Speaker
Rolland Johnson
(Muons, Inc.)
Description
Novel electron gun features are required to enhance the peak and/or average beam brightness by reducing the emittances of electron bunches while allowing the guns to operate at a high repetition rate using laser excitation of the photocathode. The generation of surface acoustical waves (SAW) on piezoelectric substrates is known to produce strong piezoelectric fields that propagate on the surface of the material. These fields can significantly suppress recombination effects and result in enhanced quantum efficiency of photoemission. This new Phase I STTR project is developing the novel use of SAW on photocathodes to control their emittances and improve their efficiency, so that lower-power lasers can generate more intense electron beams having smaller emittances. State-of-the-art computer simulations are being developed for a device that uses Interdigital Transducers (IDT) placed on GaAs photocathode wafers to generate SAW with the required traveling and standing wave properties to demonstrate control of the electron-hole recombination rate. The experimental apparatus to demonstrate suppression of electron-hole recombination as a function of SAW parameters will be designed. Measurements of the quantum efficiency of the photocathode and the beam emittance are planned for Phase II.
Primary author
Rolland Johnson
(Muons, Inc.)
