Abstract

High secondary electron emission (SEE) has been observed from CVD grown diamond. Values of the secondary electron coefficient (σ) have been measured between 10 and 20 from as-received (hydrogen terminated) diamond films, but the emission was unstable under continuous exposure to electrons and σ decreased with a fluence dependence due to electron induced hydrogen desorption from the diamond surface. It was observed recently, that activation of a CsI coated diamond surface by electron exposure left a thin Cs layer (1 to several monolayers) which stabilized the secondary emission to values of σ = 20 - 35 at 1500 eV, independent of the primary current density. These electron beam activated-alkali terminated (EBAAT) diamond films are being used as dynodes in an electron multiplier assembly. This assembly has been tested previously using hydrogen terminated diamond dynodes operated in a hydrogen environment.