Keyword: SRF
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MOYBP01 State-of-the-Art and Future Prospects in RF Superconductivity cavity, niobium, electron, storage-ring 11
 
  • K. Saito
    KEK, Ibaraki, Japan
  
  This presentation should recount the remarkable progress in improving the performance of superconducting cavities over the past 50 years and explore future directions, including advances in materials other than Nb, such as MgB2 and novel multi-layer superconductor-insulator systems. This talk should provide an overview of international activities.  
slides icon Slides MOYBP01 [10.097 MB]  
 
MOOAC02 Status and Plans for a Superconducting RF Accelerator Test Facility at Fermilab cryomodule, electron, cryogenics, gun 58
 
  • J.R. Leibfritz, R. Andrews, C.M. Baffes, K. Carlson, B. Chase, M.D. Church, E.R. Harms, A.L. Klebaner, M.J. Kucera, A. Martinez, S. Nagaitsev, L.E. Nobrega, J. Reid, M. Wendt, S.J. Wesseln
    Fermilab, Batavia, USA
  • P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  
  Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The Advanced Superconducting Test Acccelerator (ASTA) is being constructed at Fermilab. The existing New Muon Lab (NML) building is being converted for this facility. The accelerator will consist of an electron gun, injector, beam acceleration section consisting of 3 TTF-type or ILC-type cryomodules, multiple downstream beamlines for testing diagnostics and conducting various beam tests, and a high power beam dump. When completed, it is envisioned that this facility will initially be capable of generating a 750 MeV electron beam with ILC beam intensity. An expansion of this facility was recently completed that will provide the capability to upgrade the accelerator to a total beam energy of 1.5 GeV. Two new buildings were also constructed adjacent to the ASTA facility to house a new cryogenic plant and multiple superconducting RF (SRF) cryomodule test stands. In addition to testing accelerator components, this facility will be used to test RF power systems, instrumentation, and control systems for future SRF accelerators such as the ILC and Project-X. This paper describes the current status and overall plans for this facility. 		 
slides icon Slides MOOAC02 [13.423 MB]  
 
MOOAC03 Superconducting Resonators Development for the FRIB and ReA Linacs at MSU: Recent Achievements and Future Goals linac, cavity, cryomodule, ion 61
 
  • A. Facco
    INFN/LNL, Legnaro (PD), Italy
  • E.C. Bernard, J. Binkowski, C. Compton, J.L. Crisp, L.J. Dubbs, K. Elliott, A. Facco, L.L. Harle, M. Hodek, M.J. Johnson, D. Leitner, M. Leitner, I.M. Malloch, S.J. Miller, R. Oweiss, J. Popielarski, L. Popielarski, K. Saito, J. Wei, J. Wlodarczak, Y. Xu, Y. Zhang, Z. Zheng
    FRIB, East Lansing, Michigan, USA
  • A. Burrill, G.K. Davis, K. Macha, A.V. Reilly
    JLAB, Newport News, Virginia, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The superconducting driver and post-accelerator linacs of the FRIB project, the large scale radioactive beam facility under construction at MSU, require the construction of about 400 low-beta Quarter-wave (QWR) and Half-wave resonators (HWR) with four different optimum velocities. 1st and 2nd generation prototypes of β=0.041 and 0.085 QWRs and β=0.53 HWRs have been built and tested, and have more than fulfilled the FRIB and ReA design goals. The present cavity surface preparation at MSU allowed production of low-beta cavities nearly free from field emission. The first two cryostats of β=0.041 QWRs are now in operation in the ReA3 linac. A 3rd generation design of the FRIB resonators allowed to further improve the cavity parameters, reducing the peak magnetic field in operation and increasing the possible operation gradient , with consequent reduction of the number of required resonators. The construction of the cavities for FRIB, which includes three phases for each cavity type (development, pre-production and production runs) has started. Cavity design, construction, treatment and performance will be described and discussed.
Michigan State University designs and establishes FRIB as a DOE Office of Science National User Facility in support of the mission of the Office of Nuclear Physics. 		 
slides icon Slides MOOAC03 [4.009 MB]  
 
MOPPC096 Multiphysics Applications of ACE3P simulation, HOM, vacuum, cavity 361
 
  • K.H. Lee, C. Ko, Z. Li, C.-K. Ng, L. Xiao
    SLAC, Menlo Park, California, USA
  • G. Cheng, H. Wang
    JLAB, Newport News, Virginia, USA
  
  Funding: Work supported by US DOE Offices of HEP, ASCR and BES under contract AC02-76SF00515.
The TEM3P module of ACE3P, a parallel finite-element electromagnetic code suite from SLAC, focuses on the multiphysics simulation capabilities, including thermal and mechanical analysis for accelerator applications. In this pa- per, thermal analysis of coupler feedthroughs to supercon- ducting rf (SRF) cavities will be presented. For the realistic simulation, internal boundary condition is implemented to capture RF heating effects on the surface shared by a di- electric and a conductor. The multiphysics simulation with TEM3P matched the measurement within 0.4%. 		 
 
MOPPP015 Status of the BERLinPro Energy Recovery Linac Project cavity, linac, booster, quadrupole 601
 
  • J. Knobloch, M. Abo-Bakr, W. Anders, R. Barday, K.B. Bürkmann-Gehrlein, V. Dürr, S.C. Heßler, A. Jankowiak, T. Kamps, O. Kugeler, B.C. Kuske, P. Kuske, A.N. Matveenko, G. Meyer, R. Müller, A. Neumann, K. Ott, Y. Petenev, D. Pflückhahn, T. Quast, J. Rahn, S.G. Schubert
    HZB, Berlin, Germany
  
  Funding: Funding provided by the BMBF and the State of Berlin
In October 2010 Helmholtz Zentrum Berlin received funding to design and build the Berlin Energy Recovery Linac Project BERLinPro. The goal of this compact ERL is to develop the accelerator physics and technology required to generate and accelerate a 100-mA, 1 mm·mrad emittance beam. Given the flexibility of ERLs, other operation modes such as short-bunch operation will also be investigated. The BERLinPro technology and know-how can then be transferred to a variety of ERL-based applications. Presently, BERLinPro is in the design phase and the optics has been settled. Furthermore, first beam has been achieved with a superconducting RF photoinjector, which represents an important step towards realizing a CW injector for BERLinPro. An overview of the present status and the conceptual design report is presented. 		 
 
MOPPP028 SRF Photoinjector for Proof-of-principle Experiment of Coherent Electron Cooling at RHIC electron, gun, emittance, FEL 622
 
  • D. Kayran, S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, X. Liang, G.T. McIntyre, I. Pinayev, B. Sheehy, J. Skaritka, T. Srinivasan-Rao, R. Than, J.E. Tuozzolo, Q. Wu, T. Xin
    BNL, Upton, Long Island, New York, USA
  • V. Litvinenko, M. Ruiz-Osés
    Stony Brook University, Stony Brook, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy and by Stony Brook DOE grant DE-SC0005713.
Coherent Electron Cooling (CEC) based on FEL amplifier promises to be a very good way to cool protons and ions at high energies. A proof of principle experiment to demonstrate cooling at 40 GeV/u is under construction at BNL. One of possible sources to provide sufficient quality electron beam for this experiment is a SRF photoinjector. In this paper we discuss design and simulated performance of the photoinjector based on existing 112 MHz SRF gun and newly designed single-cavity SRF linac operating at 704 MHz. 		 
 
MOPPP047 Characterization of the First SRF Electron Beam Source at the Naval Postgraduate School cavity, cathode, electron, coupling 667
 
  • A.D. Holmes, A.B. Baxter, C.W. Bennett, J.R. Harris, J.W. Lewellen, R. Swent
    NPS, Monterey, California, USA
  • J.M. Didoszak, J.M. Utschig
    ONR, Arlington, Virginia, USA
  
  In June 2011, the Naval Postgraduate school (NPS) received the 500 MHz Mark I quarter-wave superconducting RF (SRF) electron beam source and, among other firsts, completed the first cool down and characterization of an SRF beam source at a US Naval facility. The Mark I has a photocathode with adjustable position and uses a unique cascaded RF coupler design. As part of an on-going advanced electron source development project, the NPS Beam Physics Laboratory (BPL) team continues characterization of the Mark I cavity at various cathode stalk, coupler, and probe positions. Methods and experimentation used to measure the cavity Q and β, as well as characteristic results, with respect to coupler, cathode stalk, and probe positions are presented.  
 
MOPPR016 Femtosecond Level Electron Bunch Diagnostic at Quasi – CW SRF Accelerators: Test Facility ELBE electron, diagnostics, laser, photon 810
 
  • M. Gensch, C. Kaya, U. Lehnert, P. Michel, Ch. Schneider, W. Seidel
    HZDR, Dresden, Germany
  • G. Geloni
    European XFEL GmbH, Hamburg, Germany
  • M. Helm
    FZD, Dresden, Germany
  • H. Schlarb, A. Shemmary, N. Stojanovic
    DESY, Hamburg, Germany
  
  Funding: BMBF through the PIDID proposal and HGF through the ARD initiative
At the srf based prototype cw accelerator ELBE a new electron beamline, providing for femtosecond electron bunches with nC bunch charges and repetition rates in the 1 – 200 KHz regime and with pC bunch charge and repetition rates of 13 MHz is currently constructed. The 40 MeV electrons will be used in photon-electron interaction experiments with TW and PW class laser and the generation of broad band and narrow bandwidth coherent THz pulses. In this paper we outline ideas for novel online diagnostics of the electron bunch properties (e.g. arrival time and bunch form) based on the time and frequency domain analysis of the emitted coherent THz radiation but also based on direct measurements by e.g. electro-optic sampling. The suitability of ELBE as a testbed for diagnostic of future cw X-ray photon sources (e.g. energy recovery linacs) will be discussed. 		 
 
TUEPPB005 Novel Technique of Suppressing TBBU in High-energy ERLs linac, HOM, lattice, electron 1122
 
  • V. Litvinenko
    BNL, Upton, Long Island, New York, USA
  
  Energy recovery linacs (ERLs) is emerging generation of accelerators promising revolutionize the fields of high-energy physics and photon sciences. One potential weakness of these devices is transverse beam-breakup instability, which may severely limit available beam current. In this paper I am presenting novel idea of using natural chromaticity in ERL arcs to suppressing TBBU instabilities. I present the theory of the process and two exact cases demonstrating that the threshold of TBBU instability could be raised by my orders of magnitude using this method.
* V.N. Litvinenko, Chromaticity of the lattice and beam stability in energy recovery linacs, submitted to PR ST-AB 		 
 
TUPPC065 High Intensity Beam Analysis for the Superconducting Radio-frequency Linac (SRF-Linac) of the IFMIF-EVEDA Accelerators emittance, resonance, linac, space-charge 1323
 
  • W. Simeoni
    CEA/IRFU, Gif-sur-Yvette, France
  • N. Chauvin, P.A.P. Nghiem, D. Uriot
    CEA/DSM/IRFU, France
  
  In this proceeding we analyze space charge effects on the beam dynamics of IFMIF accelerators. The objective is to be able to characterize and understand the crucial issues like halo formation, emittance growth and sudden particle losses in the SRF-Linac. We use the Hofmann stability charts to identify modes of collective space charge density oscillations that are responsible for the transfer and growth of the emittance. With identification of modes we are able to treat the parametric resonance between the modes and the nonlinear motion of an individual ion the amplitude of which is greater than the core radius. The resulting phase space consists of an inner separatrix containing the core and an outer separatrix that becomes the locus near which the halo particles enter and cluster.  
 
TUPPD054 Research Activities on Photocathodes for HZDR SRF Gun gun, cathode, vacuum, electron 1524
 
  • R. Xiang
    FZD, Dresden, Germany
  • A. Arnold, M. Freitag, P. Michel, P. Murcek, J. Teichert
    HZDR, Dresden, Germany
  
  Funding: We acknowledge the support of the European Community-Research Infrastructure Activity (EuCARD, contract number 227579), as well German Federal Ministry of Education and Research grant 05 ES4BR1/8.
Since 2005 the photocathode laboratory has been in operation at HZDR. The main goal is to prepare Cs2Te photocathodes for the SRF gun. A vacuum transport system with UHV is used to move the cathodes from preparation lab to accelerator hall. Up to now 31 Cs2Te photocathodes have been deposited and eight of them have been used in the SRF gun. Quantum efficiency of 1% and lifetime of months can be maintained during the gun operation. At the same time activities are directed towards new photocathode materials with high Q.E. for high current electron sources. Cs3Sb and GaN(Cs) photocathodes have been tested as new candidates, and the design of a preparation system for GaAs(Cs, O) is ongoing. 		 
 
TUPPD078 A Novel Design of a High Brightness Superconducting RF Photoinjector Gun Cavity gun, cavity, cathode, emittance 1581
 
  • F. Marhauser, R. Rodriguez
    MuPlus, Inc., Newport News, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported under U.S. DOE Grant Application Number 98802B12-I
Next generation electron accelerators for research, medical, defense or industrial use are in need of electron sources operating at high repetition rates of 1 MHz and beyond, with normalized emittance of 1 mm-mrad or less and bunch charges as much as one nC or more. A conceptual layout of a novel superconducting RF photoinjector gun cavity (SRF gun) is proposed, which can provide unprecedented flexibility to vary beam pulse patterns in the MHz regime and beyond at average currents around 1 mA. It does not require an opening in the center of the back wall and avoids the complex cathode exchange system, but still allows an exchange or refurbishment of the cathode. The demountable back plate has the major benefit to clean the cavity cells independently from the back wall carrying a superconductive photocathode. This mitigates risks of cavity contamination and eases fabrication and chemical post-processing to achieve high accelerating fields, a key parameter to guarantee high brightness beams. 		 
 
TUPPR045 Multi-cell VEP Results: High Voltage, High Q, and Localized Temperature Analysis cavity, radiation, controls, monitoring 1918
 
  • F. Furuta, B. Elmore
    Cornell University, Ithaca, New York, USA
  • A.C. Crawford
    Fermilab, Batavia, USA
  • G.M. Ge, G.H. Hoffstaetter, M. Liepe
    CLASSE, Ithaca, New York, USA
  
  We are developing Vertical Electro Polishing (VEP) system for niobium superconducting RF cavity at Cornell University. VEP has been successfully applied on different cell shapes (TESLA and Re-entrant), and single and multi-cell cavities. VEP achieved high gradient of 39MV/m with TESLA shape single cell and of 36MV/m with TESLA shape 9-cell, respectively. Preliminary results of R&D on VEPed cavities show removal dependence on cavity performance. Temperature oscillation asymmetry was also found during the VEP process. We will report these recent results and further R&D plan of Cornell VEP.  
 
WEOAB03 An Update on a Superconducting Photonic Band Gap Structure Resonator Experiment cavity, HOM, wakefield, niobium 2140
 
  • E.I. Simakov, W.B. Haynes, M.A. Madrid, F.P. Romero, T. Tajima, W.M. Tuzel
    LANL, Los Alamos, New Mexico, USA
  • C.H. Boulware, T.L. Grimm
    Niowave, Inc., Lansing, Michigan, USA
  
  Funding: This work is supported by the U.S. Department of Energy (DOE) Office of Science Early Career Research Program.
We present an update on the 2.1 GHz superconducting rf (SRF) photonic band gap (PBG) resonator experiment in Los Alamos. The SRF PBG cell was designed to operate at 2.1 GHz. PBG cells have great potential for outcoupling long-range wakefields in SRF accelerator structures without affecting the fundamental accelerating mode. Using PBG structures in superconducting particle accelerators will allow operation at higher frequencies and moving forward to significantly higher beam luminosities thus leading towards a completely new generation of colliders for high energy physics. However, the technology of fabrication of PBG accelerator cells from niobium has not been well developed to date. Here we report the results of our efforts to fabricate a 2.1 GHz PBG cell and to test it at high gradients in a liquid helium bath at the temperature of 2 Kelvin. The high gradient performance of the cell will be evaluated and the results will be compared to simulations with the CST Microwave Studio. 		 
slides icon Slides WEOAB03 [2.061 MB]  
 
WEEPPB011 Analysis of High Field Non-Linear Losses on SRF Surfaces Due to Specific Topographic Roughness simulation, superconductivity, niobium, feedback 2188
 
  • C. Xu
    The College of William and Mary, Williamsburg, USA
  • M.J. Kelley, C.E. Reece, C. Xu
    JLAB, Newport News, Virginia, USA
  
  Funding: This work is authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The high-field performance of SRF cavities will eventually be limited by the realization of fundamental material limits, whether it be Hc1 or Hsh, or some derivative thereof, at which the superconductivity is lost. Before reaching this fundamental field limit at the macro level, it must be encountered at localized, perhaps microscopic, sites of field enhancement due to local topography. If such sites are small enough, they may produce thermally stabilized normal-conducting regions which contribute non-linear losses when viewed from the macro resonant field perspective, and thus produce degradation in Q0. We have undertaken a calculation of local surface magnetic field enhancement from specific fine topographic structure by conformal mapping method and numerically. A solution of the resulting normal conducting volume has been derived and the corresponding RF ohmic loss simulated. 		 
 
WEEPPB015 Temperature Dependence of the Superheating Field: DC and RF Critical Fields cavity, niobium, electron, superconductivity 2197
 
  • N.R.A. Valles, M. Liepe
    CLASSE, Ithaca, New York, USA
  
  The superheating field is a metastable state at which the Meissner state persists at fields higher than would be predicted from steady-state energy considerations. Previous work demonstrated that a phenomenological approach based on the RF superheating field scaling near the critical temperature is also consistent with low temperature results. This work expands upon the RF results by measuring the DC superheating field, and comparing it to RF results and theoretical predictions.  
 
WEPPC001 Input Power Coupler for the IFMIF SRF Linac cryomodule, vacuum, low-level-rf, controls 2200
 
  • H. Jenhani, P. Bosland, P. Carbonnier, N. Grouas, P. Hardy, V.M. Hennion, F. Orsini, J. Plouin, B. Renard
    CEA/IRFU, Gif-sur-Yvette, France
  • S.J. Einarson, T.A. Treado
    CPI, Beverley, Massachusetts, USA
  
  The design phase of the IFMIF-EVEDA Power Couplers for the Superconductive HWR has been accomplished. TiN and copper coatings specifications have been validated on samples. A coupler window equipped with a truncated antenna and RF matching transition have been fabricated and tested to qualify the manufacturing processes and to demonstrate the technical feasibility of the coupler. Series of tests were successfully performed on these subassemblies. The last part of the design phase consists of the design validation by manufacturing two coupler prototypes and testing their performances at full power. Finishing processes and validation tests are on-going.  
 
WEPPC002 Impact of Trapped Flux and Thermal Gradients on the SRF Cavity Quality Factor cavity, niobium, superconducting-cavity, controls 2203
 
  • O. Kugeler, J. Knobloch, J.M. Vogt
    HZB, Berlin, Germany
  • S. Aull
    CERN, Geneva, Switzerland
  
  The obtained Q0 value of a superconducting niobium cavity is known to depend on various factors like the RRR of the Niobium material, crystallinity, chemical treatment history, the high-pressure rinsing process, or effectiveness of the magnetic shielding. We have observed that spatial thermal gradients over the cavity length during cool-down appear to contribute to a degradation of Q0. Measurements were performed in the Horizontal Bi-Cavity Test Facility (HoBiCaT) at HZB on TESLA type cavities as well as on disc- and rod-shaped niobium samples equipped with thermal, electrical and magnetic diagnostics. Possible explanations for the effect are discussed.  
 
WEPPC003 Component Qualification and Final Assembly of the S-DALINAC Injector Upgrade Module cavity, linac, niobium, shielding 2206
 
  • J. Conrad, R. Eichhorn, T. Kürzeder, A. Richter, S.T. Sievers
    TU Darmstadt, Darmstadt, Germany
  
  Funding: This work is supported by the DFG through SFB 634.
The injector of the S-DALINAC delivers currently electron beams of up to 10 MeV with a current of up to 60 μA. With the new cryostat-module an increase of both parameters, energies ranging to 14 MeV and currents up to 150 μA, are expected. For acceleration, the module houses two 20 cell elliptical niobium cavities which are used at a frequency of 3 GHz in liquid helium at 2 K. The RF power is delivered to the cavities through the different temperature stages by a WR-284 transition line which is connected to the resonator by a new waveguide-to-coax power coupler (being one of the major changes compared to the design of the existing module). We review on the design of the module and present the results of the first cool-down. Also, a report on additional new design features, e.g. piezo actuators for tuning at 2 K, and the production of the cavities will be given. 		 
 
WEPPC022 Elliptical SRF Cavity Design for PEFP Extension cavity, linac, coupling, proton 2251
 
  • H.S. Kim, Y.-S. Cho, J.-H. Jang, H.-J. Kwon
    KAERI, Daejon, Republic of Korea
  
  Funding: * This work is supported by the Ministry of Education, Science and Technology of the Korean Government.
To increase the beam energy up to 1 GeV by extending a PEFP 100-MeV proton linac, a study on the superconducting RF linac is underway. SRF technology is chosen due to its operational flexibility and lower beam loss, as well as its high accelerating performance and low operating cost. Preliminary study on the beam dynamics shows that two types of cavity with geometrical beta of 0.50 and 0.74 can cover the entire energy range from 100 MeV to 1 GeV. Assuming the achievable peak surface electric field to be 30 MV/m and 35 MV/m for medium and high beta cavity, respectively, we designed the six-cell elliptical cavities by optimizing the cavity parameters such as peak field ratio, inter-cell coupling and r/Q through the geometrical parameter sweep. The details of the SRF cavity design for PEFP extension will be presented. 		 
 
WEPPC023 Status and Progress of RF System for the PLS-II Storage Ring klystron, cryomodule, controls, LLRF 2254
 
  • M.-H. Chun, J.Y. Huang, Y.D. Joo, H.-S. Kang, H.-G. Kim, C.D. Park, H.J. Park, I.S. Park, Y.U. Sohn, I.H. Yu
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  Funding: Supported by the Korea Ministry of Science and Technology
The RF system for the Pohang Light Source (PLS) storage ring was upgraded for PLS-II project of 3.0GeV/400mA from 2.5GeV/200mA. the RF system is commissioning with five normal conducting(NC) RF cavities at total maximum RF power of 280kW to the cavities with two 300kW klystron and two 75kW klystron amplifiers in 2011. The super conducting(SC) cavities will be installed on August 2012 because of long delivery. Therefore three NC RF cavities will be replaced with two SC cavities with cryomodules, and operated with cryogenics, digital low level, and 300kW klystron high power system. Also we are preparing the third SC cavity stand to increase the storage ring current up to 400mA with all insertion devices operation. This paper describes the present installation, commissioning, operation status, upgrade progress, and future plan of the RF system for the upgraded project of PLS-II storage ring. 		 
 
WEPPC024 Preliminary Test of Superconducting RF Cavities for PLS-II cavity, cryomodule, vacuum, cryogenics 2257
 
  • Y.U. Sohn, M.-H. Chun, J.Y. Huang, Y.D. Joo, H.-S. Kang, H.-G. Kim, S.H. Nam, C.D. Park, H.J. Park, I.S. Park, I.H. Yu
    PAL, Pohang, Kyungbuk, Republic of Korea
  
  Funding: This project is supported by the Korea Ministry of Science and Technology.
The main part of the Installation for the PLS-II upgrade was finished in June and is on the way to user operation through elaborate commissioning. Up to now, the achievement is 150 mA beam current at 3 GeV with multi-bunch mode with 5 normal conducting cavities which served in the PLS before. After installation of 2 SRF cavities in the summer of 2012, the PLS-II will have 300 mA beam current with 20 IDs by 2 superconducting RF cavities until July, 2014. Finally, one more superconducting cavity will be added in August, 2014, and beam current will rise to 400 mA. The two SRF cavities are under test and conditioning. The two main subsystems, SRF cavities and ceramic windows were tested independently to confirm their performance. Each cavity recorded its accelerating voltage as 3.27 MV and 3.24 MV at 4.2K, respectively. Two RF windows also passed their specification, 300 kW CW traveling wave and 150 kW CW standing wave. The preliminary tests of SRF cryomodules are reported in the presentation. 		 
 
WEPPC029 Design and Development of an Octopus Thermometric System for the 704 MHz Single-cell SPL Cavity at CERN cavity, LabView, factory, proton 2266
 
  • K.C. Liao, L. Arnaudon, O. Brunner, E. Ciapala, D.C. Glenat, W. Weingarten
    CERN, Geneva, Switzerland
  
  The octopus thermometric system is designed for the 704 MHz superconducting proton linac (SPL) cavity to detect hot spots and X-rays caused by normal conducting defects and the impact of emission electrons. This system features an octopus body and tentacle structure for good contact with the cavity and easy assembly, a multiplexing circuit with integrated microprocessor for efficient readout and a high density temperature sensor arrangement in order to complete a high resolution temperature and X-ray map. The first prototype is being manufactured and investigations are undergoing for further development.  
poster icon Poster WEPPC029 [1.715 MB]  
 
WEPPC039 Development of a Half-Wave Resonator for Project X cavity, linac, cryomodule, ion 2295
 
  • P.N. Ostroumov, Z.A. Conway, R.L. Fischer, S.M. Gerbick, M. Kedzie, M.P. Kelly, B. Mustapha
    ANL, Argonne, USA
  • I.V. Gonin, S. Nagaitsev
    Fermilab, Batavia, USA
  
  Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics and Nuclear Physics, under Contract DE-AC02-76CH03000 and DE-AC02-06CH11357.
We have developed an optimized electromagnetic and mechanical design of a 162.5 MHz half-wave resonator (HWR) suitable for acceleration of high-intensity proton or H-minus beams in the energy range from 2 MeV to 10 MeV. The cavity design is based on recent advances in SRF technology for TEM-class structures being developed at ANL. Highly optimized EM parameters were achieved by adjusting the shapes of both inner and outer conductors. This new design will be processed with a new HWR horizontal electropolishing system after all mechanical work on the cavity including the welding of the helium jacket is complete. The prototype HWR is being fabricated by domestic vendors under ANL’s supervision. 		 
 
WEPPC040 Evaluation of VATSEAL Technology to Seal Waveguide Serving High-field Superconducting RF Cavities vacuum, cavity, impedance, radio-frequency 2298
 
  • B.K. Stillwell, J.D. Fuerst, J. Liu, G.J. Waldschmidt, G. Wu
    ANL, Argonne, USA
  
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A waveguide flange seal serving a high-field, superconducting, radio-frequency (SRF) cavity ideally possesses several characteristics. Seals must generally be ultrahigh-vacuum leak tight. Seals must also bridge the inner surfaces of connecting flanges for optimum transmission and minimal heating due to trapped modes. In addition, if seal contact areas are minimized, flange seals may serve as convenient thermal impedances. Finally, seals must be easily cleanable and not be prone to generate particulate matter during assembly and disassembly. A unique sealing technology known as VATSEAL may neatly address all of the above requirements. In this paper, we describe our evaluation of VATSEAL technology for use in SRF cavity assemblies. 		 
 
WEPPC041 Tests of SRF Deflecting Cavities at 2K cavity, vacuum, cryogenics, photon 2300
 
  • J.D. Fuerst, D. Horan, J. Kaluzny, A. Nassiri, T.L. Smith, G. Wu
    ANL, Argonne, USA
  
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS) at Argonne National Laboratory (ANL) is developing 2.8-GHz deflecting-mode superconducting rf cavities in collaboration with Jefferson Lab as part of a major facility upgrade. On-site testing of these cavities requires a new cryostat capable of operation at 2.0 K or less. The APS has leveraged facilities and expertise within ANL’s Physics Division to upgrade an existing test stand for continuous operation at temperatures as low as 1.7 K. A new cryogenic feedbox was fabricated and mated to an existing liquid helium “bucket” dewar with 0.6-m inside diameter and 1-m working depth. The configuration allows continuous sub-λ operation using warm vacuum pumping and helium make-up from the Physics Division’s existing cryoplant at heat loads up to 50 W dynamic, plus 15 W measured static load at 2.0 K. A 2.8-GHz TWT-based rf station has been installed and commissioned, providing up to 275 W of rf power. We describe the cryogenic and rf performance of the system and provide examples of cavity test results. 		 
 
WEPPC042 Low Impedance Bellows for High-current Beam Operations cryomodule, impedance, wakefield, electron 2303
 
  • G. Wu, K.-J. Kim, A. Nassiri, G.J. Waldschmidt, Y. Yang
    ANL, Argonne, USA
  • J.J. Feingold, J.D. Mammosser, R.A. Rimmer, H. Wang
    JLAB, Newport News, Virginia, USA
  • J. Jang, S.H. Kim
    POSTECH, Pohang, Kyungbuk, Republic of Korea
  
  Funding: Work Supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357
In particle accelerators, bellows are commonly used to connect beamline components. Such bellows are traditionally shielded to lower the beam impedance. Excessive beam impedance can cause overheating in the bellows, especially in high beam current operation. For an SRF-based accelerator, the bellows must also be particulate free. Many designs of shielded bellows incorporate rf slides or fingers that prevent convolutions from being exposed to wakefields. Unfortunately these mechanical structures tend to generate particulates that, if left in the SRF accelerator, can migrate into superconducting cavities, the accelerator's critical components. In this paper, we describe a prototype unshielded bellows that has low beam impedance and no risk of particulate generation. 		 
 
WEPPC046 Overview of Project X Superconducting RF Cavities and Cryomodules cavity, cryomodule, linac, focusing 2315
 
  • T.N. Khabiboulline, M.S. Champion, C.M. Ginsburg, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  The Project X Linac is based primarily on superconducting RF technology starting from a low beam energy of approximately 2.5 MeV up to the exit energy of 8 GeV. The Linac consists of 162.5 MHz half-wave cavities, 325 MHz single-spoke cavities, and two families of 650 MHz elliptical cavities - all operating in continuous-wave mode - up to a beam energy of 3 GeV. The beam is further accelerated up to 8 GeV in a pulsed mode ILC-like Linac utilizing 1.3 GHz cavities. In this paper we will give an overview of the design and status of the Project X superconducting RF cavities and cryomodules.  
 
WEPPC049 Individual RF Test Results of the Cavities Used in the First US-built ILC-type Cryomodule cavity, cryomodule, radio-frequency, linear-collider 2321
 
  • A. Hocker, A.C. Crawford, E.R. Harms, A. Lunin, D.A. Sergatskov, A.I. Sukhanov
    Fermilab, Batavia, USA
  • G.V. Eremeev, R.L. Geng
    JLAB, Newport News, Virginia, USA
  • J.P. Ozelis
    FRIB, East Lansing, USA
  
  Funding: Work supported in part by the U.S. Department of Energy under Contract No. DE-AC02-07CH11359.
Eight 1.3-GHz, nine-cell SRF cavities have been installed in a cryomodule intended to demonstrate the ILC design goal of 31.5 MV/m. These cavities all underwent two types of individual RF testing: a low-power continuous-wave test of the “bare” cavity and a high-power pulsed test of the “dressed” cavity. Presented here is a discussion of the results from these tests and a comparison of their performance in the two configurations. 		 
 
WEPPC052 High Gradient Tests of the Fermilab SSR1 Cavity cavity, multipactoring, vacuum, linac 2330
 
  • T.N. Khabiboulline, C.M. Ginsburg, I.V. Gonin, R.L. Madrak, O.S. Melnychuk, J.P. Ozelis, Y.M. Pischalnikov, L. Ristori, A.M. Rowe, D.A. Sergatskov, A.I. Sukhanov, I. Terechkine, R.L. Wagner, R.C. Webber, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  In Fermilab we are build and tested several superconducting Single Spoke Resonators (SSR1, β=0.22) which can be used for acceleration of low beta ions. Fist two cavities performed very well during cold test in Vertical Test Station at FNAL. One dressed cavity was also tested successfully in Horizontal Test Station. Currently we are building 8 cavity cryomodule for PIXIE project. Additional 10 cavities were manufactured in the industry and ongoing cold test results will be presented in this poster.  
 
WEPPC057 Design of SSR1 Single Spoke Resonators for PXIE cavity, niobium, cryomodule, coupling 2342
 
  • L. Ristori, M.H. Awida, I.V. Gonin, M. Merio, D. Passarelli, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
The Project X Injector Experiment (PXIE) at Fermilab contains one cryomodule of Single Spoke Resonators operating at 325 MHz with a geometrical beta of 0.2. Two prototypes have been tested successfully at high gradients in the Fermilab Vertical Test Stand (VTS). We have welded a Stainless Steel helium vessel on the first prototype and tested it in the spoke-dedicated Test Cryostat. With excellent results in hand, an order for ten bare resonators was placed with US industry. A new design for the helium vessel was developed for these resonators with the main goal of reducing the sensitivity of the resonator to variations of the helium pressure to meet the requirements of PXIE. A new tuner was developed despite the good results of the first prototype. The new design was inevitable due to the different behavior of the resonator in the new helium vessel. Other aspects were improved such as the maintainability of the tuner motor and piezoelectric actuators allowing their replacement from access ports on the cryomodule's vacuum vessel. 		 
 
WEPPC058 Development at ANL of a Copper-brazed Joint for the Coupling of the Niobium Cavity End Wall to the Stainless Steel Helium Vessel in the Fermilab SSR1 Resonator niobium, cavity, vacuum, coupling 2345
 
  • L. Ristori
    Fermilab, Batavia, USA
  • W.F. Toter
    ANL, Argonne, USA
  
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
In order to reduce the sensitivity of the Fermilab SSR1 resonator to helium pressure variations, it was concluded that the cavity and helium vessel end-walls needed to be structurally coupled by means of a transition ring. With the materials to be connected being Niobium and Stainless Steel, it was decided to utilize the same technology already developed for the cavity flanges which consists of a furnace-brazed joint utilizing oxygen-free electrolytic copper. Small-scale and full-scale annular samples have been constructed at Argonne National Laboratory and subject to tensile tests, thermal cycling and visual inspections to qualify the joint. The transition ring is electron-beam welded to the cavity and TIG welded to the helium vessel, the process is explained in detail. 		 
 
WEPPC065 Cleanroom Techniques to Improve Surface Cleanliness and Repeatability for SRF Coldmass Production cavity, vacuum, superconductivity, controls 2357
 
  • L. Popielarski, L.J. Dubbs, K. Elliott, I.M. Malloch, R. Oweiss, J. Popielarski
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by US DOE Cooperative Agreement DE-SC0000661 and Michigan State University.
The Facility for Rare Isotope Beams (FRIB) and ReA linear accelerator projects at Michigan State University (MSU) utilize Superconducting Radio-Frequency (SRF) cavities for their accelerating structures. The structures are cleaned and assembled in a cleanroom to reduce particle contamination. The project requires more than 350 SRF cavities. In preparation for production we want to maximize repeatable processes and reduce work time. The cleanroom assembly group at MSU investigates process techniques performed in the cleanroom. Various diagnostic tools; such as liquid particle counter, surface particle counter and airborne particle counter are used to quantify environments and optimize processes. We desire to define procedure specifications for cleaner processes and repeatability. We investigate effective part cleaning and storage, high pressure rinse and ultra pure water quality, and critical component rinsing. We study vacuum assembly, pump down and purge effects. The experiments are independent of cavity results with a focus to create cleanest surface and environment in the most effective manner. In this paper, we describe experiments, summarize the results and conclusions. 		 
 
WEPPC066 Niobium Reaction Kinetics: An Investigation into the Reactions Between Buffered Chemical Polish and Niobium and the Impact on SRF Cavity Etching niobium, cavity, superconducting-RF 2360
 
  • I.M. Malloch, L.J. Dubbs, K. Elliott, R. Oweiss, L. Popielarski
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by US DOE Cooperative Agreement DE-SC0000661 and Michigan State University.
In the SRF community, there is no definitive agreement on the precise reaction mechanism in the etching of niobium cavities by buffered chemical polish (BCP) mixtures. As a consequence, it is difficult to predict the heat produced during cavity etching. To gain a better understanding of the reaction kinetics of niobium and BCP, calorimetry experiments were performed to establish an experimental heat of reaction, and research was performed to determine a reasonable reaction scheme to allow for calculation of the theoretical heat of reaction. The results of the calorimetry experiments were in excellent agreement with one another and with the theoretical value. These results will allow for more accurate estimation of etch removal amounts on cavities without the need to perform time-intensive etch rate tests. Applying the experimental data to pre and post cavity etch ultrasonic thickness measurements has shown a significant improvement in the predictability of etch removal amounts in Facility for Rare Isotope Beams (FRIB) half-wave and quarter-wave resonators, and will allow for more reliable heat removal and prevention of Q-disease during other cavity etching procedures. 		 
 
WEPPC067 Dewar Testing of Coaxial Resonators at MSU linac, niobium, cryomodule, cavity 2363
 
  • J. Popielarski, E.C. Bernard, A. Facco, M. Hodek, F. Marti, D. Norton, G.J. Velianoff, J. Wlodarczak
    FRIB, East Lansing, Michigan, USA
  • A. Burrill, G.K. Davis
    JLAB, Newport News, Virginia, USA
  
  Funding: Work supported by US DOE Cooperative Agreement DE-SC0000661 and Michigan State University
Michigan State University is currently testing prototype and production cavities for two accelerator projects. 80.5 MHz β=0.085 quarter wave resonators (QWR) are being produced as part of a cryomodule for ReA3. 322 MHz β=0.53 half wave resonators (HWR) are being prototyped for a driver linac for the Facility for Rare Isotope Beams. This paper will discuss test results and how different cavity preparations effect cavity performs. Also various diagnostics methods have been developed, such as second sound quench location determination, and temperature mapping to determine hot spots from defects and multipacting location. 		 
 
WEPPC069 Construction, Evaluation, and Application of a Temperature Map for Multi-cell SRF Cavities cavity, controls, vacuum, superconductivity 2369
 
  • G.M. Ge, F. Furuta, D.L. Hartill, K.M.V. Ho, G.H. Hoffstaetter, E.N. Smith
    CLASSE, Ithaca, New York, USA
  
  Temperature mapping (T-mapping) system is able to locate hot-spot of SRF cavity, thus it is a very powerful tool for cavity’s Q-value research. Recently Cornell University is developing a T-mapping system for multi-cell SRF cavities. The system includes more than two thousands Allen-Bradley resistors. Electronic of the system uses multiplexing of sensors which is able to dramatically reduce wire numbers, and allow the whole system is feasible for multi-cell cavity application. A new cavity testing insert which is for T-mapping system has been constructed.  
 
WEPPC072 High Current Operation of the Cornell ERL Superconducting RF Injector Cryomodule HOM, cavity, cryomodule, damping 2378
 
  • M. Liepe, G.H. Hoffstaetter, S. Posen, P. Quigley, V. Veshcherevich
    CLASSE, Ithaca, New York, USA
  
  Cornell University has developed a SCRF injector cryomodule for the acceleration of high current, low emittance beams in continuous wave operation. This cryomodule is based on superconducting RF technology, and is currently under extensive testing in the Cornell ERL injector prototype with CW beam currents exceeding 25 mA. Strong damping of Higher-Order-Modes in the cavities is essential for high beam current operation, and is achieved by beamline RF absorber located at cryogenic temperatures in the beam pipe sections between the cavities. This paper gives an overview of the experience gained during the high beam current operation of the cryomodule.  
 
WEPPC073 Progress on Superconducting RF Work for the Cornell ERL cavity, linac, cryomodule, HOM 2381
 
  • M. Liepe, F. Furuta, G.M. Ge, Y. He, G.H. Hoffstaetter, T.I. O'Connell, S. Posen, J. Sears, M. Tigner, N.R.A. Valles, V. Veshcherevich
    CLASSE, Ithaca, New York, USA
  
  Cornell University is developing the superconducting RF technology required for the construction of a 100 mA hard X-ray light source driven by an Energy-Recovery Linac. Prototypes of all beam line components of the 5 GeV cw SRF main linac cryomodule have been fabricated and tested in detail. This work includes an optimized 7-cell SRF cavity, a broadband HOM beamline absorber, a cold frequency tuner, and a 5 kW CW RF input coupler. A one-cavity test cryomodule has been assembled for a first full cryomodule test of the main linac cavity, and is currently under testing. In this paper we give an overview of these extensive R&D activities at Cornell.  
 
WEPPC078 Recent Developments in the Cornell Nb3Sn Initiative cavity, niobium, linac, accelerating-gradient 2390
 
  • S. Posen, G.H. Hoffstaetter, M. Liepe, Y. Xie
    CLASSE, Ithaca, New York, USA
  
  Superconducting accelerator cavities coated with Nb3Sn have already demonstrated significantly higher unloaded quality factors than standard niobium cavities at surface magnetic fields <30 mT. Theoretical predictions suggest that the maximum critical field of such cavities could be twice that of niobium cavities. Significant facilities have been developed at Cornell University to fabricate Nb3Sn using the vapor diffusion technique. In this paper, recent progress is presented from our Nb3Sn program. The first RF results from a test of a Nb3Sn sample in a TE pillbox sample cavity are presented as well as first images of the newly constructed apparatus for coating full 1.3 GHz single cell cavities.  
 
WEPPC079 Residual Resistance Studies at Cornell cavity, linac, simulation, accelerating-gradient 2393
 
  • S. Posen, D. Gonnella, G.H. Hoffstaetter, M. Liepe
    CLASSE, Ithaca, New York, USA
  • J. Oh
    Cornell University, Ithaca, New York, USA
  
  The Cornell single-cell temperature mapping system has been adapted for use with ILC and Cornell ERL-shape superconducting accelerator cavities. The system was optimized for low-noise, high-precision measurements with the goal of measuring resistances as low as 1 nohms. Using this system, a T-map of an ILC single cell was obtained at accelerating fields below the onset of Q-slope and at temperatures at which BCS resistance is small, producing a measurement of the distribution of residual resistance over the surface of the cavity. Standard procedures were used in preparing the cavity to avoid Q-disease and trapped flux caused by cooling the cavity through its transition in the presence of magnetic fields. Studying the T-map gives clues to the source of residual resistance, so that steps can be taken to reduce it, thereby lowering losses and increasing Q0. The temperature map noise-reduction studies as well as the residual resistance results are presented in this paper.  
 
WEPPC084 Development of a Superconducting 500 MHz Multi-Spoke Cavity for Electron Linacs cavity, cryomodule, electron, niobium 2408
 
  • D. Gorelov, C.H. Boulware, T.L. Grimm
    Niowave, Inc., Lansing, Michigan, USA
  • S.U. De Silva, J.R. Delayen, C.S. Hopper, R.G. Olave
    ODU, Norfolk, Virginia, USA
  
  Funding: This work is supported by the US Department of Energy SBIR/STTR program through the Office of Nuclear Physics.
Multi-spoke cavities are well-known options for acceleration of heavy and light ions. A recently developed multi-spoke cavity for β=1 presents an attractive opportunity to use this cavity type for electron accelerators. One of the main attractive features of this cavity type is its compactness for relatively low frequency. A simplified design at 500 MHz allowed building of a multi-spoke cavity and cryomodule in a 2-year time frame with confidence and development of effective manufacturing techniques. It also constitutes an important step in proving the usefulness of this kind of cavity design for new applications in the electron machines. Niowave is now in a position to build on the success of this cavity to help advance the design of superconducting electron accelerators. Accelerating voltage of more then 4.3 MV in a single cavity at 4.5 K is expected with peak electric field of less then 21.7 MV/m, and peak magnetic field of less then 80 mT. The paper discusses the fabrication challenges of the complete cavity and the cryomodule, as well as room temperature and cryogenic test results. 		 
 
WEPPC085 Engineering of a Superconducting 400 MHz Crabbing Cavity for the LHC HiLumi Upgrade cavity, luminosity, niobium, collider 2411
 
  • D. Gorelov, T.L. Grimm
    Niowave, Inc., Lansing, Michigan, USA
  • S.U. De Silva, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  
  Funding: This work is supported by the US DOE-HEP SBIR/STTR program and the US DOE through the US LHC Accelerator Research Program (LARP).
The recently developed new simplified design for the 400 MHz LHC crabbing cavity presents attractive properties compared to conventional designs. The proposed approach can be equally compact in both transverse dimensions and allows horizontal as well as vertical deflection of the beam in the collider. The significant modification of the parallel-bar design with the bars merged to the side walls of the cavity gives improved properties, such as better mode separation and reduced surface fields*. A transverse deflecting voltage of 3 to 5 MV in a single cavity can be expected with the peak surface electric field lower then 50 MV/m and peak magnetic field below 100 mT. This paper presents engineering issues of the proof-of-concept crabbing cavity design and discusses the manufacturing techniques. The paper discusses present status of the project including fabrication of the niobium cavity, as well as room temperature and cryogenic testing.
* J.R. Delayen, S.U. De Silva, "Design of Superconducting Parallel-Bar Deflecting/Crabbing Cavities with Improved Properties," Proc. of 2011 PAC, New York, NY, USA, 2011, p. 1021. 		 
 
WEPPC089 SRF Cavity Performance Overview for the 12 GeV Upgrade cavity, cryomodule, radiation, HOM 2423
 
  • A. Burrill, G.K. Davis, C.E. Reece, A.V. Reilly, M. Stirbet
    JLAB, Newport News, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The CEBAF accelerator, a recirculating CW electron accelerator that is currently operating at Jefferson Laboratory, is in the process of having 10 new cryomodules installed to allow for the maximum beam energy to be increased from 6 GeV to 12 GeV. This upgrade required the fabrication, processing and RF qualification of 80, seven cell elliptical SRF cavities, a process that was completed in February 2012. The RF performance achieve in the vertical testing dewars has exceeded the design specification by ~25% and is a testament to the cavity design and processing cycle that has been implemented. This paper will provide a summary of the cavity RF performance in the vertical tests, as well as review the overall cavity processing cycle and duration for the project. 		 
 
WEPPC091 A Path to Higher Q0 with Large Grain Niobium Cavities cavity, niobium, accelerating-gradient, induction 2426
 
  • P. Dhakal, G. Ciovati, G.R. Myneni
    JLAB, Newport News, Virginia, USA
  
  The improvement of the quality factor Q0 of superconducting radio-frequency (SRF) cavities at medium accelerating gradients (~ 20 MV/m) is important in order to reduce the cryogenic losses in continuous wave accelerators for a variety of applications. In recent years, SRF cavities fabricated from ingot niobium have become a viable alternative to standard high-purity fine-grain Nb for the fabrication of high-performing SRF cavities with the possibility of significant cost reduction. Initial studies*,**, demonstrated the improvement of Q0 at medium field in cavities heat treated at 800-1000 °C without subsequent chemical etching. To further explore this treatment procedure, a new induction furnace with an all-niobium hot-zone was commissioned. A single-cell 1.5 GHz cavity fabricated from ingot material from CBMM, Brazil, with RRR~200, was heat treated with the new furnace in the temperature range 600-1400 °C for several hours. Residual resistance values below 5 nano Ω have been consistently achieved on this cavity as well as Q0 values above 4.5×1010 at 2 K and 100 mT peak surface magnetic field. Q0-values of the order of 1011 have been measured at 1.5 K.
* G. Ciovati, et al., Phys. Rev. ST Accel. Beams 13, 022002 (2010).
** G. Ciovati, et al., Proc. of the 15th Int. Conf. on RF Superconductivity, Chicago, July 25-29, 2011, paper TUPO051
 		 
 
WEPPC092 12 GeV Upgrade Project - Cryomodule Production cryomodule, cavity, HOM, controls 2429
 
  • J. Hogan, A. Burrill, G.K. Davis, M.A. Drury, M. Wiseman
    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.
The Thomas Jefferson National Accelerator Facility (Jefferson Lab) is producing ten 100+MV SRF cryomodules (C100) as part of the CEBAF 12 GeV Upgrade Project. Once installed, these cryomodules will become part of an integrated accelerator system upgrade that will result in doubling the energy of the CEBAF machine from 6 to 12 GeV. This paper will present a complete overview of the C100 cryomodule production process. The C100 cryomodule was designed to have the major components procured from private industry and assembled together at Jefferson Lab. In addition to measuring the integrated component performance, the performance of the individual components is verified prior to being released for production and assembly into a cryomodule. Following a comprehensive cold acceptance test of all subsystems, the completed C100 cryomodules are installed and commissioned in the CEBAF machine in preparation of accelerator operations. This overview of the cryomodule production process will include all principal performance measurements, acceptance criterion and up to date status of current activities.
The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes. 		 
 
WEPPC094 Optimizing Centrifugal Barrel Polishing for Mirror Finish SRFCavity and Rf Tests at Jefferson Lab cavity, radio-frequency, controls, superconductivity 2435
 
  • A.D. Palczewski, R.L. Geng, H. Tian
    JLAB, Newport News, Virginia, USA
  
  Funding: This work is authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
We performed Centrifugal Barrel Polishing (CBP) on a 1.3GHz fine grain ILC SRF cavity following a modified version of the recipe* originally developed at Fermilab (FNAL)**. We were able to obtain a mirror like surface similar to that obtained at FNAL, while reducing the number of CBP steps. This paper will discuss the change in surface and subsequent cavity performance before CBP on a raw cavity and post CBP, after a 800C bake (no pre-bake chemistry) and minimal controlled electro-polishing (below 10 micron). In addition to Q vs. Eacc thermometry maps with preheating characteristics and optical inspection of the cavity before and after CBP will also be shown.
* A. D. Palczewski et al., Proc. of SRF2011, THPO071 (2011).
** C.A. Cooper et al., FERMILAB-PUB-11-032-TD, (May 31, 2011).
 		 
 
WEPPC095 Evaluation of Silicon Diodes as In-situ Cryogenic Field Emission Detectors for SRF Cavity Development cavity, ion, radiation, cryogenics 2438
 
  • A.D. Palczewski, R.L. Geng
    JLAB, Newport News, Virginia, USA
  
  Funding: This work is authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
We performed in-situ cryogenic testing of five silicon diodes as possible candidates for field emission monitor of SRF cavities in vertical testing dewars and in cryo-modules. We evaluated diodes from 2 companies - from Hamamatsu corporation model S5821-02 (used at KEK)* and S1223-02; and from OSI Optoelectronics models OSD35-LR-A, XUV-50C, and FIL-UV20. The measurements were done by placing the diodes in superfluid liquid helium near a field emitting 9-cell cavity during its vertical test. For each diode, we will discuss their viability as a 2K cryogenic detector for FE mapping of SRF cavities and their directionality in such environments. We will also present calibration curves between the diodes and JLab’s standard radiation detector placed above the dewar top plate and within radiation shielding.
* H. Sakai et al., Proc of IPAC10, WEPEC028 p. 2950 (2010). 		 
 
WEPPC096 Exploring the Effect of AL2O3 ALD Coating on a High Gradient ILC Single-Cell Cavity cavity, niobium, electron, site 2441
 
  • G.V. Eremeev, A-M. Valente-Feliciano, A.T. Wu
    JLAB, Newport News, Virginia, USA
  • D. Gu
    ODU, Norfolk, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Encouraged by work at Argonne National Lab, we investigated atomic layer deposition technique for high gradient superconducting RF cavities at JLab with an ALD coating system of Old Dominion University located on the JLab site. The goal of this study was to look into the possibility of coating a dielectric layer on top of RF niobium surface at a lower temperature of 120 C as compared to ANL coatings at 200 C in order to preserve niobium pentooxide on niobium surface. The initial coatings showed complete, but non-uniform coatings of the surface with several areas exhibiting discoloration, which was probably due to the temperature variation during coatings. The initial coating showed a high RF losses, which were improved after discolored areas on the beam tubes were removed with HF rinse of the beam tubes only. The best result was 2·109 low field Q0 and Eacc = 18 MV/m limited by available power. 		 
 
WEPPC097 Development of Nb and Alternative Material Thin Films Tailored for SRF Applications ion, ECR, vacuum, plasma 2444
 
  • A-M. Valente-Feliciano, H.L. Phillips, C.E. Reece, J.K. Spradlin, X. Zhao
    JLAB, Newport News, Virginia, USA
  • B. Xiao
    The College of William and Mary, Williamsburg, USA
  
  Funding: *Authored by Jefferson Science Associates LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Avenues for the production of thin films tailored for Superconducting RF (SRF) applications are showing promise with recent developments in vacuum deposition techniques using energetic ions. JLab is using energetic condensation via Electron Cyclotron Resonance and High Power Impulse Magnetron Sputtering (HiPIMS) for the development of Nb films and multilayer SIS (superconductor-insulator-superconductor) structures to reach bulk Nb performance and beyond. Nb films with RRR comparable to bulk values are readily produced. The influence of the deposition energy on the material and RF properties of the Nb thin film is investigated with the characterization of their surface, structure, superconducting properties and RF response. Nucleation studies are investigating the best conditions to create a favorable template for growing the final SRF surface. This paper presents results on surface impedance measurements correlated with surface and material characterization for Nb and multilayered SIS films produced on a variety of substrates. 		 
 
WEPPC104 Tomography as a Diagnostic Tool for Plasma Etching of SRF Cavities plasma, cavity, niobium, diagnostics 2459
 
  • M. Nikolić, A.L. Godunov, S. Popović, A. Samolov, L. Vušković
    ODU, Norfolk, Virginia, USA
  • F. Čučkov
    Old Dominion University, Norfolk, USA
  
  Plasma based surface modification is a promising alternative for etching of superconductive radio frequency (SRF) cavities. A plasma processed SRF cavity presents a plasma reactor with limited or distorted symmetry. We are developing a tomographic reconstruction of local plasma parameters, as a diagnostic tool in the plasma etching setting of SRF cavities. The method is non-invasive and provides deep insight into the fundamental processes and phenomena during the plasma treatment of SRF cavities’ surfaces. Here we report on our progress in developing tomographic numerical method, based on 2D inverse Radon formula. We tested it on supersonic flowing microwave discharge maintained in the cylindrical quartz tube. Due to the model’s sensitivity to the noise signal in the experiment, an automated measurement system has been built with the aim to increase the overall precision of data acquisition as well as to stream line the measurement process.  
 
WEPPC105 Study of Etching Rate Uniformity in SRF Cavities cavity, plasma, electron, coupling 2462
 
  • J. Upadhyay, S. Popović, L. Vušković
    ODU, Norfolk, Virginia, USA
  • H.L. Phillips, A-M. Valente-Feliciano
    JLAB, Newport News, Virginia, USA
  
  Plasma based surface modification is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. The crucial aspect of the technology development is dependence of the etching rate and surface roughness on the frequency of the power supply, pressure, power level, driven electrode shape and chlorine concentration in gas mixture during plasma processing. To optimize the plasma parameters, we are using a single cell cavity with 20 sample holders symmetrically distributed over the cell. These holders are used as diagnostic ports for the measurement of the plasma parameters and as holders for the samples to be etched. The plasma properties are highly correlated with the shape of the driven electrode and the percentage of chlorine concentration in Argon/chlorine gas mixtures. The effect of the plasma parameters and chlorine gas concentration are investigated at RF (100 MHz) and microwave (2.45 GHz) frequencies.  
 
WEPPC108 Status of SRF Facilities at SNS cryomodule, linac, cavity, controls 2471
 
  • J. Saunders, R. Afanador, T. Xu
    ORNL RAD, Oak Ridge, Tennessee, USA
  • M.T. Crofford, M.P. Howell, S.-H. Kim, S.E. Stewart
    ORNL, Oak Ridge, Tennessee, USA
  
  SNS has recognized the need for developing in-house capability to ensure long term sustainability of the SCL. SNS has made substantial gains in the last 6 years in understanding SCL operation, including system and equipment limiting factors, and resolution of system and equipment issues. Significant effort and focus is required to assure ongoing success in the operation, maintenance, and improvement of the SCL and to address the requirements of the upgrade project for the Second Target Station. This interdependent effort includes implementation of demonstrated improvements, fabrication of spare cryomodules, cavity R&D to enhance machine performance, and related SRF facility developments. Cryomodule and vertical cavity testing facilities are being developed to demonstrate process capabilities and to further understand the collective limitations of installed cavities. The status and future plans for SRF facilities at SNS will be presented.  
 
WEPPC109 Superconducting RF Systems for eRHIC linac, electron, cavity, hadron 2474
 
  • S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, H. Hahn, D. Kayran, G.J. Mahler, G.T. McIntyre, C. Pai, I. Pinayev, V. Ptitsyn, J. Skaritka, R. Than, J.E. Tuozzolo, Q. Wu, W. Xu, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • S.A. Belomestnykh, V. Litvinenko, T. Xin
    Stony Brook University, Stony Brook, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Future electron-hadron collider eRHIC will consist of a six-pass 30-GeV electron ERL and one of RHIC storage rings operating with energy up to 250 GeV. The collider design extensively utilizes superconducting RF (SRF) technology in both electron and hadron parts. This paper describes various SRF systems, their requirements and parameters. 		 
 
WEPPC111 Multipacting Simulation ADN Test Results of BNL 704 MHz SRF Gun cavity, cathode, gun, simulation 2480
 
  • W. Xu, S.A. Belomestnykh, I. Ben-Zvi, C. Cullen, H. Hahn, X. Liang, G.T. McIntyre, D. Pate, S.P. Pontieri, C. Schultheiss, T. Seda, T.N. Tallerico, R. Than, R.J. Todd, S.J. Tuozzolo, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • J. Dai
    SBU, Stony Brook, New York, USA
  • L.R. Hammons
    Stony Brook University, Stony Brook, USA
  
  Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The BNL 704 MHz SRF gun has a grooved choke joint to support the photo-cathode. Due to the distortion of grooves at the choke joint during the BCP for the choke joint, several multipacting barriers showed up when it was tested with Nb cathode stalk at JLab. We built a setup to use the spare large grain SRF cavity to test and condition the multipacting at BNL with various power sources. The test is carried out with three steps: cavity, cavity with Nb cathode stalk, and cavity with copper cathode stalk. This paper summarizes the results of multipacting simulation, and presents large grain cavity test setup and the test results. 		 
 
WEPPC114 Design, Simulation and Conditioning of the Fundamental Power Couplers for BNL SRF Gun simulation, vacuum, gun, klystron 2489
 
  • W. Xu, Z. Altinbas, S.A. Belomestnykh, I. Ben-Zvi, S. Deonarine, D.M. Gassner, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, L. Masi, G.T. McIntyre, D. Pate, D. Phillips, T. Seda, A.N. Steszyn, T.N. Tallerico, R.J. Todd, D. Weiss, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • M.D. Cole, G.J. Whitbeck
    AES, Medford, NY, USA
  
  Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
The 704 MHz SRF gun for the BNL Energy Recovery Linac (ERL) prototype uses two fundamental power couplers (FPCs) to deliver up to total 1 MW of CW RF power into the half-cell cavity. To prepare the couplers for high-power RF service and process multipacting, the FPCs should be conditioned prior to installation into the gun cryomodule. A room-temperature test stand was configured for conditioning FPCs in full reflection regime with varied phase of the reflecting wave. The FPCs have been conditioned up to 250 kW in pulse mode and 125 kW in CW mode. The multipacting simulations were carried out with Track3P code developed at SLAC. The simulations matched the experimental results very well. This paper presents the FPC RF and thermal design, multipacting simulations and conditioning of the BNL gun FPCs. 		 
 
WEPPC115 High Q0 in Superconducting Niobium Cavities: Progress at FNAL and Future Plans cavity, niobium, factory, vacuum 2492
 
  • A. Grassellino, L.D. Cooley, C.M. Ginsburg, A. Romanenko, A.M. Rowe, V.P. Yakovlev
    Fermilab, Batavia, USA
  
  Consistent improvement in the quality factors of SRF cavities at medium surface fields of about 70 mT represents a direct cost savings factor for the proposed Project X CW linac and other SRF accelerator projects based on CW operation. Current state-of-the-art in SRF does not provide processing recipes to maximize the Q0 at those fields since a complete understanding of the mechanisms governing the quality factor at non-negligible surface fields is not yet developed. In this contribution we present results of the FNAL effort in both scientific understanding and practical improvements and discuss the directions we are pursuing for future research.  
 
WEPPC116 Depth Distribution of Losses in Superconducting Niobium Cavities cavity, niobium, positron, vacuum 2495
 
  • A. Romanenko, A. Grassellino, J.P. Ozelis
    Fermilab, Batavia, USA
  • H. Padamsee
    CLASSE, Ithaca, New York, USA
  
  In order to optimize performances of superconducting niobium cavities it is crucial to understand the structure of near-surface few tens of nanometers of the material. In particular, superconducting properties of niobium, which depend on the presence of impurities and/or defects, may be non-uniform in the magnetic field penetration depth. A few cavity experiments based on oxypolishing* and anodizing**,*** provided some insight into the problem, but the definitive understanding is not developed yet. In this contribution we report on the "depth profiling" of the near-surface RF layer using an alternative technique based on the hydrofluoric acid (HF) rinsing. Tumbled, electropolished and buffered chemical polished cavities have been investigated and tentative nanostructural interpretation is discussed.
* P. Kneisel, Proc. of the 1999 SRF Workshop, Santa Fe, USA
** G. Eremeev and H. Padamsee, Physica C 441 No. 1-2 (2006) 62
*** G. Ciovati, P. Kneisel and A. Gurevich, PRSTAB 10 (2007) 062002 		 
 
WEPPD002 The Purifier System for Helium Cryogenic Plant in NSRRC cryogenics, controls, cavity, synchrotron 2498
 
  • H.C. Li, S.-H. Chang, C.M. Cheng, W.-S. Chiou, F. Z. Hsiao, T.F. Lin, C.P. Liu, H.H. Tsai
    NSRRC, Hsinchu, Taiwan
  
  A cryogenic adsorber is a purifier cooled with liquid nitrogen that is used to trap impurities from gaseous helium in the helium cryogenic system. The output purity can be decreased to less than 5 ppm and the dew point to -62 °C. The maximum rate of flow of each adsorber is 95 Nm3/h. We installed five cryogenic adsorbers in the cryogenic system and completed its testing in 2011; five additional cryogenic adsorbers will be installed in 2012. The configuration, installation, test results and operation of an cryogenic adsorber system are reported herein.
"cryogenic adsorber","purifier" 		 
 
WEPPP035 Pushing the Gradient Limitations of Superconducting Photonic Band Gap Structure Cells HOM, wakefield, electron, higher-order-mode 2801
 
  • E.I. Simakov, W.B. Haynes, S.S. Kurennoy, J.F. O'Hara, E.R. Olivas, D.Y. Shchegolkov
    LANL, Los Alamos, New Mexico, USA
  
  Funding: This work is supported by the Department of Defense High Energy Laser Joint Technology Office through the Office of Naval Research.
We present a design of a superconducting photonic band gap (PBG) accelerator cell operating at 2.1 GHz. The cell is designed with the PBG rods that are specially shaped to reduce the peak magnetic fields and at the same time to preserve its effectiveness for suppression of the higher order modes (HOMs). It has been long recognized that PBG structures have great potential in reducing and even completely eliminating HOMs in accelerators. This is especially beneficial for superconducting electron accelerators for high power free-electron lasers (FELs), which are intended to provide high current continuous duty electron beams. Using PBG structures to reduce the prominent beam-breakup phenomena due to HOMs will allow significantly increased beam-breakup thresholds, and consequently will allow the increase of the frequency of SRF accelerators and the development of novel compact high-current accelerator modules for FELs. High gradient limitations of PBG resonators and the optimal arrangement of the wakefield couplers will be discussed in details in this presentation. 		 
 
WEPPP077 Control of RF Transients in Cavities Induced by Pulsed High Current Beams cavity, controls, feedback, linac 2891
 
  • F. Löhl, J. Dobbins, R.P.K. Kaplan, C.R. Strohman
    CLASSE, Ithaca, New York, USA
  
  Funding: Supported by NSF award DMR-0807731.
The Cornell ERL prototype injector is operated either in a cw or in a pulsed mode. In the latter case, the bunch trains, which have a duration of 100 ns to 10 microseconds and a beam current of up to 100 mA, generate transients in the RF cavity fields which severely distort the beam quality and cause beam loss. In this paper, we present a scheme we use to correct the fast transients based on an adaptive feed-forward method. 		 
 
WEPPR019 Catalogue of Losses for the IFMIF Prototype Accelerator rfq, linac, solenoid, quadrupole 2982
 
  • P.A.P. Nghiem, N. Chauvin, D. Uriot
    CEA/DSM/IRFU, France
  • M. Comunian
    INFN/LNL, Legnaro (PD), Italy
  • C. Oliver
    CIEMAT, Madrid, Spain
  
  For machine and personal protection purposes, precise knowledge of beam loss location and power are crucial, especially in a high intensity, high power accelerator like the IFMIF prototype. This paper aims at discussing the protocol of appropriate studies in order to give the catalogue of beam losses in different conditions: nominal, tuning and accidental. Then results of these studies are given.  
 
WEPPR094 Large Volume Resonant Microwave Discharge for Plasma Cleaning of a CEBAF 5-Cell Srf Cavity cavity, plasma, electron, coupling 3156
 
  • S. Ahmed, K. Macha, J.D. Mammosser
    JLAB, Newport News, Virginia, USA
  • M. Nikolić, S. Popović, J. Upadhyay, L. Vušković
    ODU, Norfolk, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S.
We report preliminary results on plasma generation in a 5-cell CEBAF SRF cavity for the application of cavity interior surface cleaning. CEBAF currently has ~300 of these five cell cavities installed in the JLab accelerator which are mostly limited by cavity surface contamination. The development of an in-situ cavity surface cleaning method utilizing a resonant microwave discharge could lead to significant performance improvement. This microwave discharge is currently being used for set of plasma cleaning procedures targeted to the removal of various organic, metal and metal oxide impurities. These contaminants are responsible for the increase of surface resistance and the reduction of RF performance in installed cavities. CEBAF five cell cavity volume is ~ 0.5 m2, which places the discharge in the category of large-volume plasmas. Our preliminary study includes microwave breakdown and optical spectroscopy, which was used to define the operating pressure range and the rate of removal of organic impurities. 		 
 
THPPC093 SRF Cavity Surface Topography Characterization Using Replica Techniques cavity, niobium, superconductivity, radio-frequency 3497
 
  • C. Xu, M.J. Kelley
    The College of William and Mary, Williamsburg, USA
  • C.E. Reece
    JLAB, Newport News, Virginia, USA
  
  Funding: This work is authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
To better understand the roll of topography on SRF cavity performance, we seek to obtain detailed topographic information from the curved practical cavity surfaces. Replicas taken from a cavity interior surface provide internal surface molds for fine Atomic Force Microscopy (AFM) and stylus profilometry. In this study, we confirm the replica resolution both on surface local defects such as grain boundary and etching pits and compare the surface uniform roughness with the aid of Power Spectral Density (PSD) where we can statistically obtain roughness parameters at different scales. A series of sampling locations are at the same magnetic field chosen at the same latitude on a single cell cavity to confirm the uniformity. Another series of sampling locations at different magnetic field amplitudes are chosen for this replica on the same cavity for later power loss calculation. We also show that application of the replica followed by rinsing does not adversely affect the cavity performance. 		 
 
THPPP068 Investigation of a Multi-cell Cavity Structure Proposed for Improved Hydroforming cavity, focusing, coupling, HOM 3895
 
  • K.R. Shin
    ORNL RAD, Oak Ridge, Tennessee, USA
  • A.E. Fathy
    University of Tennessee, Knoxville, Tennessee, USA
  • J.A. Holmes, Y.W. Kang
    ORNL, Oak Ridge, Tennessee, USA
  
  A multi-cell cavity structure with rectangular coupling aperture between cavity cells is proposed. This investigation is to study the RF properties of such structure that may provide high yield in hydroforming. In mechanical point of view, the rectangular aperture iris may provide much improved structure quality in hydroforming since it can help to reduce the stress incurring within the sheet metal with improved structural malleability. The necking procedure can be easier because of greater perimeter in the iris geometry. Peak electric and magnetic fields per accelerating gradient may increase however, compared to traditional TESLA type elliptical cavity structure. The rectangular iris shape provides asymmetric transverse focusing per half RF period. If the horizontal and vertical rectangular irises are interleaved, the net transverse focusing may be achieved. 3D simulations with CST MWS have been carried out to analyze EM field properties and the cavity parameters.  
 
THPPP075 Present Status and Developments of the Linear IFMIF Prototype Accelerator (LIPAc) rfq, cavity, solenoid, linac 3910
 
  • A. Mosnier, P. Cara, R. Heidinger
    Fusion for Energy, Garching, Germany
  • P.-Y. Beauvais, S. Chel
    CEA/IRFU, Gif-sur-Yvette, France
  • A. Facco, A. Pisent
    INFN/LNL, Legnaro (PD), Italy
  • A. Ibarra, J. Molla
    CIEMAT, Madrid, Spain
  • V. Massaut, D. Vandeplassche
    SCK•CEN, Mol, Belgium
  • H. Matsumoto, G. Pruneri, Ch. Vermare
    IFMIF/EVEDA, Rokkasho, Japan
  • M. Sugimoto, H. Suzuki
    JAEA, Aomori, Japan
  
  The International Fusion Materials Irradiation Facility (IFMIF) aiming at generating materials irradiation test data for DEMO and future fusion power plants is based on an accelerator-driven, D-Li neutron source to produce high energy neutrons at sufficient intensity and irradiation volume. IFMIF Engineering Validation and Engineering Design Activities (EVEDA) have been conducted since mid 2007 in the framework of the Broader Approach Agreement and the scope of the project has been recently revised to set priority on the validation activities, especially on the Accelerator Prototype (LIPAc) with extending the duration up to mid 2017 in order to better fit the development of the challenging components and the commissioning of the whole accelerator. This paper summarizes the present status of the LIPAc, currently under construction at Rokkasho in Japan, outlines the engineering design and the developments of the major components, as well as the expected outcomes of the engineering work, associated with the experimental program.  
 
THPPR012 Lorentz Force Compensation for Long Pulses in SRF Cavities cavity, linac, controls, cryomodule 3990
 
  • Y.M. Pischalnikov, G.I. Cancelo, B. Chase, D.J. Crawford, D.R. Edstrom, Jr, E.R. Harms, R.A. Kostin, W. Schappert, N. Solyak
    Fermilab, Batavia, USA
  
  Lorentz force compensation of 8ms pulses in Tesla style elliptical cavities has been studied in Fermilab SRF Test Facility. Detuning measurements and compensation results are presented.  
 
THPPR028 Telephone Alarm Broadcasting for TPS RF System monitoring, synchrotron, status, storage-ring 4026
 
  • Y.-H. Lin, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Ch. Wang, M.-S. Yeh, T.-C. Yu
    NSRRC, Hsinchu, Taiwan
  
  The Taiwan Photon Source (TPS) consists of three 500-MHz RF systems: two sets RF systems with KEKB-type single-cell SRF modules are used for the 3-GeV storage ring, and one with five-cell Petra cavities at room temperature is used for booster synchrotron. To monitor the status of the RF systems and to broadcast the error/alarm messages to the RF guys, we develop a telephone alarm broadcasting system. This introduces the hardware and software structure of the alarm broadcasting system.  
 
FRXBA01 Overview of Recent Progress on High Repetition Rate, High Brightness Electron Guns gun, cathode, electron, brightness 4160
 
  • F. Sannibale
    LBNL, Berkeley, California, USA
  
  In the last few years, the formidable results of x-ray light sources based on FELs opened the door to classes of experiments not accessible before. Operating facilities have relatively low repetition rates (~ 10-100 Hz), and the natural step forward consists in the development of FEL light sources capable of extending their rates by orders of magnitude in the MHz regime. Additionally, ERL based x-ray facilities with their promise of outstanding performance also require extremely high, GHz-class repetition rates. The development of such facilities would represent the next revolutionary step in terms of science capability. To operate such light sources, an electron injector capable of MHz/GHz repetition rates and with the brightness required by X-ray FELs or ERLs is required. Such injector presently does not exist. In response to that, many groups around the world are intensively working on different schemes and technologies that show the potential for achieving the desired results. This presentation includes a description of the requirements for such injectors, an overview of the pursued technologies, and a review of the results obtained so far by the groups active in the field.  
slides icon Slides FRXBA01 [6.290 MB]