PNNL

Abstract

Electronic energy loss is the fundamental mechanism accountable for the response of materials to ions. Helium particles are a product from alpha decay in nuclear waste materials, and helium ions are widely used as projectiles in ion beam analysis. Current work introduces a straightforward approach to determine electronic stopping powers of He ions in Si and SiC over a continuous range of energies. In transmission geometry, the energy loss of He ions in self-supporting stopping foils of Si and SiC is measured using a Time-of-Flight (TOF) set-up. The energy of individual heavy ions prior to impingement on the foil is determined from its TOF data; the exit energy after the stopping foil is essentially measured using the Si detector, for which every channel has been calibrated using TOF data without the stopping foil present. The measured stopping powers demonstrate excellent repeatability of this experimental approach and good reliability as compared with pervious data from the literature and theoretical predictions.