Stopping Power of Al, Cu, Ag, Au, Pb, and U for 5—18-MeV Protons and Deuterons

Abstract

The stopping power of Al, Cu, Ag, and Au has been measured for 9---18-MeV protons and deuterons in order to extend earlier Ris\o measurements covering the energy range 5---12 MeV. Furthermore, the stopping power of Pb and U was measured in the energy range 5---18 MeV. The standard deviation of the new data for the first four materials is 0.4%, while for Pb and U it is 0.6% and 0.8%, respectively. The mean excitation potential for copper is deduced to be 319.8 \ifmmode\pm\else\textpm\fi{} 3.2 eV, in good agreement with our earlier results. Excitation potentials for Ag, Au, U, and Pb are also extracted from the data. The results for the Pb and U support the view that the ratio between the mean excitation potential and the atomic number (the Bloch constant) is an oscillatory function of the atomic number.