Author: Pan, P.
Paper Title Page
WEPFI092 Multipacting Simulation of the MICE 201 MHz RF Cavity 2914
  • T.H. Luo, D.J. Summers
    UMiss, University, Mississippi, USA
  • D.L. Bowring, A.J. DeMello, D. Li, P. Pan, S.P. Virostek
    LBNL, Berkeley, California, USA
  • L. Ge
    SLAC, Menlo Park, California, USA
  The international Muon Ionization Cooling Experiment (MICE) aims to demonstrate transverse cooling of muon beams by ionization. The MICE ionization cooling channel requires eight 201-MHz normal conducting RF cavities to compensate for the longitudinal beam energy loss in the cooling channel. Multipacting is a resonant electron discharge produced by the synchronization of emitted electrons with the RF fields, which can cause breakdown at high power RF operation. In this paper, we present the study of the multipacting effect in the MICE 201 MHz cavities with the SLAC ACE3P code. The simulation is carried out in the cavity body, the RF coupler region, and the coaxial waveguide, with the external magnetic field from the Coupling Coil. We will identify potential RF breakdowns due to multipacting and propose a solution to suppress them.  
THPME048 Assembly and Test of a Modified Spectrometer Solenoid for MICE 3621
  • S.P. Virostek, D. Li, P. Pan, S. Prestemon
    LBNL, Berkeley, California, USA
  • R. Preece
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  Funding: This work is supported by the Office of Science, US-DOE under DOE contract DE-AC02-05CH11231.
The MICE superconducting spectrometer solenoids have been modified and rebuilt as a result of the testing done in 2008, 2009 and 2010. The number of two-stage cryocoolers was increased from three in 2009 to five in the modified magnet. The new shield for the spectrometer solenoid is fabricated primarily from 1100-O aluminum instead of 6061-T6 aluminum used in the former versions of the magnet. The thermal connection between the shield and the first-stage of the cold heads has been improved to reduce the temperature drop between the shield and the coolers. As a result of these changes, the first-stage temperatures for the coolers are below 45K, which resulted in an increase in the refrigeration generated by the cooler second stages. The quench protection system has been altered in order to provide additional protection to the magnet in the event of a lead failure between the magnet power supply and the magnet coils. The quality of the shield and cold mass MLI wrap has also been improved. Details of the modifications and test results demonstrating improved magnet performance are presented in this paper.