Author: Rowe, A.M.
Paper Title Page
MOP014 Cold Tests of SSR1 Resonators for PXIE 112
 
  • A.I. Sukhanov, M.H. Awida, P. Berrutti, C.M. Ginsburg, T.N. Khabiboulline, O.S. Melnychuk, R.V. Pilipenko, Y.M. Pischalnikov, L. Ristori, A.M. Rowe, D.A. Sergatskov, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Fermilab is currently building the Project X Injector experiment (PXIE). PXIE linac will accelerate 1 mA H beam up to 30 MeV and serve as a testbed for validation of Project X concepts and mitigation of technical risks. A cryomodule of eight superconducting RF Single Spoke Resonators of type 1 (SSR1) cavities operating at 325 MHz is an integral part of PXIE. Ten SSR1 cavities were manufactured in industry and delivered to Fermilab. In this paper we discuss surface processing and tests of bare SSR1 cavities at the Fermilab Vertical Test Stand (VTS). We report on the measured performance parameters of nine cavities achieved during tests.  
 
MOP015 Status of the SRF Development for the Project X 117
 
  • V.P. Yakovlev, T.T. Arkan, M.H. Awida, P. Berrutti, E. Borissov, A.C. Crawford, M.H. Foley, C.M. Ginsburg, I.V. Gonin, A. Grassellino, C.J. Grimm, S.D. Holmes, S. Kazakov, R.D. Kephart, T.N. Khabiboulline, V.A. Lebedev, A. Lunin, M. Merio, S. Nagaitsev, T.H. Nicol, Y.O. Orlov, D. Passarelli, T.J. Peterson, Y.M. Pischalnikov, O.V. Pronitchev, L. Ristori, A.M. Rowe, D.A. Sergatskov, N. Solyak, A.I. Sukhanov, I. Terechkine
    Fermilab, Batavia, USA
 
  Project X is a high intensity proton facility being developed to support a world-leading program of Intensity Frontier physics over the next two decades at Fermilab. The proposed facility is based on the SRF technology and consists of two linacs: CW linac to accelerate beam from 2.1 MeV to 3 GeV and pulsed linac accelerate 5% of the beam up to 8 GeV. In a CW linac five families of SC cavities are used: half-wave resonators (162.5 MHz); single-spoke cavities: SSR1 and SSR2 (325 MHz) and elliptical 5-cell β=0.6 and β=0.9 cavities (650 MHz). Pulsed 3-8 GeV linac linac are based on 9-cell 1.3 GHz cavities. In the paper the basic requirements and the status of development of SC accelerating cavities, auxiliaries (couplers, tuners, etc.) and cryomodules are presented as well as technology challenges caused by their specifics.  
 
MOP036 New Technique and Result of Laser Welded SCRF Cavity Developed at RRCAT 186
 
  • P. Khare, R. Arya, J. Dwivedi, R. Ghosh, G. Gilankar, C. Gupta, P.D. Gupta, A. Jain, S.C. Joshi, G.V. Kane, R. Kaul, P.K. Kush, G. Mundra, S.M. Oak, C.K. Pithawa, P. Ram Sankar, S.B. Roy, V.C. Sahni, R.S. Sandha, P. Shrivastava, B.N. Upadhyay
    RRCAT, Indore (M.P.), India
  • C.A. Cooper, C.M. Ginsburg, A. Grassellino, C.S. Mishra, A.M. Rowe
    Fermilab, Batavia, USA
 
  A new technique to fabricate SCRF cavities with the help of laser welding process has been developed at Raja Ramanna Centre for Advanced Technology RRCAT), Indore, Department of Atomic Energy, India. In this technique, a pulsed Nd:YAG laser has been used and welding was performed in inert gas environment, in a specially designed welding rig. The advantages of this technique are reduced cost, small heat affected zone, no necessity to weld in vacuum and enhanced rate of production. The paper describes the technique and fabrication method of a single-cell 1.3 GHz SCRF cavity which was fabricated at RRCAT with this new technique. It also discusses the test result of this cavity which was processed and tested at Fermilab. The cavity reached an Eacc of 17MV/m with a Q0 of 1.4 E +10 at 2K. The cavity is being barrel polished for further improvement.  
 
MOP073 IHEP 1.3 GHz Low Loss Large Grain 9-cell Cavity Fabrication, Processing and Test 305
 
  • J.Y. Zhai, J. Gao, S. Jin, Z.Q. Li, Y. Liu, Z.C. Liu, Z.H. Mi, X.H. Peng, T.X. Zhao, H.J. Zheng
    IHEP, Beijing, People's Republic of China
  • C.A. Cooper, C.M. Ginsburg, T.N. Khabiboulline, A.M. Rowe, D.A. Sergatskov
    Fermilab, Batavia, USA
  • J.X. Wang, H. Yu, H. Yuan
    BIAM, Beijing, People's Republic of China
 
  The combination of the low-loss shape and large grain niobium material is expected to be the possible way to achieve higher gradient and lower cost for ILC 9-cell cavities, and will be essential for the ILC 1 TeV upgrade. As the key component of the “IHEP 1.3 GHz SRF Accelerating Unit Project”, a low-loss shape 9-cell cavity with full end groups using Ningxia large grain niobium (IHEP-02) was fabricated at IHEP in 2012. The cavity was processed (CBP and EP) and tested at FNAL. The cavity processing,test performance and gradient limitation is reported in this paper. We will weld the helium vessel, assemble the magnetic shield and install the cavity to IHEP ILC-TC1 cryomodule.  
 
TUIOC02 Bipolar EP: Electropolishing without Fluorine in a Water Based Electrolyte 404
 
  • A.M. Rowe, A. Grassellino
    Fermilab, Batavia, USA
  • T.D. Hall, M.E. Inman, S.T. Snyder, E.J. Taylor
    Faraday Technology, Inc., Clayton, USA
 
  Funding: Operated by Fermi Research Alliance, LLC under contract No. De-AC02-07CH11359 with the United States Department of Energy
For more than thirty years, preparing superconducting RF cavities for high performance has required the use of dangerous and ecologically damaging chemicals. Reducing the personnel and environmental risks associated with using these chemicals is a priority at Fermilab. Therefore, Fermilab pursued a project to adapt a non-hazardous and relatively benign bipolar electropolishing technique to SRF cavities that Faraday Technology, Inc. developed. Faraday initially developed this electropolishing technique to polish metal alloys used in automotive and semiconductor components as well as medical devices and implants. By modifying the cathodic/anodic interaction via a pulse forward/pulse reverse technique, Fermilab and Faraday Technology demonstrate the capability to polish 1.3 GHz single-cell cavities utilizing an aqueous 10% sulfuric acid electrolyte. We present the development of bipolar EP for single-cell 1.3 GHz cavities and show the results from vertical tests achieving gradients greater than 40 MV/m.
 
slides icon Slides TUIOC02 [1.251 MB]  
 
TUP030
Elimination of post annealing chemistry: a route to high Q cavities and processing simplification  
 
  • A. Grassellino, A.C. Crawford, R.D. Kephart, O.S. Melnychuk, A. Romanenko, A.M. Rowe, D.A. Sergatskov, M. Wong
    Fermilab, Batavia, USA
  • M. Checchin
    INFN/LNL, Legnaro (PD), Italy
  • Y. Trenikhina
    IIT, Chicago, USA
 
  Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
We investigate the effect of high temperature treatments followed by only high-pressure water rinse (HPR) of superconducting radio frequency (SRF) niobium cavities. The objective is to provide a cost effective alternative to the typical cavity processing sequence, by eliminating the material removal step post furnace treatment while preserving or improving the RF performance. The studies have been conducted in the temperature range 800-1000C for different conditions of the starting substrate: large grain and fine grain, electro-polished (EP) and centrifugal barrel polished (CBP) to mirror finish. An interesting effect of the grain size on the performances is found. Cavity results and samples characterization show that furnace contaminants cause poor cavity performance, and a practical solution is found to prevent surface contamination. Extraordinary values of residual resistances ~ 1 nOhm and below are then consistently achieved for the contamination-free cavities. We explore the addition of a small partial pressure of gas during the anneal to further increase the cavity quality factor by reducing the BCS resistance.
 
 
TUP050
R&D Program for 650 MHz Niobium Cavities for Project X  
 
  • A. Grassellino, A.C. Crawford, C.M. Ginsburg, R.D. Kephart, T.N. Khabiboulline, O.S. Melnychuk, A. Romanenko, A.M. Rowe, D.A. Sergatskov, A.I. Sukhanov, M. Wong, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
We report the first test results of several 650 MHz single cell niobium cavities processed at Fermilab. The target for the 5-cell 650 MHz cavities for Project X is CW operation at magnetic peak field ~ 60-70 mT, making high quality factors at medium accelerating fields the main goal of the surface processing R&D. We will discuss how the performance vary with the different surface processing and parameters/criteria of choice for the final surface preparation sequence.
 
 
TUP054 Electropolishing of Niobium SRF Cavities in Low Viscosity Aqueous Electrolytes Without Hydrofluoric Acid 540
 
  • E.J. Taylor, T.D. Hall, M.E. Inman, S.T. Snyder
    Faraday Technology, Inc., Clayton, USA
  • A.M. Rowe
    Fermilab, Batavia, USA
 
  Funding: U.S. DOE Purchase order No. 594128
Electropolishing of niobium materials and cavities is conventionally conducted in high viscosity electrolytes consisting of concentrated sulfuric and hydrofluoric acid. The use of these dangerous and ecologically damaging chemicals requires careful attention to safety protocol to avoid harmful worker exposure and environmental damage. In this poster we present an approach based on bipolar voltage fields enabling the use of low viscosity water based electrolytes without hydrofluoric acid for electropolishing of niobium materials. The subtleties of the bipolar electropolishing process vis-a-vis conventional electropolishing will be presented.
 
 
TUP060 Acid Free Extended Mechanical Polishing R&D 564
 
  • C.A. Cooper, A.C. Crawford, C.M. Ginsburg, A. Grassellino, R.D. Kephart, O.S. Melnychuk, A. Romanenko, A.M. Rowe, D.A. Sergatskov
    Fermilab, Batavia, USA
 
  We report the progress in the development of a centrifugal barrel polishing recipe which can lead to standard cavity performance without the need of any chemical treatments. Q ~ 1010 at 20 MV/m and gradients above 35 MV/m have already been demonstrated for cavities whose preparation sequence was CBP, degassing and no subsequent chemical treatments. Results of studies on the effect of different CBP media on RF performance will be reported, including full body T-map showing the distribution of RF losses.  
 
THP030 Superconducting RF Cavity Development With UK Industry 966
 
  • A.E. Wheelhouse, R.K. Buckley, L.S. Cowie, P. Goudket, A.R. Goulden, P.A. McIntosh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • C.A. Cooper, C.M. Ginsburg, A. Grassellino, O.S. Melnychuk, A.M. Rowe, D.A. Sergatskov
    Fermilab, Batavia, USA
  • J.R. Everard, N. Shakespeare
    Shakespeare Engineering, South Woodham Ferrers, Essex, United Kingdom
 
  As part of a continuing STFC Innovations Partnership Scheme (IPS) grant, in support of enabling UK industry to address the large potential market for superconducting RF structures Daresbury Laboratory and Shakespeare Engineering Ltd are developing the capability to fabricate, process and test a niobium 9-cell 1.3 GHz superconducting RF cavity. A single-cell cavity fabricated under this grant was surface processed and tested at Fermilab, and achieved an accelerating gradient in excess of 40 MV/m at an unloaded quality factor in excess of 1.0 x 1010. This paper presents the results of the single-cell cavity testing and discusses the progress made to date in the development of the design and manufacture of a 9-cell niobium cavity, which Shakespeare Engineering Ltd will fabricate and which is anticipated to be qualified in 2014.  
 
FRIOB02 Development and Performance of 325 MHz Single Spoke Resonators for Project X 1187
 
  • L. Ristori, M.H. Awida, P. Berrutti, C.M. Ginsburg, I.V. Gonin, T.N. Khabiboulline, M. Merio, T.H. Nicol, D. Passarelli, A.M. Rowe, D.A. Sergatskov, A.I. Sukhanov, 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.
Two types of single spoke resonators will be utilized for beam-acceleration in the low energy part of the Project X linac. SSR1 and SSR2 operate at 325 MHz and at an optimal beta of 0.22 and 0.51 respectively. After the initial phase of prototyping, a production run of 10 SSR1 resonators was recently completed in US industry. The qualification of this group of resonators in the Fermilab VTS is proceeding successfully and nearly complete. The first qualified resonator has been outfitted with a Stainless Steel helium vessel. Preliminary test results for the first jacketed SSR1 are presented. The first RF power couplers were ordered, the design of the double-lever tuning mechanism is almost complete.
 
slides icon Slides FRIOB02 [8.800 MB]