Analyses of stopping power measurements for 0.90-2.50 MeV protons and deuterons traversing Al2O3 targets

Recently reported measurements of the stopping power of Al2O3 for 0.90-2.50 MeV protons and deuterons have been analyzed in terms of modified Bethe-Bloch theory. Values of the mean excitation energy (I) and Barkas-effect parameter (b) have been extracted from the data, yielding results for I and b, respectively, of 176.8 eV and 0.83 for protons, and of 182.7 eV and 1.02 for deuterons. These values of I exceed the additivity-based value by 32% for proton data and by 36% for deuteron data. Moreover, both extracted values of b lie well below the expected interval of 1.3-1.5. (C) 2000 Elsevier Science B.V. All rights reserved.