A study of high gradient 201 MHz cavities in strong magnetic fields for the MICE experiment

The early sections of the neutrino factory current design co mprise high gradient normal conducting radio-frequency (RF) cavities embedded in high magnetic field. The performance of these cavities is known to degrade with magnetic field; but th e exact nature of the phenomenon, its reproducibility and limitations are not well known. It is pr oposed to make use of the superconducting M1 magnet at CERN and surrounding infrastructure to test thi behaviour. In a first step, which is the object of the present proposal, the 201 MHz RF cavities for the Muon Ionization Cooling Experiment (MICE) will be tested in a systematic way. The ten cavities built at Lawrence Berkeley National Laboratory (LBNL) will be brought to CERN and teste d inside a standalone vacuum vessel, presently under design, to an accelerating gradient of the o rd r of 10 MV/m or more as a function of magnetic field up to 3 T. The rate and spectrum of emission of electrons and x-rays will be measured. The experimental setup and instrumentation are d escribed. The request from CERN amounts to 6 man months of technical manpower and up to 419 kCH F. On a longer time scale these measurements, which are complementary to those perfo rm d at Fermi National Accelerator Laboratory (Fermilab) for the neutrino factory and muon col lider projects, can open the way to systematic studies of normal conducting cavity materials, n ynergy with other projects involving warm RF cavities. Contact: gersende.prior@cern.ch