LASER-INDUCED DECONTAMINATION OF POLYCRYSTALLINE W SURFACES - PHOTOLYTIC AND PHOTOTHERMAL EFFECTS

Polycrystalline metallic photocathodes with a covering native oxide la yer were exposed to several wavelengths (213, 266 and 355 nm) of a pic osecond Nd3+-YAG laser. Laser illumination at each wavelength was used to induce oxide film removal and a measurable photoelectric response simultaneously. The change of the photoelectric signal was monitored t hroughout the irradiation process. The evolution of the photoelectric signal was investigated as a function of the applied wavelength and in terpreted in terms of possible surface structural changes. (C) 1998 El sevier Science S.A.