Photocathode device that replenishes photoemissive coating

A photocathode device, comprising:

• a first chamber comprising a porous cathode substrate, the porous cathode substrate comprising an outer wall surface and an inner wall surface;
• a photoemissive coating on the outer wall surface of the porous cathode substrate;
• a second chamber comprising a replenishment material, the second chamber separated from the first chamber by a first wall, the first wall comprising an orifice that allows a vapor of the replenishment material to move into the first chamber from the second chamber;
• and
• a linear actuator system configured to convert the replenishment material into vapor, the linear actuator system comprising:
• a rod,
• a compressive element configured to urge the rod into a position where a tip of the rod is forced into the orifice,
• a first piezo-electrode and a second piezo-electrode configured to create a voltage potential therebetween, and
• a piezo linear motor configured to oscillate the rod back and forth when the voltage potential is created between the first piezo-electrode and the second piezo-electrode, wherein
• at least some of the replenishment material vapor travel through the inner wall surface of the porous cathode substrate to the outer wall surface of the porous cathode substrate, thereby replenishing the photoemissive coating.

A photocathode device, comprising:

• a first chamber comprising a porous cathode substrate, the porous cathode substrate comprising an outer wall surface and an inner wall surface;
• a photoemissive coating on the outer wall surface of the porous cathode substrate;
• a second chamber separated from the first chamber by a first wall, the first wall comprising an orifice that allows ions of the replenishment material to move into the first chamber from the second chamber;
• and
• a linear actuator system configured to convert the replenishment material into ions, the linear actuator system comprising:
• a rod comprising a cartridge at an end thereof, the cartridge comprising the replenishment material and inserted into the second chamber such that the second chamber comprises the replenishment material, and
• a metallic grid spanning the orifice, wherein
• the metallic grid provides a difference in electric potential with respect to the rod such that ions are generated from the replenishment material in the cartridge of the rod, and
• at least some of the replenishment material ions travel through the inner wall surface of the porous cathode substrate to the outer wall surface of the porous cathode substrate, thereby replenishing the photoemissive coating.