Novel cathode for long pulse electron beams

Summary form only given. Experiments have been carried out on salt-coated, carbon-fiber-based cathodes at voltages in the 8-160 kV range. Data on the operating performance of this salt cathode have been obtained, including streak photographs showing the uniformity of the electron beam emission. Streak-photo data indicates that emission spreads rapidly to the nearby glyptol-coated corona busing-a low-field enhanced, nominally nonemitting surface. It is speculated that secondary emission driven by UV light from the cathode plasma may be responsible for this anomalous effect. When the emitting surface was recessed to eliminate line-of-sight to portions of the corona bushing, the effective diameter of the emitting surface was observed to contract. Although preliminary, these data indicate that UV is an important mechanism in promoting the emission process.