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Tajima, T.

Paper Title Page
MOPP121 Full Real-time Temperature Mapping System for 9-cell ILC-type Cavities 841
 
  • A. Canabal, F. L. Krawczyk, R. J. Roybal, J. D. Sedillo, T. Tajima
    LANL, Los Alamos, New Mexico
  • S. Cohen
    Bira, Albuquerque, New Mexico
  • W. Haynes
    Fermilab, Batavia, Illinois
 
  The mapping of outer-wall temperatures during the vertical test of a superconducting radio-frequency (SRF) cavity has been one of the most successful tools in detecting the cavities’ critical hot spots. However, due to the excessive number of sensors needed, no fixed-type temperature mapping (T-mapping) system that covers all cells has been built for 9-cell cavities. With the consensus that T-mapping analysis is needed in order to improve the yield of high-gradient cavities, a system with a reduced data acquisition time and increased temperature sensitivity, compared to rotating-arm systems, has been developed at Los Alamos National Laboratory. The system consists of ~5,000 100 Ω 1/8W Allen-Bradley resistors placed azimuthally every 10 degrees, a similar number of other resistors and diodes that implement the switching scheme, and data acquisition codes written in Labview. The details of the system and first results are presented and discussed.  
MOPP157 Critical Magnetic Field Determination of Superconducting Materials 919
 
  • A. Canabal, T. Tajima
    LANL, Los Alamos, New Mexico
  • V. A. Dolgashev, S. G. Tantawi
    SLAC, Menlo Park, California
  • T. Yamamoto
    UTNL, Ibaraki
 
  Using a 11.4 GHz, 50-MW, <1 μs, pulsed power source and a TE013-like mode copper cavity, we have been measuring critical magnetic fields of superconductors for accelerator cavity applications. This device can eliminate both thermal and field emission effects due to a short pulse and no electric field at the sample surface. A model of the system is presented in this paper along with a discussion of preliminary experimental data.  
MOPP158 Conceptual Design of Automated Systems for SRF Cavity Optical Inspection and Assembly 922
 
  • T. Tajima, A. Canabal, T. A. Harden, R. J. Roybal
    LANL, Los Alamos, New Mexico
 
  The International Linear Collider (ILC) will require ~16,000 Superconducting Radio-Frequency (SRF) cavities at an accelerating gradient of 31.5 MV/m. One of the critical issues that needs to be addressed is the insufficient yield of high-gradient cavities that meet the requirement. This paper describes the design and initial tests of a cavity inner surface optical inspection system. Combined with a full-featured 9-cell cavity temperature mapping system being developed at LANL, we hope to be able to correlate the cavity heating and the surface condition causing it.  
THPP150 LANSCE Vacuum System Refurbishment Plan and Vacuum Alert System Improvements for Predictive Maintenance 3717
 
  • T. Tajima, M. J. Borden, A. Canabal, J. P. Chamberlin, S. Harrison, F. R. Olivas, M. A. Oothoudt
    LANL, Los Alamos, New Mexico
 
  The Los Alamos Neutron Science Center (LANSCE) accelerator, an 800-MeV H+/H- LINAC with a storage ring, has been operated over 30 years since early 1970s. A refurbishment project named LANSCE-R was approved and started in 2007. This paper describes our plan for vacuum system refurbishment as well as an update on the ongoing vacuum email alert system improvement project, which will eventually notify workers of the need for predictive maintenance of particular devices like ion pumps.