Heat enhancement of the photoyield from CsI, NaI and CuI photocathodes

We revise the quantum efficiency of NaI and CuI reflective photocathodes. We have shown that the photoyield from NaI and CuI can be considerably enhanced by a post-evaporation heat treatment, similarly to that observed before for the CsI photocathode. We discuss possible reasons for the heat enhancement.