Electron sputtering of alkali halides a study of its dependence on the beam energy and target temperature

Experimental results are presented on the sputtering of alkali halides by electrons with varying electron energy and different target temperatures. The energy distributions of the emitted alkali and halogen atoms have been measured with a time of flight method. It was found that with increasing temperature the ratio of thermally emitted halogen atoms to non-thermally emitted halogen atoms increases exponentially. We also observed that this ratio is dependent on the electron energy. The experimental results can be understood if it is assumed that the thermal emission of halogen atoms is caused by Vk-centres, created by electron impact A model is described which explains the experimentally observed sputtering yields.