Bench at ESS PLC, EPICS, controls, timing 3171
 
  • D.P. Piso, M. Reščič
    ESS, Lund, Sweden
  • G. Cijan
    Cosylab, Ljubljana, Slovenia
  • R. Schmidt
    CERN, Geneva, Switzerland
  
  The European Spallation Source (ESS) is an accelerator- driven neutron spallation source. The Integrated Controls Systems (ICS) is responsible for providing control and mon- itoring for all parts of the machine (accelerator, target, neu- tron scattering systems and conventional facilities) [1]. A large number of applications have been identified across all parts of the facility where PLCs will be used: cryogenics, vacuum, water-cooling, power systems, safety and protec- tion systems. The Controls Division at ESS is deploying a PLC Test Bench. The motivation is to evaluate different technologies, to test PLCs and their integration into EPICS, to prototype control systems and use the test bench as PLC software development platform. This report defines the ar- chitecture of this infrastructure. The first stage to procure a first set of hardware and to perform initial tests has already been finished, consisting of a comparison between the per- formance of the s7plc EPICS driver and the Modbus EPICS driver. The results of these tests are discussed and future plans for this infrastructure are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO118  
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THPRO126 Implementation of Machine Protection System for the Taiwan Photon Source PLC, EPICS, status, controls 3189
 
  • C.Y. Liao, J. Chen, Y.-S. Cheng, K.T. Hsu, K.H. Hu, D. Lee, C.Y. Wu
    NSRRC, Hsinchu, Taiwan
  
  The Taiwan Photon Source (TPS) is being constructed at the campus of the NSRRC (National Synchrotron Radiation Research Center) and commissioning expected in 2014. In order to prevent damage to accelerator components induced by various events, a global machine protection system (MPS) was installed and implemented. The MPS collect interlocks and beam dump requests from various system (thermo/flow of magnets, front-end, vacuum system, and orbit excursion interlock), perform decision, transmit dump beam request to E-Gun or RF system. The PLC based system with embedded EPICS IOC was used as a slow MPS which can delivery less than 8 msec reaction time. The fast MPS was dependent on event based timing system to deliver response time less than 5 μs. Trigger signal for post-mortem will also be distributed by the fast MPS. To ensure alive of the system, several self-diagnostics mechanisms include heartbeat and transient capture were implemented and tested. The MPS architecture, installation, and validation test results were presented in this report.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO126  
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THPME035 High-performance Accelerating Cryomodule for the LINCE Project cryomodule, solenoid, radiation, shielding 3298
 
  • D. Gordo-Yáñez, R. Carrasco Dominguez, I. Martel, A.R. Pinto Gómez
    University of Huelva, Huelva, Spain
  • C. Gómez
    IDOM, Bilbao, Spain
  
  Funding: Work partially supported by the Spanish Government (MINECO-CDTI) under program FEDER INTERCONNECTA.
The linear accelerator of LINCE consists on 26 superconducting quarter-wave resonators with three different geometric betas working at 72.75 and 109.125 MHz and three types of SC solenoids. In this paper we discuss the first cryomodule design based on thermal and mechanical studies carried out in COMSOL Multiphysics. This includes the design of cavity and solenoid cryostats, liquid-helium reservoir and layout of the cryogenic tank. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME035  
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THPME063 Residual Dose with 400 MeV Injection Energy at J-PARC Rapid Cycling Synchrotron injection, operation, linac, synchrotron 3379
 
  • K. Yamamoto, N. Hayashi, M. Kinsho
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  Last summer shutdown J-PARC RCS injection energy was upgraded from 181 MeV to 400 MeV. We report the effect of the injection energy upgrade on the residual dose in the RCS.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME063  
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THPME064 Progress and Status of the J-PARC 3GeV RCS injection, operation, linac, power-supply 3382
 
  • M. Kinsho
    JAEA/J-PARC, Tokai-mura, Japan
  
  Big issue for the J-PARC 3GeV RCS was displacement of main magnets caused by last big earthquake because this made beam loss more than 400 kW beam power. Since realignment of main magnet and other components was essential to realize higher beam power and stable operation, this work has been done last maintenance period. To minimize amount of realignment work, we decided that not all components moved to designed regular potions but also minimum components moved to the position which was secured design acceptance 486 π mm mrad. Almost all components which are main magnets, rf cavities, and extraction magnets had to be moved in the range of 10 mm for horizontal, 3 mm for vertical and 9 mm for longitudinal, respectively. It was not necessary for the components installed in injection straight line to move because displacement of these components was less than ± 0.2 mm. At same time 400 MeV injection upgrade work should be done. Beam commissioning is planned from the middle of January 2014. The progress and status of the RCS in J-PARC are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME064  
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THPME077 Complex Beam Profile Reconstruction, A Novel Rotating Array of Vibrating Wires operation, extraction, instrumentation, detector 3415
 
  • S.G. Arutunian
    ANSL, Yerevan, Armenia
  • J.R. Alonso
    LBNL, Berkeley, California, USA
  
  Proton/ion beams of multiple charge/mass ratio can be very complex. Orthogonal X-Y projections are often inappropriate to represent these profiles. An array of vibrating wires, rotating around the beam axis is under development. The mechanical implementation is described. An algorithm to reconstruct the profile is proposed. The tradeoffs between the number of wires, the rotation angles, the response time and the profile resolution are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME077  
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THPME083 BPM Data Correction at SOLEIL electronics, synchrotron, storage-ring, experiment 3430
 
  • N. Hubert, B. Béranger, L.S. Nadolski
    SOLEIL, Gif-sur-Yvette, France
  
  In a synchrotron light source like SOLEIL, Beam Position Monitors (BPM) are optimized to have the highest sensitivity for an electron beam passing nearby their mechanical center. Nevertheless, this optimization is done to the detriment of the response linearity when the beam is off-centered for dedicated machine physic studies. To correct for the geometric non-linearity of the BPM, we have applied an algorithm using boundary element method. Moreover the BPM electronics is able to provide position data at a turn-by-turn rate. Unfortunately the filtering process in this electronics mixes the information from one turn to the neighboring turns. An additional demixing algorithm has been set-up to correct for this artefact. The paper reports on performance and limitations of those two algorithms that are used at SOLEIL to correct the BPM data.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME083  
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THPME086 Optical Fiber Beam Loss Monitor for the PHIL and ThomX Facilities beam-losses, radiation, photon, operation 3433
 
  • I. Chaikovska, L. Burmistrov, N. Delerue, A. Variola
    LAL, Orsay, France
  
  Fiber beam loss monitor (FBLM) is an attractive solution to measure intensity and position of the beam losses in the real time. It is a very useful tool, especially, for the commissioning and beam alignment. In this article we report on the development of the FBLM at PHIL (PHotoinjector at LAL, Orsay, France) as a prototype of the beam loss monitor for the ThomX machine, the compact Compton based X-ray source being in the construction phase in Orsay.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME086  
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THPME092 Status of Diamond Detector Development for Beam Halo Investigation at ATF2 electron, detector, photon, cathode 3449
 
  • S. Liu, P. Bambade, F. Bogard, J-N. Cayla, H. Monard, C. Sylvia, T. Vinatier
    LAL, Orsay, France
  • N. Fuster-Martínez
    IFIC, Valencia, Spain
  • I. Khvastunov
    National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine
  • T. Tauchi, N. Terunuma
    KEK, Ibaraki, Japan
  
  Funding: Chinese Scholarship Council
We are developing a diamond detector for beam halo and Compton spectrum diagnostics after the interaction point (IP) of ATF2, a low energy (1.3 GeV) prototype of the final focus system for ILC and CLIC linear collider projects. Tests of a 500 μm thick sCVD diamond detector with a dimension of 4.5 mm×4.5 mm have been carried out with radioactive sources and with electron beam from PHIL low energy (<10 MeV) photo-injector at LAL. The tests at PHIL were done with different beam intensities in air, just after the exit window at the end of the beam line, to test the response of the diamond detector and the readout electronics. We have successfully detected signals from single electrons, using a 40 dB amplifier, and from an electron beam of 108 electrons, using a 24 dB attenuator. A diamond sensor with 4 strips has been designed and fabricated for installation in the vacuum chambers of ATF2 and PHIL, with the aim to scan both the beam halo (with 2 strips of 1.5 mm×4 mm) and the beam core (with 2 strips of 0.1 mm×4 mm) transverse distributions. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME092  
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THPME094 Measurement of Low-charged Electron Beam with a scintillator Screen detector, electron, diagnostics, laser 3456
 
  • T. Vinatier, P. Bambade, C. Bruni, S. Liu
    LAL, Orsay, France
  
  Measuring electron beam charge lower than 1pC is very challenging since the traditional diagnostics, like Faraday Cup and ICT, are limited in resolution to a few pC. A way to simply measure lower charge would be to use the linear relation, existing before saturation regime, between the incident charge and the total light intensity emitted by a YAG screen. Measurement has been performed on PHIL accelerator at LAL, with charge lower than 50pC, with a YAG screen located just in front of a Faraday Cup. It shows a very good linear response of the YAG screen up to the Faraday Cup resolution limit (2pC) and therefore allows calibrating the YAG screen for lower charge measurement with an estimated precision of 4%. A noise analysis allows estimating the YAG screen resolution limit around 40fC. Results of low charge measurement on PHIL will be shown and compared to those coming from a diamond detector installed on PHIL, in order to validate the measurement principle and to determine its precision and resolution limit. Such simple measurement may thereafter be used as single-shot charge diagnostic for electron beam generated and accelerated by laser-plasma interaction.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME094  
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THPME098 Set up of a Synchrotron Light Monitor at the 2.5 GeV Booster Synchrotron at ELSA synchrotron, radiation, diagnostics, injection 3468
 
  • T. Schiffer
    Uni Bonn, Bonn, Germany
  • P. Hänisch, W. Hillert, M.T. Switka
    ELSA, Bonn, Germany
  
  For the upgrade of the accelerator facility ELSA towards higher stored beam currents, a non-destructive beam analysis is being implemented at the 2.5 GeV booster synchrotron. It is a fast ramping combined function synchrotron with an extraction repetition rate of 50 Hz. Typically, beam currents of 10 mA are accelerated from 20 MeV to the extraction energy of 1.2 GeV within 8.6 ms, hence the magnetic field is increased by up to 85 T/s. A synchrotron light monitor as the primary diagnostic tool will be utilized for measuring the transversal position and intensity distribution of the beam. Its dynamics on the fast energy ramp is of distinct interest. The proposed set-up of the synchrotron light monitor and the current development are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME098  
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THPME126 General Consideration for Button-BPM Design booster, storage-ring, synchrotron, GUI 3537
 
  • A.R. Molaee, M.Sh. Shafiee
    ILSF, Tehran, Iran
  • M. Mohammadzadeh
    Shahid Beheshti University, Evin, Tehran, Iran
  • M. Samadfam
    Sharif University of Technology (SUT), Tehran, Iran
  
  In order to design Button Beam Position Monitors (BPMs) for synchrotron facilities, one algorithm by C# have been developed which can calculate all required parameters to analyze optimal design based on vacuum chamber and button dimensions. Beam position monitors are required to get beam stabilities on submicron levels. For this purpose, different parameters such as capacitance, sensitivity versus bandwidth, intrinsic resolution, induced charge and voltage on buttons are calculated. Less intrinsic resolution and high sensitivity and capacitance are desired. To calculate induced charge and voltage on each button, Poisson's equation has been solved by Green method. For sensitivities calibration, two-dimensional map of BPM response is obtained theoretically and compared with the CST simulation map. Results show a good agreement where as their difference is less than 5%.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME126  
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THPME134 Experimental Results of a Gas Jet Based Beam Profile Monitor electron, ion, alignment, storage-ring 3559
 
  • V. Tzoganis
    RIKEN Nishina Center, Wako, Japan
  • A. Jeff, V. Tzoganis, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • A. Jeff, V. Tzoganis, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Jeff
    CERN, Geneva, Switzerland
  
  Funding: Work supported by the EU under grant agreement 215080, HGF and GSI under contract number VH-NG-328, the STFC Cockcroft Institute Core Grant Mo.ST/G008248/1, and a RIKEN-Liverpool studentship.
A novel, least invasive beam profile monitor based on a supersonic gas jet has been developed by the QUASAR Group at the Cockcroft Institute, UK. It allows the measurement of beam profiles for various particle beams across a range of energies and vacuum levels to be made. A finely collimated neutral gas jet, produced by a nozzle and several skimmers, is injected into a vacuum chamber perpendicular to the main particle beam. Ionization by the primary beam produces ions which are extracted from the interaction region and directed towards an imaging detector. This contribution presents the design of the monitor and first experimental results obtained with a low energy electron beam. It also discusses solutions of previous alignment problems and challenges in the realization of a versatile control and data acquisition system 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME134  
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THPME151 New Station for Optical Observation of Electron Beam Parameters at Electron Storage Ring SIBERIA-2 electron, storage-ring, diagnostics, controls 3611
 
  • Stirin, A.I. Stirin, V. Korchuganov, G.A. Kovachev, D.G. Odintsov, Yu.F. Tarasov, A.V. Zabelin
    NRC, Moscow, Russia
  • V.L. Dorohov, A.D. Khilchenko, A.L. Scheglov, L.M. Schegolev, A.N. Zhuravlev, E.I. Zinin
    BINP SB RAS, Novosibirsk, Russia
  
  The paper is dedicated to a new station for optical observation of electron beam parameters which was built at the synchrotron radiation (SR) storage ring SIBERIA-2 at Kurchatov Institute. The station serves for the automatic measurement of electron bunches transverse and longitudinal sizes with the use of SR visible spectrum in one-bunch and multi-bunch modes; the study of individual electron bunches behaviour in time with changing different accelerator parameters, the precise measurement of betatron and synchrotron oscillations frequency. The station with its diagnostic systems on the optical table is located outside the shielding wall of the storage ring. The paper contains an outline scheme of SR beam line and a block-scheme of optical measurement part, describes the principle of operation and technical characteristics of main system elements (dissector tube, 16-element avalanche photodiode array, CCD-matrix, etc.) as well as results of electron beam optical diagnostics and an estimation of accuracy of the bunches parameters measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME151  
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THPME152 Application of the Optical Diagnostics during the Commissioning of the Booster of NSLS-II booster, diagnostics, synchrotron, radiation 3614
 
  • O.I. Meshkov, S.M. Gurov
    BINP SB RAS, Novosibirsk, Russia
  • V.V. Smaluk
    DLS, Oxfordshire, United Kingdom
  • X. Yang
    BNL, Upton, Long Island, New York, USA
  
  We describe the experience obtained with several types of diagnostics during commissioning of the booster of NSLS-II. The set includes fluorescent screens, synchrotron light monitors and beam loss monitors. The information that was useful for commissioning as well as advantages and disadvantages of each diagnostics are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME152  
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THPME156 Convergent Cherenkov Radiation from Dielectric Targets target, radiation, optics, FEL 3626
 
  • S.N. Galyamin, E.S. Belonogaya, A.V. Tyukhtin, V.V. Vorobev
    Saint-Petersburg State University, Saint-Petersburg, Russia
  • E.S. Belonogaya
    LETI, Saint-Petersburg, Russia
  
  Funding: Work was supported by the Grant of the President of Russian Federation (No. 273.2013.2).
Cherenkov radiation is a convenient tool for charged particle detection and bunch diagnostics. However, due to the complexity of real radiator geometry, different approximate techniques are elaborated for investigation of excited radiation*. Here we develop recently reported** approximate method for calculating Cherenkov radiation of a charge flying near a dielectric target having two main boundaries (the first interacts with a charge field and the second mainly refracts a generated radiation). We focus on cases where the radiation outside the target is convergent and use two methods for field investigation: ray optical technique and aperture integration technique. First, we deal with the case of a conical target with a vacuum channel. Under certain conditions, this radiation is concentrated near the line being the symmetry axis of the target. Second, we find the specific shape of the target that concentrates radiation in a small vicinity of given point (focus). Such targets can be used for improvement of detectors and bunch diagnostics systems based on Cherenkov effect.
*A.P. Potylitsyn et al., Diffraction Radiation from Relativistic Particles, STMP 239 (Springer, 2010).
**E.S. Belonogaya, A.V. Tyukhtin, S.N. Galyamin, Phys. Rev. E, 87, 043201 (2013).
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME156  
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THPME157 Radiation of a Charged Particle Bunch Moving in the Presence of Planar Wire Structure radiation, diagnostics, electronics, operation 3629
 
  • V.V. Vorobev, S.N. Galyamin, A.V. Tyukhtin
    Saint-Petersburg State University, Saint-Petersburg, Russia
  
  Funding: Work was supported by "Dynasty" Foundation, the Grant of the President of Russian Federation (No. 273.2013.2) and the Russian Foundation for Basic Research (Grant No. 12-02-31258).
The structure under consideration represents a set of long thin parallel wires which are placed in a plane with fixed spacing. The wires can exhibit a limited conductivity. If the period of the structure is much less than the typical wavelength, the structure’s influence can be described with help of the averaged boundary conditions*. The main attention is given to the case when the bunch flies through the grid in the orthogonal direction. Radiation of charged particle bunch which have small transversal size and limited longitudinal one is studied. Analytical expressions for volume and surface waves are given for the bunches with arbitrary longitudinal profile. A separate analysis is performed for the particular case of the plane which is ideally conducting in only one direction. It is shown that the surface wave is similar, in some way, to the radiation field of the bunch moving in a wire metamaterial**. It is demonstrated that the detection of surface waves can be used to estimate the longitudinal sizes of bunches. Typical numerical results for bunches of different shapes and structures with different parameters are given.
* M.I. Kontorovich et al, Electrodynamics of Grid Structures (Moscow, 1987).
** V.V. Vorobev, A.V. Tyukhtin, Phys. Rev. Let., 108, 184801 (2012).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME157  
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THPME171 General-purpose Spectrometer for Vacuum Breakdown Diagnostics for the 12 GHz Test Stand at CERN electron, simulation, klystron, diagnostics 3668
 
  • M. Jacewicz, Ch. Borgmann, J. Ögren, R.J.M.Y. Ruber, V.G. Ziemann
    Uppsala University, Uppsala, Sweden
  
  Funding: This work is supported by the grants from the the Swedish Research Council DNR-2011-6305 and DNR-2009-6234.
We discuss a spectrometer to analyze the electrons and ions ejected from a high-gradient CLIC accelerating structure that is installed in the klystron-driven 12 GHz test-stand at CERN. The charged particles escaping the structure provide useful information about the physics of the vacuum breakdown within a single RF pulse. The spectrometer consists of a dipole magnet, a pepper-pot collimator, a fluorescent screen and a fast camera. This enables us to detect both transverse parameters such as the emittance and longitudinal parameters such as the energy distribution of the ejected beams. We can correlate these measurements with e.g. the location of the breakdown inside the structure, by using information from the measured RF powers, giving in that way a complete picture of the vacuum breakdown phenomenon. The spectrometer was installed during Spring 2014 and will be commissioned during Summer 2014. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME171  
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THPME182 Precise Instruments for Bunch Charge Measurement pick-up, resonance, impedance, monitoring 3703
 
  • A. Kalinin
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  For the pulse charge q injected into a capacitor of a parallel resonating circuit, the oscillation voltage V on a series resistor R is V=qwRexp(—wt/2Q)sin(wt–1/2Q), t>τ, where w is the resonance frequency, Q>>1 is the quality factor and τ<<1/w is the pulse length. Of the two main parameters, R is known, and w can be found directly from the signal above. The quality factor contribution is low, and its rough estimation is sufficient to retain voltage accuracy. The observations above open a possibility of precise bunch charge measurement. We describe a bunch charge monitor that is a cavity with a lump capacitor as a low impedance coaxial line connected to a gap in the vacuum pipe. An LC electronic circuit is also presented. It integrates the single bunch current delivered by a Faraday Cup, or a Wall Current Monitor, or a Fast Current Transformer. The circuit has w~30MHz, Q~20, and with a Faraday Cup, the lower range is 10pC/V and the noise floor is about 20fC. Several such circuits are in use on the VELA injector in Daresbury Laboratory.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME182  
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THPME188 Using Principal Component Analysis to Find Correlations and Patterns at Diamond Light Source electron, storage-ring, data-analysis 3719
 
  • C. Bloomer, G. Rehm
    DLS, Oxfordshire, United Kingdom
  
  Principal component analysis is a powerful data analysis tool, capable of reducing large complex data sets containing many variables. Examination of the principal components set allows the user to spot underlying trends and patterns that might otherwise be masked in a very large volume of data, or hidden in noise. Diamond Light Source archives many gigabytes of machine data every day, far more than any one human could effectively search through for correlations. Presented in this paper are some of the results from running principal component analysis on years of archived data in order to find underlying correlations that may otherwise have gone unnoticed. The advantages and limitations of the technique are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME188  
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THPRI002 DAΦNE General Consolidation and Upgrade controls, detector, linac, quadrupole 3760
 
  • C. Milardi, D. Alesini, S. Bini, B. Buonomo, S. Cantarella, A. De Santis, G.O. Delle Monache, G. Di Pirro, A. Drago, L.G. Foggetta, O. Frasciello, A. Gallo, A. Ghigo, F. Iungo, C. Ligi, L. Pellegrino, R. Ricci, U. Rotundo, C. Sanelli, G. Sensolini, A. Stecchi, A. Stella, M. Zobov
    INFN/LNF, Frascati (Roma), Italy
  • R. Gargana, A. Michelotti
    Consorzio Laboratorio Nicola Cabibbo, Frascati, Italy
  
  In the first six months of 2013 the KLOE detector has been upgraded inserting new detector layers in the inner part of the apparatus, around the interaction region. The long shutdown has been used to undertake a general consolidation program aimed at improving the Φ-Factory operation stability and reliability and, in turn, the collider uptime. In this context several systems have been revised and upgraded, new diagnostic elements have been installed, some critical components have been modified and the interaction region mechanical support structure design has been developed to improve its mechanical stability and to deal with the weight added by the new detector layers.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI002  
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THPRI005 The Mechanical and Vibration Studies of the Final Focus Magnet-cryostat for SuperKEKB ground-motion, interaction-region, quadrupole, superconducting-magnet 3770
 
  • H. Yamaoka, Y. Arimoto, K. Kanazawa, M. Masuzawa, Y. Ohsawa, N. Ohuchi, K. Tsuchiya, Z.G. Zong
    KEK, Ibaraki, Japan
  
  Construction of the SuperKEKB has been progressed in KEK. The target luminosity of the SuperKEKB is 8×1035 cm-2s−1, which is 40 times larger than the KEKB. The vertical beam sizes of electron and positron must be squeezed to the level of 50 nano-meter at the interaction point. The beam final focus system for the SuperKEKB consists of 4-superconducting (SC) quadrupole doublets, 43 SC-correctors, 4 SC-compensation solenoids. The designs of the cryostats in the left and right side with respect to the beam interaction point are being studied with the progress of the magnet designs. In the design works, the support structure of each cryostat, strength of the cryostat components and support rods for supporting cold mass are investigated. As for the vibration issue, vibration properties of the superconducting quadrupole magnets due to the ground motion has been studied. Also vibration properties of the concrete bridges where the two cryostats will be placed in the interaction region were investigated and measured. We will present the cryostat designs and these vibration studies in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI005  
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THPRI016 Pulse Based Data Archive System and Analysis for Current and Beam Loss Monitors in the J-PARC RCS linac, injection, ion-source, ion 3800
 
  • N. Hayashi, S. Hatakeyama, K. Yamamoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  The data archive system in the J-PARC 25-Hz Rapid-Cycling Synchrotron (RCS) records the beam intensity and the beam loss monitor (BLM) pattern for all pulses. The system is based on the common memory and utilizes the timing system of the J-PARC. Although its time resolution is limited, it is useful to detect rare events or phenomena appearing with only higher accelerator repetition. Using these data, the stability of the beam intensity, particularly ion source can be examined. The relation between BLM patterns and its causes can be studied pulse-by-pulse basis and it would make use of future improvements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI016  
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THPRI019 Reliability and Availability Modeling for Accelerator Driven Facilities software, simulation, operation, linac 3803
 
  • O. Rey Orozko, E. Bargalló, A. Nordt
    ESS, Lund, Sweden
  • A. Apollonio, R. Schmidt
    CERN, Geneva, Switzerland
  
  Accelerator driven facilities are and will have to be designed to a very high level of reliability and beam availability to meet expectations of the users and experiments. In order to fulfill these demanding requirements on reliability and overall beam availability, statistical models have been developed. We compare different statistical reliability models as well as tools in terms of their performance, capacity and user-friendliness. In addition we also benchmarked some of the existing models. We will present in detail a tool being used for LHC and LINAC4 which is based on the commercially available software package Isograph and a tool using Excel, which was developed in house for ESS-systems. The impact of an early reliability modeling on the design of mission critical systems will be presented as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI019  
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THPRI027 Automated Conditioning System for Siemens Novel Electrostatic Accelerator software, power-supply, interface, controls 3825
 
  • H. von Jagwitz-Biegnitz
    JAI, Oxford, United Kingdom
  • P. Beasley, O. Heid, T. Kluge
    Siemens AG, Erlangen, Germany
  • D.C. Faircloth
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • R.G. Selway
    Inspired Engineering Ltd, Climping, United Kingdom
  
  Siemens has proposed a novel compact DC electrostatic tandem accelerator to produce protons of a few MeV and is currently commissioning a prototype at the Rutherford Appleton Laboratory. The geometry of the accelerator involves large surfaces which are exposed to high electric fields and therefore need long procedures for conditioning. An automated system for conditioning has been developed. It reacts quicker to breakdowns than a human operator could do, thus being more effective and also reduces the time spent by research staff on the conditioning.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI027  
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THPRI028 Acoustic Spark Localization for the 201 MHz RF Cavity cavity, experiment, Windows, software 3828
 
  • P.G. Lane, Y. Torun
    Illinois Institute of Technology, Chicago, Illinois, USA
  • E. Behnke, I.Y. Levine
    Indiana University South Bend, South Bend, USA
  • D.W. Peterson
    Fermilab, Batavia, Illinois, USA
  • P. Snopok
    IIT, Chicago, Illinois, USA
  
  Funding: Work supported by U.S. Department of Energy
Current designs for muon cooling channels require high-gradient RF cavities to be placed in solenoidal magnetic fields in order to contain muons with large transverse emittances. It has been found that doing so reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields it would be helpful to have a diagnostic tool which can detect breakdown and localize the source of the breakdown inside the cavity. We report here on the experiment setup for localizing sparks in an RF cavity by using piezoelectric transducers and on preparation for data collection on a 201.25 MHz vacuum cavity. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI028  
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THPRI042 Design and RF Test of Damped C-Band Accelerating Structures for the ELI-NP Linac HOM, damping, operation, linac 3856
 
  • D. Alesini, S. Bini, R. D. Di Raddo, V.L. Lollo, L. Pellegrino
    INFN/LNF, Frascati (Roma), Italy
  • L. Ficcadenti, V. Pettinacci
    INFN-Roma, Roma, Italy
  • L. Palumbo
    URLS, Rome, Italy
  • L. Serafini
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  
  The linac energy booster of the European ELI-NP proposal foresees the use of 12 traveling wave C-Band structures, 1.8 m long with a field phase advance per cell of 2pi/3 and a repetition rate of 100 Hz. Because of the multi-bunch operation, the structures have been designed with a damping of the HOM dipoles modes in order to avoid beam break-up (BBU). They are quasi-constant gradient structures with symmetric inputs couplers and a strong damping of the HOM in each cell. An optimization of the electromagnetic and mechanical design has been done to simplify the fabrication and to reduce their cost. In the paper we shortly review the whole design criteria and we illustrate the low and high power RF test results on prototypes that shown the feasibility of the structure realization and the effectiveness of the HOM damping.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI042  
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THPRI044 Vacuum Waveguide System for SPring-8 Linac Injector Section linac, electron, klystron, operation 3863
 
  • T. Taniuchi, H. Dewa, H. Hanaki, T. Kobayashi, T. Magome, A. Mizuno, S. Suzuki, K. Yanagida
    JASRI/SPring-8, Hyogo-ken, Japan
  
  An SF6 waveguide system for the injector section of SPring-8 linac has been replaced in a vacuum waveguide system including a newly developed vacuum circulator and an isolator. This paper describes developed RF components, a waveguide configuration and an RF conditioning of the system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI044  
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THPRI045 Development of a 1.3-GHz Buncher Cavity for the Compact ERL cavity, operation, simulation, gun 3866
 
  • T. Takahashi, Y. Honda, T. Miura, T. Miyajima, H. Sakai, S. Sakanaka, K. Shinoe, T. Uchiyama, K. Umemori, M. Yamamoto
    KEK, Ibaraki, Japan
  
  In a high-brightness injector of the Compact ERL (cERL), a 1.3-GHz buncher cavity is used to compress the electron bunches which are produced at a 500-kV photocathode DC electron gun. An rf voltage required is about 130 kV. To elongate the lifetime of the photocathode of the DC gun which is located beside the buncher cavity, an extremely-low pressure of about 10-9 Pa is required in the buncher cavity under operating conditions. In order to achieve such low pressures, we have developed a normal-conducting cavity which included several measures to reduce the outgas from the cavity components, together with careful rf designs to avoid any problems due to multipactor discharges or to other problems. With the developed cavity, we achieved a vacuum pressure of about 2·10-9 Pa under rf operations at an rf voltage of about 100 kV. The buncher cavity was installed in the cERL, and it worked very well; we could demonstrate to compress the bunch length from 10 ps (FWHM) to 0.5 ps (rms) using the buncher cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI045  
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THPRI050 Calculation and Design of the Re-buncher Cavities for the LIPAc Deuteron Accelerator cavity, pick-up, operation, beam-transport 3881
 
  • D. Gavela, I. Podadera, F. Toral
    CIEMAT, Madrid, Spain
  
  Funding: This work has been partially funded by the Spanish Ministry of Economy and Competitiveness under project AIC-A-2011-0654
Two re-buncher cavities are necessary for the LIPAc (Linear IFMIF Prototype Accelerator), presently being built at Rokkasho (Japan). They are placed at the Medium Energy Beam Transport (MEBT) line to longitudinally focus a 5 MeV CW deuteron beam. Due to the strong space charge and the compactness of the beamline, the cavity has several space restrictions. In order to minimize the power loss, an IH-type cavity with 5 gaps was selected. It provides an effective voltage of 350 kV at 175 MHz with a power loss of 6.6 kW. First, electromagnetic calculations have been done with HFSS to compute the resonant frequency, the S-parameters, the electric and magnetic field maps, the power losses and the proper geometry for a magnetic input coupler and a pickup probe. Then, a mechanical Ansys model has been used to analyze the stresses and deformations due to vacuum, the cooling circuit and the temperature distribution, taking into account the power losses imported from the electromagnetic model. Finally, the fluid dynamics in the cooling circuits of the stems has been carefully studied. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI050  
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THPRI051 Fabrication and Tests of the Re-buncher Cavities for the LIPAc Deuteron Accelerator cavity, pick-up, coupling, simulation 3884
 
  • D. Gavela, P. Abramian, J. Calero, A. Guirao, J.L. Gutiérrez, E. Molina Marinas, I. Podadera, L. Sánchez, F. Toral
    CIEMAT, Madrid, Spain
  
  Funding: This work has been partially funded by the Spanish Ministry of Economy and Competitiveness under project AIC-A-2011-0654
Two re-buncher cavities will be installed at the Medium Energy Beam Transport (MEBT) of the LIPAc accelerator, presently being built at Rokkasho (Japan). They are IH-type cavities with 5 gaps and will provide an effective voltage of 350 kV at 175 MHz. The cavity consists of a cylindrical main body and two endplates in stainless steel with an internal copper coating. The stems and drift tubes are machined from bulk OFE copper. The fabrication techniques for the cooling pipes, the input coupler and the pick-up are presented. Material choices and fabrication process are discussed. The first re-buncher is already fabricated. RF low power tests have been made to measure resonant frequency, S-parameters and Q-factor before and after the copper plating. The electric field map has also been measured with the bead-pull method. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI051  
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THPRI052 Design, Fabrication and Tests of the Second Prototype of the Double-Length CLIC PETS alignment, collider, RF-structure, acceleration 3887
 
  • L. Sánchez, J. Calero, D. Gavela, J.L. Gutiérrez, F. Toral
    CIEMAT, Madrid, Spain
  • D. Gudkov, G. Riddone
    CERN, Geneva, Switzerland
  
  Funding: This work has been partially funded by the Spanish Ministry of Economy and Competitiveness under project FPA2010-21456-C02-02
The future collider CLIC is based on a two-beam acceleration scheme, where the drive beam provides to the main beam the RF power through the Power Extraction and Transfer Structures (PETS). The technical feasibility of some components is currently being proved at the CLIC Experimental Area (CLEX). Two double- length CLIC PETS will be installed in CLEX to validate their performance with beam. The first prototype was produced and validated in 2012. This paper is focused on the engineering design, fabrication and validation of the second prototype. Taking into account the results of the first prototype, some modifications have been included in the design to ease fabrication and assembly. The fabrication techniques are very similar to the ones used for the first prototype. Mechanical measurements on single parts and different assembly stages will be reported. The industrialization feasibility will be also analyzed. Finally, several tests such as vacuum tightness and RF measurements with low power have been realized to validate the device. These results are compared with the first prototype ones. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI052  
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THPRI056 A New Debunching Cavity for the ISIS H− Injector cavity, simulation, DTL, radio-frequency 3899
 
  • B.S. Drumm, A.P. Letchford, R.E. Williamson
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • M. Keelan
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  
  The energy range of the ISIS 70MeV H− injected beam is reduced using an RF debunching cavity. The existing cavity consists of a mild steel vacuum vessel containing a water-cooled copper shell into which RF power is fed. The unit is made up of components designed for the 50 MeV Proton Linear Accelerator (PLA) which used to occupy the Rutherford Appleton Laboratory (RAL) site between 1957 and 1969. The component drawings date back to the late 1960s. Due to its age, complexity and a lack of spares, there is a need for a modern solution. This paper documents the development of a new debunching cavity for the ISIS neutron source.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI056  
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THPRI060 Conceptual Design of an Electromagnetic Driven Undulator Based Positron Target System for ILC target, gun, positron, photon 3908
 
  • W. Gai, W. Liu
    ANL, Argonne, Illinois, USA
  
  There have been intense activities on development of the fast spinning Ti wheel positron target for ILC in the last few years. As in many high power target design, it requires solutions for many technical challenges, such as vacuum, thermal stress and radiation damage control, just to name a few. Due to the unique beam timing structure, in this paper, we present a target system based on a electromagnetic mechanical system that drives a bullet type Ti slug (~ 1.4x1.4x10 cm, weigh ~ 50 g) as the target system. The mechanism is similar to a reloadable EM rail gun driven projectiles. The system can be compact, vacuum isolated, and ease of cooling. Conceptual design layout and parameter estimations are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI060  
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THPRI066 Design of a 1.3 GHz Two-cell Buncher for APEX cavity, HOM, impedance, dipole 3924
 
  • H.J. Qian, K.M. Baptiste, J.A. Doyle, D. Filippetto, S. Kwiatkowski, C. F. Papadopoulos, D. Patino, F. Sannibale, J.W. Staples, S.P. Virostek, R.P. Wells
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
The design of a 1.3 GHz buncher cavity for the APEX project, a MHz repetition rate high-brightness photoinjector, is presented. The buncher cavity operates at 240 kV in CW mode, and it compresses the 750 keV beam from APEX gun through ballistic compression. Compared with a single cell design, a two-cell cavity doubles the shunt impedance to 7.8 MΩ, which greatly relaxes the requirements for both RF amplifier and cavity cooling. Coupler design, multipacting analysis, HOM analysis and thermal analysis will be presented in this paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI066  
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THPRI070 Tuner System Simulation and Tests for the 201-MHz MICE Cavity cavity, simulation, controls, feedback 3927
 
  • L. Somaschini
    INFN-Pisa, Pisa, Italy
  • A.J. DeMello, A.R. Lambert, S.P. Virostek
    LBNL, Berkeley, California, USA
  • J.H. Gaynier, R.J. Pasquinelli, D.W. Peterson, R.P. Schultz
    Fermilab, Batavia, Illinois, USA
  • Y. Torun
    Illinois Institute of Technology, Chicago, Illlinois, USA
  
  Funding: Supported by the US Department of Energy Office of Science through the Muon Accelerator Program.
The frequency of MICE cavities is controlled by pneumatic tuners as their operation is impervious to large magnetic fields. The mechanical and RF transfer functions of the tuner were simulated in ANSYS. The first of these tuning systems was assembled and tested at Fermilab. The mechanical response and the RF tuning transfer function have been measured and compared with simulation results. Finally the failure of different actuators has been simulated and tested to predict the operational limits of the tuner. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI070  
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THPRI071 Instrumentation for Characterizing 201-MHz MICE Cavity at Fermilab cavity, pick-up, instrumentation, electron 3930
 
  • M. Chung, D.L. Bowring, A. Moretti, R.J. Pasquinelli, D.W. Peterson, R.P. Schultz
    Fermilab, Batavia, Illinois, USA
  • P.G. Lane, Y. Torun
    Illinois Institute of Technology, Chicago, Illinois, USA
  • L. Somaschini
    INFN-Pisa, Pisa, Italy
  
  A 201-MHz single cavity module is installed in the Mucool Test Area (MTA) of Fermilab to test the performance of the cavity at the design parameters for the International Muon Ionization Cooling Experiment (MICE) particularly in multi-Tesla external magnetic fields. To monitor various aspects of the cavity and to understand detailed physics involved in RF breakdown and multipacting, numerous instrumentation is installed on the cavity module and also in the experimental hall, which includes thermocouples, infrared sensors, electron pickups, fiber light guides, and radiation detectors. In this paper, we will present details of each diagnostic and initial test results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI071  
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THPRI078 Experimental Study of Surface RF Magnetic Field Enhancement Caused by Closely Spaced Protrusions cavity, klystron, superconductivity, experiment 3949
 
  • F.Y. Wang, C. Adolphsen, J.P. Eichner, C.D. Nantista, L. Xiao
    SLAC, Menlo Park, California, USA
  
  The RF magnetic field enhancement between two closely spaced protrusions on a metallic surface has been studied theoretically. It is found that a large enhancement occurs when the field is perpendicular to the gap between the protrusions. This mechanism could help explain the melting that has been observed on cavity surfaces subjected to pulsed heating that would nominally be well below the melting temperature of the surface material. To test this possibility, an experiment was carried out in which a pair of copper “pins” was attached to the base plate of an X-band cavity normally used to study pulsed heating. Melting was observed between the pins when the predicted peak temperature was near or exceeded the copper melting temperature.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI078  
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THPRI091 Machine Protection Considerations for BERLinPro electron, linac, laser, diagnostics 3985
 
  • S. Wesch, M. Abo-Bakr, M. Dirsat, G. Klemz, P. Kuske, A. Neumann, J. Rahn, T. Schneegans
    HZB, Berlin, Germany
  
  Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
The Berlin energy-recovery-linac project BERLinPro at the HZB is a 50 MeV ERL test facility, which addresses physical and technological questions for future superconducting rf based high brightness, high current electron beam sources. The combination of a 100 mA cw beam, electron bunches with normalized emittances lower than 1 mm mrad and the magnet optics of BERLinPro leads to power densities capable to harm the accelerator components within microseconds if total beam loss occurs. Furthermore, continuous beam loss on the level of 10-5 has to be controlled to avoid activation and to protect the SRF, beam diagnostics and other infrastructure components. In this paper, we present the evaluation of the required key parameters of the BERLinPro machine protection system and present its first conceptual design. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI091  
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THPRI096 Use of Silicon Carbide as Beam Intercepting Device Material: Tests, Issues and Numerical Simulations radiation, interface, injection, booster 3998
 
  • C. Maglioni, M. Delonca, M. Gil Costa, A. Vacca
    CERN, Geneva, Switzerland
  
  Silicon Carbide (SiC) stands as one of the most promising ceramic material with respect to its thermal shock resistance and mechanical strengths. It has hence been considered as candidate material for the development of higher performance beam intercepting devices at CERN. Its brazing with a metal counterpart has been tested and characterized by means of microstructural and ultrasound techniques. Despite the very positive results, its use has to be evaluated with care, due to the strong evidence in literature of large and permanent volumetric expansion, called swelling, under the effect of neutron and ion irradiation. This may cause premature and sudden failure of components, and can be mitigated to some extent by operating at high temperature. For this reason limited information is available for irradiation below 100°C, which is the typical temperature reached in intercepting devices like dumps or collimators. This paper describes the brazing campaign carried out at CERN, the results, and the theoretical and numerical approach used to characterize the extent of the swelling phenomenon with radiation, as well as the p+ irradiation test program to be conducted in the next future.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI096  
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THPRI098 Brazing and Helium Leaking Test for High Heat Load Components in the Taiwan Photon Source photon, synchrotron, synchrotron-radiation, radiation 4004
 
  • P.A. Lin, C.K. Kuan, T.Y. Lee, H.Y. Lin, I.C. Sheng
    NSRRC, Hsinchu, Taiwan
  
  Taiwan Photon Source is the second accelerator constructed by National Synchrotron Radiation Research Center (NSRRC). With 3GeV, 500mA, this facility will generate extremely high synchrotron radiation and most of the power load will be shadowed at front end in order to shape final confining beam size for beam lines users. The high heat load components are known to be the critical parts to absorb the unwanted energy. In order to practically distribute high density power along each high heat load components, several absorbers are introduced. Namely, primary mask, main mask, photon absorber and slits. The manufacturing process such as UHV chemical cleaning, brazing and helium leaking test will be described in this report.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI098  
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THPRI103 Improvement of the Run-time of 35 mbar Helium Gas Pumping Units for the Superconducting Linear Accelerator S-DALINAC operation, coupling, controls, experiment 4019
 
  • J. Conrad, F. Hug, T. Kürzeder, N. Pietralla
    TU Darmstadt, Darmstadt, Germany
  
  Funding: Work supported by DFG through SFB 634
The superconducting Darmstadt linear accelerator S-DALINAC has been designed to provide electron beams of up to 130 MeV for nuclear and astrophysical experiments. The accelerating cavities are operated in a liquid helium bath at 2 K. To achieve this temperature the cryostat has to be pumped down to a pressure of 35 mbar which was done by a system of pumping units connected in series, when the accelerator started its operation in 1991. In 2005 this system was replaced by four parallel switched pumping stations. In the first three years of their operation, the reliability of the accelerator was very poor due to repeated breakdowns of the pumping stations caused by overheating. In addition the high temperatures lead to an early decay of the gaskets used. The problem was solved by installing oil cooling systems and more appropriate shaft sleeves at the pumping stations. We will report on the technical efforts we made and thereby further increased the availability of the accelerator significantly. Also we will give a review on our experiences in maintenance procedures. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI103  
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THPRI104 Design and Fabrication of Bunch Compressor Support System for PAL XFEL dipole, diagnostics, quadrupole, electron 4022
 
  • H.-G. Lee, Y.-G. Jung, H.-S. Kang, D.E. Kim, K.W. Kim, S.B. Lee, D.H. Na, B.G. Oh, K.-H. Park, H.S. Suh
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  Pohang Accelerator Laboratory(PAL) is developing a SASE X-ray Free Electron Laser based on 10 GeV linear accelerator. Bunch compressor support systems are developed to be used for the linear accelerator tunnel. The support system design is based on an asymmetric four-dipole magnet chicane in which asymmetry and variable R56. can be optimized. This flexibility is achieved by allowing the middle two dipole magnets to move transversely. Moving system consist of servo motor, rodless ball screw actuator and linear encoder. In this paper, we describe the design of the stages used for precise movement of the bunch compressor magnets and associated diagnostics components.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI104  
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THPRI106 Specialized Technical Services at ESS cryomodule, cryogenics, target, neutron 4028
 
  • J.G. Weisend, P. Arnold, J. Fydrych, W. Hees, G. Hulla, F. Jensen, J.M. Jurns, P. Ladd, G. Lanfranco, H. Spoelstra, X. Wang
    ESS, Lund, Sweden
  
  The European Spallation Source (ESS), a world class lab for neutron science currently under construction in Lund, Sweden requires a number of technical services that extend across the various project areas (accelerator, target and neutron science). These services include: cryogenics, vacuum and technical electrical and cooling systems. This effort constitutes more than 70 million Euros of construction cost. Rather than have separate support groups in each of the project areas, ESS has created a Specialized Technical Services group within the Accelerator Division to provide these services. This approach permits standardization, development of synergies and improved communication. The STS group also provides cryomodule testing and accelerator infrastructure and installation to the accelerator project. This paper describes the scope of work, current design status and future plans for Specialized Technical services at ESS.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI106  
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THPRI112 Basic Research on RF Absorbing Ceramics for Beam Line HOM Absorbers HOM, damping, higher-order-mode, linac 4040
 
  • R.G. Eichhorn, P. Quigley, V.D. Shemelin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • M. Carty
    Alfred University, Alfred, New York, USA
  • J. Matteson, A. Rae
    NanoMaterials Innovation Center LLC, Painted Post, USA
  
  Higher Order Mode (HOM) absorbers for future high current machines have been a challenging component for many years. Even though many different materials are commercially, none of them seems to fully qualify for accelerator applications. Some of them are brittle or chippy, others porous, have small bandwidth of absorption, a high dc resistivity leading to charge-up or are unreliable in terms of batch to batch variations. Alfred University and Cornell University have recently partnered in developing a dedicated absorber ceramic material that tries to overcome these limitations. We will report on results from small samples of different compositions we produced based on SiC, graphene and graphite.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI112  
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THPRI114 Apparatus and Technique for Measuring Low RF Resistivity of Tube Coatings at Cryogenic Temperatures cryogenics, electron, cavity, network 4046
 
  • A. Hershcovitch, M. Blaskiewicz, J.M. Brennan, J. Brodowski, W. Fischer, R. Than, J.E. Tuozzolo
    BNL, Upton, Long Island, New York, USA
  • A.X. Custer, A.A. Dingus, M.Y. Erickson, N.Z. Jamshidi, H.J. Poole
    PVI, Oxnard, California, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An in-situ technique for coating stainless steel vacuum tubes with Cu was developed to mitigate the problems of wall resistivity that leads to unacceptable ohmic heating of superconducting magnets cold bore and electron cloud generation in RHIC that can limit future machine luminosity enhancement. Room temperature RF resistivity of 10 μm Cu coated stainless steel RHIC beam tube has conductivity close to copper tubing. Before coating the RHIC beam pipe with copper, it is imperative to test the Cu coating’s conductivity at cryogenic. A folded quarter wave resonator structure has been designed and built for insertion in a cryogenic system to measure RF resistivity of copper coated RHIC tubing at liquid helium temperatures. The design is based on making the resonator structure out of a superconducting material such that the copper coating is the most lossy material. RHIC tubing samples prepared with different magnetron sputtering deposition modes are to be optimized by iterative processes. Additionally, this device can also be used for the development of better, cheaper SRF cavities and electron guns. The apparatus and its design details will be presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRI114  
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