Ranges of some light ions measured by (<i>p</i>, γ) resonance broadening

Abstract Concentration distributions of 13C, 23Na, 26Mg, 27 Al, and 34S ions implanted in tantalum and of 29Si ions implanted in aluminum have been measured in the energy range 20-100 keV by means of the broadening of a (p, γ) resonance yield curve. Proton energy straggling is included in the analysis in an improved manner. Mean ranges in these polycrystalline targets were found to be larger than those predicted by the Lindhard—Scharff-SchiØtt theory valid for amorphous targets. Range profiles of 27Al in Ta2O5 and of 29Si ions in Al2O3, both amorphous materials, were found to agree well with theory. Relevance to nuclear Doppler-shift attenuation measurements, which are done in polycrystalline targets, is discussed. It is necessary in comparing theory and experiment to take account of the fraction of reflections; the calculated reflection coefficients are given.