MICROANALYSIS SURFACE STUDIES AND PHOTOEMISSION PROPERTIES OF CSI PHOTOCATHODES

We present recent results of the study of surface properties and quant um efficiency (QE) of CsI photocathodes prepared on various substrates . Microanalysis methods provide laterally resolved surface morphology and chemical composition of the photoemissive film. Integral measureme nts of the QE of CsI were done with a monochromator system and a RICH device. It was shown that CsI films deposited on large area Ni- or Ni- Au-coated printed circuit electrodes have a uniform crystalline struct ure and an average QE close to that reached on polished stainless stee l. The films have a good stability in air over periods of Ih. On a mic roscopic scale of 3-30 mu m, the films exhibit nonuniform emission pro perties correlated with variations in the chemical composition.