Stopping powers of Sn and Pb for 3.0–8.5 MeV protons

Abstract

Stopping powers of Sn and Pb for 3.0–8.5 MeV protons have been measured with a silicon surface barrier detector. Since a foil of pure metallic Pb was hard to handle, about 5% Sn was mixed in the Pb foils used. Assuming that Bragg's additivity rule was applicable and using stopping power data of Sn, we obtained stopping powers of Pb. Analyzing the experimental results with the Bethe-Bloch formula including the Z 3 1 correction, we deduced I-values of Sn and Pb. In order to investigate the influence of the adopted corrections on the extracted I-values, we used the following two sets of corrections; (1) Bonderup's shell correction, the Z 3 1 correction of Ashley, Ritchie and Brandt, and the Bloch correction. (2) The empirical “shell correction” of Andersen and Ziegler which gave the sum of these corrections. Although both sets of corrections gave good reproductions of the experimental results, better fits were obtained with the former corrections for Sn and with the latter corrections for Pb. For Sn the extracted I-values were in excellent agreement, while for Pb agreement was not so good.