• L. R. Evans
  

• T. Tortschanoff
  
• R. Burgmer, H.-U. Klein, D. Krischel, B. Schellong, P. Schmidt
  ACCEL, Bergisch Gladbach
• M. Durante, A. Payn, J.-M. Rifflet, F. Simon
  CEA, Gif-sur-Yvette
• M. Modena, Y. Papaphilippou, L. Rossi, K. M. Schirm
  CERN, Geneva

• H.-H. Chen
  
• C.-H. Chang, T.-C. Fan, M.-H. Huang, C.-S. Hwang, J. C. Jan, F.-Y. Lin
  NSRRC, Hsinchu

• F. Z. Hsiao
  
• S.-H. Chang, W.-S. Chiou, H. C. Li, H. H. Tsai
  NSRRC, Hsinchu

• H. H. Tsai
  
• S.-H. Chang, W.-S. Chiou, F. Z. Hsiao, H. C. Li
  NSRRC, Hsinchu

• N. V. Mokhov
  
• P. Ferracin, G. L. Sabbi
  LBNL, Berkeley, California
• V. Kashikhin, M. Monville
  Fermilab, Batavia, Illinois

At the LHC upgrade luminosity of 10³⁵ cm^-2 s^-1, collision product power in excess of a kW is deposited in the inner triplet quadrupoles. The quadrupole field sweeps secondary particles from pp-collisions into the superconducting coils, concentrating the power deposition at the magnetic mid-planes. The local peak power density can substantially exceed the conductor quench limits and reduce component lifetime. Under these conditions, block-coil geometries may result in overall improved performance by removing the superconductor from the magnetic mid-planes and/or allowing increased shielding at such locations. First realistic energy deposition simulations are performed for an interaction region based on block-coil quadrupoles with parameters suitable for the LHC upgrade. Results are presented on 3-D distributions of power density and accumulated dose in the inner triplet components as well as on dynamic heat loads on the cryogenic system. Optimization studies are performed on configuration and parameters of the beam pipe, cold bore and cooling channels. The feasibility of the proposed design is discussed.

• P. Quigley
  
• S. A. Belomestnykh, M. Liepe, V. Medjidzade, J. Sears, V. Veshcherevich
  CLASSE, Ithaca

Cornell is building a 1.3 GHz Injector Cryomodule for an ERL prototype. The cryomodule consists of five two-cell niobium cavities each cavity having two coaxial power input couplers. Cavity and coupler pairs will require acceptance testing at high power prior to assembly in the injector cryomodule. A liquid nitrogen cryostat for testing the couplers at high power has been built and the first input coupler test is complete. In addition, a Horizontal Test Cryostat (HTC) is being built to test input coupler pairs and cavities as a set. The first HTC test is scheduled for spring 2007. Details for instrumentation of the Coupler Test Cryostat (CTC) and HTC are presented.

• D. Stout
  
• S. Assadi, I. E. Campisi, F. Casagrande, M. T. Crofford, W. R. DeVan, X. Geng, T. W. Hardek, S. Henderson, M. P. Howell, Y. W. Kang, W. C. Stone, W. H. Strong, D. C. Williams, P. A. Wright
  ORNL, Oak Ridge, Tennessee

The SNS project was completed with only limited SRF facilities installed as part of the project, namely a 5 MW, 805 MHz RF test stand, a fundamental power coupler processing system, a concrete test cave shell, and temporary cleaning/assembly facilities. A concerted effort has been initiated to install the infrastructure and equipment necessary to maintain and repair the superconducting Linac, and to support power upgrade R&D. Installation of a Class10/100/10,000 cleanroom and outfitting of the test cave with RF, vacuum, controls, personnel protection and cryogenics systems is underway. A horizontal cryostat, which can house a helium vessel/cavity and fundamental power coupler for full power, pulsed testing, is being procured. Equipment for cryomodule assembly/disassembly and cavity processing also is being designed. This effort, while derived from the experience of the SRF community, will provide a unique high power test capability as well as long term maintenance capabilities. This paper presents the current status and the future plans for the SNS SRF facilities.

• P. He
  
• M. Anerella, S. Aydin, G. Ganetis, M. Harrison, A. K. Jain, B. Parker
  BNL, Upton, Long Island, New York

The conceptual design of compact superconducting magnets for the International Linear Collider final focus is presently under development at BNL. A primary concern in using superconducting quadrupoles is the potential for inducing additional vibrations from cryogenic operation. We have employed a Laser Doppler Vibrometer system to measure the vibrations at resolutions ~1 nm (at frequencies above ~8 Hz) in a spare RHIC quadrupole coldmass under cryogenic conditions. Some preliminary results of these studies were presented at the Nanobeam 2005 workshop*. These results were limited in resolution due to a rather large motion of the laser head itself. As a first step towards improving the measurement quality, an actively stabilized isolation table was used to reduce the motion of the laser holder. The improved set-up will be described, and vibration spectra measured at cryogenic temperatures, both with and without helium flow, will be presented.

*A. Jain, et al., Nanobeam 2005, Kyoto, Japan, Oct.17-21, 2005; paper WG2d-05; available at http://wwwal.kuicr.kyoto-u.ac.jp/NanoBM .

• C. J. Liaw
  
• R. Schroeder, R. Sikora
  BNL, Upton, Long Island, New York

• R. Tolle
  
• T. Bergmark, S. Johnson, T. Johnson, T. Lofnes, G. Norman, T. Peterson
  Uppsala University, Uppsala
• K. Bongardt, J. Dietrich, F. M. Esser, O. Felden, R. Greven, G. Hansen, F. Klehr, A. Lehrach, B. Lorentz, R. Maier, D. Prasuhn, A. Raccanelli, M. Schmitt, Y. Senichev, E. Senicheva, R. Stassen, H. Stockhorst
  FZJ, Julich
• B. Gålnander, D. Reistad
  TSL, Uppsala
• F. Hinterberger
  Universität Bonn, Helmholtz-Institut für Strahlen- und Kernphysik, Bonn
• K. Rathsman
  UU/ISV, Uppsala
• M. Steck
  GSI, Darmstadt

• F. Caspers
  
• P. Borowiec, T. Kroyer, Z. Sulek, L. R. Williams
  CERN, Geneva

• K. Foraz
  
• E. Barbero-Soto, H. Gaillard, C. Hauviller, S. Weisz
  CERN, Geneva

• P. Marchand
  
• P. Bosland, P. Bredy
  CEA, Gif-sur-Yvette
• H. D. Dias, M. D. Diop, M. E. El Ajjouri, J. L. Labelle, R. L. Lopes, M. Louvet, C. M. Monnot, F. Ribeiro, T. Ruan, R. Sreedharan, K. Tavakoli, C. G. Thomas-Madec
  SOLEIL, Gif-sur-Yvette

• H. Podlech
  
• A. Bechtold, H. Liebermann, U. Ratzinger
  IAP, Frankfurt am Main

The superconducting CH-structure is the first multi-cell cavity for the acceleration of low and medium energy ions and protons. A superconducting prototype cavity has been built and several cold tests have been performed at the IAP in Frankfurt. After the detection of a field emission centre the cavity will be treated by buffered chemical polishing and high pressure rinsing. Additionally the cavity is being prepared for tests in a horizontal cryostat with slow and fast tuner system. We present the status of these developments and the test results which have been gained recently.

• R. Amirikas
  
• A. Bertolini, W. Bialowons
  DESY, Hamburg

The European X-ray Free Electron Laser (XFEL) and the International Linear Collider (ILC) superconducting accelerating modules, containing a string of Niobium (Nb) cavities and a quadrupole, will operate at 2K. In this paper, we will report on the vibration stability studies of a high gradient XFEL/ILC type III superconducting accelerating module quadrupole operating at 4.5K. Measurements are performed via geophones affixed on the cold mass in both horizontal and vertical directions. This data will be compared with piezoelectric accelerometers for the same module. The goal is to study the stability of the cold quadrupole and to compare the results with room temperature conditions.

• T. Semba
  
• Y. Itou, S. Kajiura, T. Masumoto, T. Tagawa
  Hitachi Ltd., Ibaraki-ken
• S. Noguchi, N. Ohuchi, K. Saito, A. Terashima, K. Tsuchiya
  KEK, Ibaraki

• I. S. Park
  
• J. Choi, C. W. Chung, M.-S. Hong, W. H. Hwang, D. T. Kim, Y. C. Kim, I. S. Ko, H. C. Kwon, Y. U. Sohn
  PAL, Pohang, Kyungbuk
• S. W. Kim, S. H. Kim, S. K. Song
  RIST, Pohang

Pohang Accelerator Laboratory has studied SRF cavity and set up SRF test laboratory from January 2006. The first activity for SRF research was to develop SRF 3rd harmonic cavity for Pohang Light Source, which was designed, fabricated and tested in 2006. The cryostat are under design. The fabrication of ICHIRO cavity, which is ILC ACD cavity, is PAL's second activity related to SRF. Deep drawing, trimming and welding by electron beam for a 9-cell ICHIRO cavity were done in PAL. The polishing processes for the RF surface including electropolishing were done in KEK under the collaboration between two institutes. This will be tested with real beam in STF-1 of KEK in second half period of 2007. This paper reports the results of fabrication of ICHIRO single- and nine-cell cavities performed in PAL.

• K. W. Shepard
  
• Z. A. Conway, J. D. Fuerst, M. P. Kelly, G. J. Waldschmidt
  ANL, Argonne, Illinois
• A. M. Porcellato
  INFN/LNL, Legnaro, Padova

This paper reports the development of a 5-10 kW cw variable coupler for 345 MHz spoke-loaded superconducting (SC)cavities. The coupler inserts an 80K copper loop into a 5 cm diameter coupling port on several types of spoke-loaded cavity operating at 2 - 4K. The coupling loop can be moved during operation to vary the coupling over a range of 40 dB. The coupler is designed to facilitate high-pressure water rinsing and low-particulate clean assembly. Design details and operating characteristics are discussed.

• E. R. Harms
  
• T. T. Arkan, L. Bellantoni, H. Carter, H. Edwards, M. Foley, T. N. Khabiboulline, D. V. Mitchell, D. R. Olis, A. M. Rowe, N. Solyak
  Fermilab, Batavia, Illinois

Fermilab is involved in an effort to assemble 3.9 GHz superconducting RF cavities into a four cavity cryomodule for use at the DESY TTF/FLASH facility as a third harmonic structure. The design gradient of these cavities is 14 MV/m limited by thermal heat transfer. This effort involves design, fabrication, intermediate testing, assembly, and eventual delivery of the cryomodule. We report on all facets of this enterprise from design through future plans. Included will be test results of single 9-cell cavities, lessons learned, and current status.

• J. Li
  
• N. Solyak
  Fermilab, Batavia, Illinois
• T. Wong
  Illinois Institute of Technology, Chicago, Illinois

Fermilab has developed a third harmonic superconducting cavity operating at the frequency of 3.9 GHz to improve the beam performance for the FLASH user facility at DESY. It is interesting to investigate the coupling interaction between the SRF cavity and the power coupler with or without beam loading. The coupling of the power coupler to the cavity needs to be determined to minimize the power consumption and guarantee the best performance for a given beam current. In this paper, we build and analyze an equivalent circuit model containing a series of lumped elements to represent the resonant system. An analytic solution of the required power from the generator as a function of the system parameters has also been given based on a vector diagram.

• M. McGee
  
• Y. M. Pischalnikov
  Fermilab, Batavia, Illinois

Operated by Universities Research Association, Inc., under Contract No. DE-AC02-76CH03000 with the U. S. Department of Energy#mcgee@fnal.gov

• J. P. Ozelis
  
• R. H. Carcagno, C. M. Ginsburg, Y. Huang, B. Norris, T. Peterson, V. Poloubotko, R. Rabehl, I. Rakhno, C. Reid, D. A. Sergatskov, C. Sylvester, M. Wong, C. Worel
  Fermilab, Batavia, Illinois

As part of a program to improve cavity performance reproducibility for the ILC, Fermilab is developing a facility for vertical testing of SRF cavities. It operates at a nominal temperature of 2K, using an existing cryoplant that can supply LHe in excess of 20g/sec and provides steady-state bath pumping capacity of 125W at 2K. The below-grade cryostat consists of a 4.9m long vacuum vessel and 4.5m long LHe vessel. The cryostat is equipped with external and internal magnetic shielding to reduce the ambient magnetic field to <10mG. Internal fixed and external movable radiation shielding ensures that radiation levels from heavily field-emitting cavities remain low. In the event that radiation levels exceed allowable limits, an integrated personnel safety system consisting of RF switches, interlocks, and area radiation monitors disables RF power to the cavity. In anticipation of increased throughput requirements that may be met with additional test stand installations, sub-systems have been designed to be easily upgradeable or to already meet these anticipated needs. Detailed facility designs, performance during system commissioning, and results from initial cavity tests are presented.

• J. Popielarski
  
• T. L. Grimm, W. Hartung, R. C. York
  NSCL, East Lansing, Michigan

The Spallation Neutron Source (Oak Ridge), the proposed 8 GeV Proton Driver (Fermilab), and the proposed Rare Isotope Accelerator use multicell elliptical SRF cavities to provide much of the accelerating voltage. This makes the elliptical cavity segment the most expensive part of the linac. A new type of accelerating structure called a half-reentrant elliptical cavity can potentially improve upon existing elliptical designs by reducing the cryogenic load by as much as 30% for the same accelerating voltage. Alternatively, with the same peak surface magnetic field as traditional elliptical cavities, it is anticipated that half-reentrant designs could operate at up to 25% higher accelerating gradient. With a half-reentrant shape, liquids can drain easily during chemical etching and high pressure rinsing, which allows standard multicell processing techniques to be used. A half-reentrant cavity for β = v/c = 1, suitable for the proposed ILC, has been designed and fabricated, with RF tests in progress*. In this paper, we present electromagnetic designs for three half-reentrant cell shapes suitable for an ion or proton linac (β = 0.47, 0.61 and 0.81, f = 805 or 1300 MHz).

* M. Meidlinger et al., in Proc. XXIII Int. Linac Conf., Knoxville, TN, Aug 2006

• A. Canabal
  
• G. B. Bowden, V. A. Dolgashev, J. R. Lewandowski, C. D. Nantista, S. G. Tantawi
  SLAC, Menlo Park, California
• I. E. Campisi
  ORNL, Oak Ridge, Tennessee
• T. Tajima
  LANL, Los Alamos, New Mexico

• F. L. Krawczyk
  
• G. O. Bolme, W. L. Clark, J. P. Kelley, F. A. Martinez, D. C. Nguyen, K. A. Young
  LANL, Los Alamos, New Mexico
• J. Rathke, D. L. Schrage, T. Schultheiss, L. M. Young
  AES, Medford, NY

An experiment has been conducted to measure small differences in cavity Q caused by various cavity surface treatments. A requirement of the experiment was that it show little sensitivity to the reassembly with various test pieces. We chose a coaxial half-wave resonator, with an outer conductor extending significantly beyond the length of the inner conductor. The outer conductor acts as a cut-off tube, eliminating the need for electric termination and thus any RF-contacts that can influence the Q-measurements. The experiment is aimed at qualifying the performance of cyanide-copper plated GlidCop in comparison with that of a machined GlidCop surface. To maximize the sensitivity of the measurement we use a fixed outer conductor made of annealed OFE copper and only replace the inner conductor, which is mounted on a low-loss Teflon pedestal located in the low electric field region. The Q-values of machined GlidCop and cyanide-copper plated GlidCop inner conductors are measured against the reference Q of the annealed OFE co-axial cavity. This simple configuration allows a statistically significant number of repetitions of measurements and should provide accurate comparative measurements.

• P. Kneisel
  
• R. Bundy, G. Ciovati, W. Clemens, D. Forehand, B. Golden, S. Manning, R. Manus, R. B. Overton, R. A. Rimmer, G. Slack, L. Turlington, H. Wang
  Jefferson Lab, Newport News, Virginia
• F. Marhauser
  JLAB, Newport News, Virginia

In a previous paper the cavity* design for an Ampere-class cryomodule was introduced. We have since fabricated a 1500 MHz version of a single cell cavity with waveguide couplers for HOM and fundamental power, attached to one end of the cavity, a 5-cell cavity made from large grain niobium without couplers and a complete 5-cell cavity from polycrystalline niobium featuring waveguide couplers on both ends. A 750 MHz single cell cavity without endgroups has also been manufactured to get some information about obtainable Q-values, gradients and multipacting behavior at lower frequency. This contribution reports on the various tests of these cavities.

* R. A.Rimmer et al.; EPAC 2006, paper MOPCH182

• I. E. Campisi
  
• S. Assadi, F. Casagrande, M. S. Champion, M. T. Crofford, G. W. Dodson, J. Galambos, M. Giannella, S. Henderson, M. P. Howell, Y. W. Kang, K.-U. Kasemir, S.-H. Kim, Z. Kursun, P. Ladd, H. Ma, D. Stout, W. H. Strong, Y. Zhang
  ORNL, Oak Ridge, Tennessee

The Superconducting Linac at SNS has been operating with beam for almost two years. As the first operational pulsed superconducting linac, many of the aspect of its performance were unknown and unpredictable. A lot of experience has been gathered during the commissioning of its components, during the beam turn on and during operation at increasingly higher beam power. Some cryomodules have been cold for well over two years and have been extensively tested. The operation has been consistently conducted at 4.4 K and 10 and 15 pulses per second, with some cryomodules tested at 30 and 60 pps and some tests performed at 2 K. Careful balance between safe operational limits and the study of conditions, parameters and components that create physical limits has been achieved. This paper presents the experience and the performance of the superconducting cavities and of the associated systems with and without beam.

• S.-H. Kim
  
• I. E. Campisi, F. Casagrande, M. T. Crofford, Y. W. Kang, Z. Kursun, D. Stout, A. V. Vassioutchenko
  ORNL, Oak Ridge, Tennessee

The cryomodule tests are on going to have better understandings of physics as a whole and eventually to provide safe and reliable operation for neutron production. Some features are revealed to be interesting issues and need more attentions than expected, such as operating condition, collective effects between cavities, HOM coupler issues, end-group stability, cavity-coupler interactions, and vacuum/gas physics, waiting for more investigations. Up to now SNS cryomodules were mainly tested at 4.4 K, 10 pulse per second (pps) and 30 pps/60 pps tests are under progress. This paper presents the experiences and the observations during tests of cryomodules.

• M. Liepe
  
• S. A. Belomestnykh, E. P. Chojnacki, V. Medjidzade, H. Padamsee, P. Quigley, J. Sears, V. D. Shemelin, V. Veshcherevich
  CLASSE, Ithaca

Cornell University is developing and fabricating a SRF injector cryomodule for the acceleration of the high current (100 mA) beam in the Cornell ERL prototype and ERL light source. Major challenges include emittance preservation of the low energy, ultra low emittance beam, cw cavity operation, and strong HOM damping with efficient HOM power extraction. Prototypes have been completed for the 2-cell niobium cavity with helium vessel, coaxial blade tuner with piezo fine tuners, twin high power input couplers, and beam line HOM absorbers loaded with ferrites and ceramics. Axial symmetry of HOM absorbers, together with two symmetrically placed input couplers per cavity, avoids transverse on-axis fields, which would cause emittance growth. A one-cavity cryostat has been designed following concepts of the TTF cryostat, and is presently under fabrication and assembly. The cryostat design has been optimized for precise cavity alignment, good magnetic shielding, and high dynamic cryogenic loads from the RF cavities, input couplers, and HOM loads. In this paper we report on the status of the assembly and first test of the one-cavity test cryostat.

• P. Bosland
  
• P.-E. Bernaudin, G. Devanz, A. Perolat, C. G. Thomas-Madec
  CEA, Gif-sur-Yvette
• S. Blivet, T. Junquera, D. Longuevergne, F. Lutton, G. Martinet, G. Olry, H. Saugnac
  IPN, Orsay
• R. Ferdinand
  GANIL, Caen
• M. Fruneau, Y. Gomez-Martinez, F. Vezzu
  LPSC, Grenoble

• J. Urbin
  
• R. D. Nolte
  Air Products & Chemicals, Inc., Allentown, Pennsylvania

• J. Yoshida
  
• K. Hara, K. Hosoyama, Y. Kojima, H. Nakai, K. Nakanishi
  KEK, Ibaraki
• T. Ichitani, S. Kaneda
  Taiyo Nippon Sanso Corporation, Kawasaki-city Kanagawa Pref.
• T. Kanekiyo
  Hitachi Technologies and Services Co., Ltd., Kandatsu, Tsuchiura
• M. Noguchi
  Mayekawa MFG. Co., Ltd., Moriya
• S. Sakuma, K. Suzuki
  Taiyo Nippon Sanso Higashikanto Corporation, Hitachi-shi, Ibaraki-Perf.

• P. Dauguet
  

• V. Chohan
  
• N. Ali, P. Awale, S. Bahuguna, V. Chauhan, M. Y. Dixit, J. A. Gore, J. John, E. Kandaswamy, A. Kasbekar, P. Kashyap, C. P. Kulkarni, A. Laddha, S. Malhotra, M. Mascarenhas, J. K. Mishra, P. Motiwala, K. Nair, R. Narayanan, S. Padmakumar, A. Pagare, D. Peruppayikkad, S. Raghunathan, S. Rao, D. Roy, S. Sethumadhavan, S. Sharma, S. Shimjith, S. Singh, S. T. Sonnis, P. Surendran, A. Tikaria
  BARC, Mumbai
• U. Bhunia
  DAE/VECC, Calcutta
• G. H. Hemelsoet, F. Pirotte, K. Priestnall, E. Veyrunes
  CERN, Geneva
• A. Kasliwal
  RRCAT, Indore (M. P.)

• G. Moritz
  

• R. I. Saban
  
• R. Alemany-Fernandez, V. Baggiolini, A. Ballarino, E. Barbero-Soto, B. Bellesia, F. Bordry, D. Bozzini, M. P. Casas Lino, V. Chareyre, S. D. Claudet, G.-J. Coelingh, K. Dahlerup-Petersen, R. Denz, M. Gruwe, V. Kain, G. Kirby, M. Koratzinos, R. J. Lauckner, S. L.N. Le Naour, K. H. Mess, F. Millet, V. Montabonnet, D. Nisbet, B. Perea-Solano, M. Pojer, R. Principe, S. Redaelli, A. Rijllart, F. Rodriguez-Mateos, R. Schmidt, L. Serio, A. P. Siemko, M. Solfaroli Camillocci, H. Thiesen, W. Venturini Delsolaro, A. Vergara-Fernandez, A. P. Verweij, M. Zerlauth
  CERN, Geneva
• SF. Feher, R. H. Flora, R. Rabehl
  Fermilab, Batavia, Illinois