A thin layer of ZnO0.3 deposited on a SiO2 glass substrate was irradiated w
ith a 2 MeV alpha microbeam. The disappearance of ZnO0.3 in the neighbourho
od of the beam was registered in situ. We quantitatively account for this b
ehaviour in the framework of a very simple vaporisation model based both up
on the local temperature increase resulting from the microbeam itself and u
pon the variation of the Zn vapour pressure with the local temperature. Oth
er possible explanations are briefly discussed. (C) 1999 Elsevier Science B
.V. All rights reserved.