Physico-chemical changes in ion-irradiated KDP

We report on Mev He+ ion-induced physico-chemical changes brought into sing le crystalline potassium dihydrogen phosphate (KDP). Fluence-dependent hydr ogen concentration has been studied by on-line elastic recoil detection ana lysis technique at different temperatures. Room temperature measurements sh ow significant hydrogen loss from the samples, while at low temperature, th ere is no loss of H (at low fluences) or a little loss (at higher fluences) . Structural changes studied by micro-Raman measurements also confirm loss of H followed by amorphization of KDP. Hydrogen depletion from KDP has been addressed in terms of basic ion-solid interaction. A phenomenological mode l has been used which considers ion-induced bond-breaking, diffusion of H r adical, formation of H-2 molecules and its release. (C) 2001 Elsevier Scien ce B.V. All rights reserved.