The potential use of CVD diamond films as a cold cathode material is limited by several factors associated with fast and slow material degradation processes induced by interaction that gives rise to secondary electron (SE) emission. In particular, the negative electron affinity (NEA) loss which has been attributed to Hydrogen detachment from the film surface, happens during ion or electron bombardment and seriously affects SE emission. Using the published results of NEA temperature dependence and connecting them with SE low-energy spectra at different temperatures, we obtained a linear approximation between NEA and surface Hydrogen coverage. The fast ion dose-dependent changes in SE yield are explained by high production rate of radiation defects near their projected range, and the experimentally obtained cross-section of that process is assessed. As a way to improve SE emission durability, we show here the possibility of surface hydrogenation performed at relatively low temperature of 350 degreesC to cause complete hydrogen termination of CVD diamond film surface. Subsequent low dose proton bombardment causes significant decrease in ion induced electron emission (IIEE) coefficient gamma. Repeated 'cold' and 'hot' re-hydrogenation only partially recovers the electron emission properties of the film, implying the existence of residual Boron-defect complexes. (C) 2003 Elsevier B.V. All rights reserved.