Characterization of carbon fiber flocked cathode materials

摘要: Summary form only given. The paper studies the emission characteristics of new cathode materials made carbon fiber flock that have potential to improve electron gun performance. Relativistic beams with high current densities and low temperatures are a prerequisite for successful operation free lasers other sources or coherent radiation use beams. If powers also needed, currents, brightness necessary. These requirements become more stringent shorter wavelength. We examined three different flocks measured emittance using pepper-pot technique. Our anode was 0.38 mm thick stainless steel had single 0.51 pinhole. A 0.038 Al foil coated on downstream side 0.076 coating ZnS used as scintillator. All flocked cathodes diameters 7 microns lengths 0.020", 0.050", 0.100" respectively. Voltages ranged from 80-350 kilovolts. Anode-cathode gap distances varied 0.3 1.2 cm. Current during voltage pulse measured. 130 A/cm/sup 2/ were attained. Turn fields obtained associated V-I characteristics. results compared those standard POCO graphite cathode. substantially lower turn fields, reduced emittance, subsequently much greater brightness.