Secondary electron emission of caesium iodide

Abstract

Experiments were carried out to measure the secondary electron emission yield of thin films of CsI. The vacuum-evaporated layers gave reproducible gain factors of about 20. The energy Epm of the primary electrons at which the gain is maximum is found to be 3·3 keV. The large value of Epm suggests a large escape depth L for secondary electrons. On the basis of experimental results, L is estimated to be 56 nm.