Statistical analysis of stopping data for protons and alphas in compounds

Using our large data base of experimental stopping powers (more than 150 different compound targets) and our program “Judge”, we compare these data to various published stopping power tables or programs (SRIM-2003, CasP 3.1, PASS and ICRU Report No. 49). We define different energy ranges, and in each we describe the agreement or disagreement by Δ ± σ, where Δ is the average relative difference between data and table, and σ its standard deviation. For SRIM and ICRU, the values Δ are found to be close to zero in most cases. The ICRU table describes the data better than SRIM, but it covers only a comparatively small number of compounds. For He ions in gases, we find a large deviation from SRIM at low energy. By statistical methods, we determine the accuracy with which the deviations from Bragg’s rule are described by Ziegler’s SRIM program.