SBIR-STTR Award

Diamond electron amplifiers (DEA) are able to greatly increase the number of electrons emitted from a source while at the same time improving the quality of the amplified electron beam, e.g., producing low emittance and narrow energy spread beams. During Phase I, we propose to 1) perform experiments on a testbed DEA, 2) enhance an existing analytical model of the DEA using data from the testbed DEA, and 3) investigate ways to improve the DEA performance. These results will be used to design a prototype DEA that will be built and demonstrated during Phase II. We will also identify technical risks and methods for addressing them.

Diamond has proven to be a superb material for cathodes. Experiments have demonstrated the ability of diamond wafers to emit over 200 secondary electrons for each primary electron that enters the wafer. These secondary electrons emerge from the diamond with very low energy and very low energy spread, thereby creating a high-quality electron beam (e-beam) with inherently low emittance. Thus, a diamond electron amplifier (DEA) is able to convert a poor quality primary e-beam, such as from a thermionic gun, into a high-quality e-beam with much higher charge than the primary e-beam. Moreover, this e-beam quality can be better than the quality from photocathodes, and does not require a complex UV laser system to drive the process. Diamond has high thermal conductivity, which permits effective cooling to minimize thermal emittance. Unlike bi-alkali photocathodes, diamond cathodes are very robust with the potential for long lifetimes. The primary objective during Phase II is to build and test a DEA electron source prototype that was analyzed and designed during Phase I. The prototype will deliver 100 keV electrons at 3 MHz repetition rate with an average current of 0.3 mA and a peak current of >100 mA. This satisfies the target specifications for the Phase II prototype. In addition, preliminary lifetime data will be obtained.