PHOTOEMISSION-STUDIES WITH BARIUM AND LAB6 PHOTOCATHODES AND POLARIZED LASER-LIGHT

Photoemission measurements with barium and single crystal LaB6 photoca thodes are reported. The barium cathode is prepared by depositing a ba rium thin film onto a copper substrate. The LaB6 cathode is a single c rystal cut in the (100) plane. Radiation from a nitrogen laser (337 nm , 10 ns) is polarized and strikes the cathode surface at variable angl es. An electron quantum yield as high as 2x10(-3) is observed with bar ium. The dependence of the quantum yield on the beam polarization and angle of incidence is investigated. The results indicate that higher q uantum yields are achieved when the angles of polarization and inciden ce are such as to minimize the reflection coefficient. (C) 1994 Americ an Institute of Physics.