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Tollestrup, A.V.

Paper Title Page
WEPE066 Beam Test of a High Pressure Cavity for a Muon Collider 3494
 
  • M. Chung, A. Jansson, A. Moretti, A.V. Tollestrup, K. Yonehara
    Fermilab, Batavia
  • A. Kurup
    Imperial College of Science and Technology, Department of Physics, London
  
 

To demon­strate the fea­si­bil­i­ty of a high pres­sure RF cav­i­ty for use in the cool­ing chan­nel of a muon col­lid­er, an ex­per­i­men­tal setup that uti­lizes 400-MeV Fer­mi­lab linac pro­ton beam has been de­vel­oped. In this paper, we de­scribe the beam di­ag­nos­tics and the col­li­ma­tor sys­tem for the ex­per­i­ment, and re­port the ini­tial re­sults of the beam com­mis­sion­ing. The tran­sient re­sponse of the cav­i­ty to the beam is mea­sured by the elec­tric and mag­net­ic pick­up probes, and the beam-gas in­ter­ac­tion is mon­i­tored by the op­ti­cal di­ag­nos­tic sys­tem com­posed of a spec­trom­e­ter and two PMTs.

  
WEPE067 Beam-induced Electron Loading Effects in High Pressure Cavities for a Muon Collider 3497
 
  • M. Chung, A. Jansson, A.V. Tollestrup, K. Yonehara
    Fermilab, Batavia
  • Z. Insepov
    ANL, Argonne
  
 

Ion­iza­tion cool­ing is a crit­i­cal build­ing block for the re­al­iza­tion of a muon col­lid­er. To sup­press break­down in the pres­ence of the ex­ter­nal mag­net­ic field, an idea of using an RF cav­i­ty filled with high pres­sure hy­dro­gen gas is being con­sid­ered for the cool­ing chan­nel de­sign. In the high pres­sure RF cav­i­ty, ion­iza­tion en­er­gy loss and lon­gi­tu­di­nal mo­men­tum re­cov­ery can be achieved si­mul­ta­ne­ous­ly. One pos­si­ble prob­lem ex­pect­ed in the high pres­sure RF cav­i­ty is, how­ev­er, the dis­si­pa­tion of sig­nif­i­cant RF power through the elec­trons ac­cu­mu­lat­ed in­side the cav­i­ty. The elec­trons are gen­er­at­ed from the beam-in­duced ion­iza­tion of the high pres­sure gas. To char­ac­ter­ize this detri­men­tal load­ing ef­fect, we de­vel­op a sim­pli­fied model that re­lates the elec­tron den­si­ty evo­lu­tion and the ob­served pick­up volt­age sig­nal in the cav­i­ty, with con­sid­er­a­tion of sev­er­al key molec­u­lar pro­cess­es such as the for­ma­tion of the poly­atom­ic molecules and ions, ex­ci­ta­tion, re­com­bi­na­tion and elec­tron at­tach­ment. This model is ex­pect­ed to be com­pared with the ac­tu­al beam test of the cav­i­ty in the Mu­Cool Test Area (MTA) of Fer­mi­lab.

  
WEPE069 Study of Electron Swarm in High Pressure Hydrogen Gas Filled RF Cavities 3503
 
  • K. Yonehara, M. Chung, A. Jansson, A. Moretti, M. Popovic, A.V. Tollestrup
    Fermilab, Batavia
  • M. Alsharo'a, R.P. Johnson, M. Notani
    Muons, Inc, Batavia
  • D. Huang
    IIT, Chicago, Illinois
  • Z. Insepov
    ANL, Argonne
  • T. Oka, H. Wang
    University of Chicago, Chicago, Illinois
  • D. Rose
    Voss Scientific, Albuquerque, New Mexico
  
 

A high pres­sur­iz­ing hy­dro­gen gas filled RF cav­i­ty has a great po­ten­tial to apply for muon col­lid­ers. It gen­er­ates high elec­tric field gra­di­ents in strong mag­net­ic fields with var­i­ous con­di­tions. As the re­main­ing demon­stra­tion, it must work under high ra­di­a­tion con­di­tions. A high in­ten­si­ty muon beam will gen­er­ate a beam-in­duced elec­tron swarm via the ion­iza­tion pro­cess in the cav­i­ty. A large amount of RF power will be con­sumed into the swarm. We show the re­cent non-beam test and dis­cuss the elec­tron swarm dy­nam­ics which plays a key role to de­vel­op a high pres­sure RF cav­i­ty.