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Tajima, T.

Paper Title Page
WE5PFP036 Full Temperature Mapping System for Standard 1.3 GHz 9-Cell Elliptical SRF Cavities 2073
 
  • T. Tajima, A.S. Bhatty, A. Canabal, P. Chacon, G.V. Eremeev, R.J. Roybal, J.D. Sedillo
    LANL, Los Alamos, New Mexico
  
 

Funding: DTRA


A temperature mapping system with 4608 100-ohm Allen-Bradley resistors has been built and tested at LANL. With this temperature mapping system we were able to locate lossy regions in the 1.3 GHz 9-cell SRF cavity due to field emission and direct heating. The results of the temperature mapping have been correlated with the inside surface inspection of the cavity and will be shown together with Q-E curves. A brief description of the mapping system and improvements that have been made in the recent months will also be mentioned in the paper.

  
WE5PFP037 SRF Cavity High-Gradient Study at 805 MHz for Proton and Other Applications 2076
 
  • T. Tajima, A.S. Bhatty, P. Chacon, R.L. Edwards, G.V. Eremeev, F.L. Krawczyk, R.J. Roybal, J.D. Sedillo
    LANL, Los Alamos, New Mexico
  • W.A. Clemens, P. Kneisel, R. Manus, R.A. Rimmer, L. Turlington
    JLAB, Newport News, Virginia
  
 

Funding: DTRA


805 MHz elliptical SRF cavities have been used for SNS as the first application for protons. At LANL, an R&D started to explore a capability of getting high-gradient cavities (40-50 MV/m) at this frequency for the future applications such as proton and muon based interrogation testing facility added to the LANSCE accelerator and a power upgrade of the LANSCE accelerator for the fission and fusion material test station. Optimized cell designs for “standard”, “low-loss” and “re-entrant” shapes, cavity test results for “standard” single-cell cavities with temperature mapping as well as surface inspection results will be presented.

  
WE5PFP038 Studies on the Effect of Coating Nb with Thin Layers of Another Superconductor such as NbN and MgB2 2079
 
  • T. Tajima, A. Canabal, G.V. Eremeev
    LANL, Los Alamos, New Mexico
  • I.E. Campisi
    ORNL, Oak Ridge, Tennessee
  • V.A. Dolgashev, S.G. Tantawi
    SLAC, Menlo Park, California
  • X. Xi
    Penn State University, University Park, Pennsylvania
  
 

Funding: DTRA


We are currently testing the effect of coating Nb with a thin layer of another superconductor such as NbN and MgB2. Gurevich’s theory of multi-layered coating predicts an enhancement of the critical magnetic field, giving us hope to increase the achievable accelerating gradient to above 50 MV/m in elliptical cavities. CW test results of 3 GHz Nb single-cell cavities coated with ~100 nm NbN at LANL and 11.4 GHz <1 μs high-power pulsed test results of 2” Nb disk samples coated with ~100 nm MgB2 will be presented.