MEASUREMENTS OF QUANTUM EFFICIENCY OF MG FILMS PRODUCED BY PULSED LASER ABLATION DEPOSITION FOR APPLICATION TO BRIGHT ELECTRON SOURCES

We report the results of preliminary tests on Mg film photocathodes deposited by pulsed laser ablation deposition on various substrates. A comparison with other deposition techniques is presented. We illustrate briefly the technique of deposition of thick films (up to several microns). Scanning electron microscope analysis of the films before and after laser cleaning has been performed to characterize the changes occurred on the surface. Measurements of the distribution and integrated value of quantum efficiency over the illuminated surface are reported. Plans for the deposition on the back flange of an RF gun are illustrated.