a high power diode includes a cathode for emitting a primary electron discharge , an anode , and a porous dielectric layer , e . g . a honeycomb ceramic , positioned between the cathode and the anode for receiving the primary electron discharge and emitting a secondary electron discharge . the diode can operate at voltages 50 kv and higher while generating an electron beam with a uniform current density in the range from 1 a / cm 2 to & gt ; 10 ka / cm 2 throughout the area of the cathode . it is capable of repetitively pulsed operation at a few hz with pulse duration from a few nanoseconds to more than a microseconds , while the total number of pulses can be & gt ; 10 7 pulses . the diode generates minimal out - gassing or debris , i . e . with minimal ablation , providing a greater diode lifetime , and can operate in a high vacuum environment of 10 − 4 torr . the high power diode is useful in many applications requiring a high current electron beam . exemplary applications include x - ray photography of large samples , polymerization processes , sterilization of biological and chemical agents , irradiation of food , and as a pump for lasers , e . g . excimer lasers such as krypton fluorine lasers .