A detailed experimental study has been made of suspected multipactor discharge in a klystron input cavity in the presence of an axial magneticfield.. The existence of the discharge was detected by changes in the return loss at the input coupler. This method does not require any modification of the cavity. Discharges appeared to take place over a range of input powers from 5 W up to 100 W for two distinct ranges of the magnetic field. Tests with a hand-heldpermanent magnet suggested that the discharges are located around the equator of the cavity. Comparison with theory confirmed that the lower band is probably a single-surface crossed-field multipactor discharge. Investigation of the upper band is continuing.
7th IEEE International Vacuum Electronics Conference (IVEC)/6th IEEE International Vacuum Electron Sources Conference (IVESC), Monterey, CA, APR 25-27, 2006