Author: De Silva, S.U.
Paper Title Page
TUPO031 Investigation of the Surface Resistance of Niobium Between 325 MHz and 1300 MHz Using a Coaxial Half-wave Cavity 395
TUOP04   use link to see paper's listing under its alternate paper code  
 
  • H. Park, S.U. De Silva, J.R. Delayen
    ODU, Norfolk, Virginia, USA
 
  The Center for Accelerator Science at Old Dominion University has built a half-wave coaxial cavity (*) to measure the surface resistance of niobium as a function of frequency, temperature, rf field, preparation techniques, over a wide range of frequencies of interest for particle accelerators. The characteristics of the half-wave coaxial cavity provide these information on a same surface. The preliminary results showed clearly the frequency dependence of residual surface resistance (**). After establishing baseline, we have conducted a study of low temperature baking effect on the surface resistance under controlled environment. This paper will describe the details of the test procedure, results and we will explore underlying physics of the phenomenon.
* H. Park et al., MOPB003, Proc. SRF2015, http://jacow.org/
** H. Park et al., THPB080, Proc. SRF2017, http://jacow.org/
 
slides icon Slides TUPO031 [0.966 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO031  
About • paper received ※ 17 September 2018      issue date ※ 18 January 2019  
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TUPO032 First Test Results of Superconducting Twin Axis Cavity for ERL Applications 398
 
  • H. Park, S.U. De Silva, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • A. Hutton, F. Marhauser, H. Park
    JLab, Newport News, Virginia, USA
 
  Superconducting cavities with two beam pipes had been proposed in the past for energy recovery linac applications. The relatively complex geometry of those cavities presented a serious challenge for fabrication and surface processing. Main concerns have now been overcome with the production and successful RF testing of a new elliptical twin-axis cavity proposed by Jefferson Lab and optimized by the Center for Accelerator Science at Old Dominion University in the frame of a DoE accelerator stewardship program. The cavity design provides uniform accelerating or decelerating fields for both beams. This paper describes the cavity design, fabrication experience, and the first cold RF test results and explores potential applications especially for Jefferson Lab s EIC (JLEIC).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO032  
About • paper received ※ 20 September 2018      issue date ※ 18 January 2019  
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TUPO033 Cryogenic Test Results of the SPS Prototype RF-dipole Crabbing Cavity with Higher Order Mode Couplers 402
TUOP05   use link to see paper's listing under its alternate paper code  
 
  • S.U. De Silva, J.R. Delayen, H. Park
    ODU, Norfolk, Virginia, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
  • H. Park
    JLab, Newport News, Virginia, USA
 
  The rf-dipole crabbing cavity planned for the LHC High Luminosity Upgrade is designed to deliver a transverse kick of 3.34 MV; crabbing the proton beam in the horizontal plane. The proton beams of the LHC machine operating at 7 TeV each sets high impedance thresholds on the crabbing cavity systems. The rf-dipole crabbing cavity is designed with a two higher order mode couplers to suppress those HOMs. The first prototype of the HOM couplers are fabricated at Jefferson Lab. This paper reports the cryogenic test results of the HOM couplers with the SPS prototype rf-dipole cavity.  
slides icon Slides TUPO033 [0.859 MB]  
poster icon Poster TUPO033 [1.838 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO033  
About • paper received ※ 17 September 2018      issue date ※ 18 January 2019  
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TUPO035 Determination of the Field-dependence of the Surface Resistance of Superconductors from Cavity Tests 405
TUOP12   use link to see paper's listing under its alternate paper code  
 
  • J.R. Delayen, S.U. De Silva, H. Park
    ODU, Norfolk, Virginia, USA
 
  Cryogenic tests of superconducting cavities yield an average surface resistance as a function of the peak surface magnetic field. An analytical formalism has been developed to extract the actual field dependence of the surface resistance from cavity tests and is applied to coaxial cavities and cavities of more complex geometries.  
slides icon Slides TUPO035 [0.524 MB]  
poster icon Poster TUPO035 [1.002 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO035  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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