• 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.

• A.D. Bross, M. Chung, A. Jansson, A. Moretti, K. Yonehara
  Fermilab, Batavia
• D. Huang, Y. Torun
  IIT, Chicago, Illinois
• D. Li
  LBNL, Berkeley, California
• J. Norem
  ANL, Argonne
• R. B. Palmer, D. Stratakis
  BNL, Upton, Long Island, New York
• R.A. Rimmer
  JLAB, Newport News, Virginia

TThe MuCool RF Program focuses on the study of normal conducting RF structures operating in high magnetic field for applications in muon ionization cooling for Neutrino Factories and Muon Colliders. This paper will give an overview of the program, which will include a description of the test facility and its capabilities, the current test program, and the status of a cavity that can be rotated in the magnetic field which allows for a more detailed study of the maximum stable operating gradient vs. magnetic field strength and angle.

• Y. Torun, D. Huang
  IIT, Chicago, Illinois
• A.D. Bross, M. Chung, A. Jansson, A. Kurup, J.R. Misek, A. Moretti
  Fermilab, Batavia
• J. Norem
  ANL, Argonne

Muon cooling requires high-gradient normal conducting cavities operating in multi-Tesla magnetic fields for muon beam focusing in an ionization cooling channel. Recent experience with an 805-MHz pillbox cavity at the Fermilab MuCool Test Area has shown significant drop in accelerating field performance for the case of parallel electric and magnetic fields. It has been suggested that having the magnetic field perpendicular to the electric field should provide magnetic insulation and suppress breakdown. An 805-MHz Cu rectangular box cavity was built for testing with the fields perpendicular. It was mounted on an adjustable support to vary the angle between the rf electric and external magnetic field. We report on design and operation of the rectangular box cavity.

• T.J. Roberts, K.B. Beard
  Muons, Inc, Batavia
• S. Ahmed, D. Huang, D.M. Kaplan, L.K. Spentzouris
  Illinois Institute of Technology, Chicago, Illinois

The G4beamline program* is a useful and steadily improving tool to quickly and easily model beam lines and experimental equipment without user programming. It has both graphical and command-line user interfaces. Unlike most accelerator physics codes, it easily handles a wide range of materials and fields, being particularly well suited for the study of muon and neutrino facilities. As it is based on the Geant4 toolkit**, G4beamline includes most of what is known about the interactions of particles with matter. We are continuing the development of G4beamline to facilitate its use by a larger set of beam line and accelerator developers. A major new feature is the calculation of space-charge effects. G4beamline is open source and freely available at: http://g4beamline.muonsinc.com

* http://g4beamline.muonsinc.com
** http://geant4.cern.ch