Measurement of the Magnetic and Thermal Characteristics of Ferrites for a 300 kHz AC Dipole for the Mu2e Experiment

A charged lepton flavor violation experiment, Mu2e, is planned at Fermilab, searching for muon to electron conversions with an unprecedented sensitivity, better than 6 ?? 10^-17 at 90% CL. To achieve such sensitivity the incoming beam must be highly suppressed during the window for detecting the conversion a muon into an electron. One proposal for beam extinction is based on a collimator with two dipoles running in a resonant circuit at ~300 kHz synchronized to the bunch spacing. An appropriate choice of the ferrite material for the magnet yoke is critical to ensuring the reliable operation of such a high frequency dipole over the life of the experiment. In this paper, we present the results of the thermal and magnetic measurements of the selected ferrite material, including the field non-linearity effects and power losses. Some dimensional optimization of the ferrite bricks is also discussed.