Ageing of CsI thin film photocathodes induced by UV photons

The degradation of CsI thin film photocathodes (PCs) under UltraViolet (UV) irradiation has been investigated by measuring the photocurrent as well as the absolute Quantum Efficiency (QE) as a function of the accumulated charge density. Force Microscopy (AFM) and UV Photoemission Electron Microscopy (PEEM) have been employed to study the surface morphology and the local QE of polycrystalline CsI thin films and their transformation due to UV irradiation. otoemissive properties of CsI PCs, together with their surface morphology, have been found to be strongly affected by the UV photon ageing.