Stopping power measurements of 20-180 keV ¹H and ⁴He in Indium Phosphide using thick target backscattering

Abstract

The stopping power of InP for 20-180 keV 1H and 4He was determined by measuring the absolute backscattering yield of thick InP targets. Several nonideal aspects of surface barrier detectors were observed which should be accounted for when making low to medium energy backscattering yield measurements. These are: non-Gaussian detector resolution, nonlinear detector energy calibration, and ion reflection in the detector Au window. The present 1H in InP stopping cross section measurements are in good agreement with those recently obtained by Khodyrev et al. using a relative, bulk yield, single spectrum approach. The 4He in InP stopping cross section measurements were found to be velocity proportional below 30 keV/amu. The estimated standard error of the measurements is + 7% at 20 keV and + 4% at 180 keV.