Stopping of Havar, nickel, Kapton, and Mylar for 5–19-MeVO16ions

In order to determine stopping-power values the energy losses of 5.2–22.5-MeV ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}_{}^{\mathrm{n}+}{}_{}{}^{}$ ions in 2.0-μm Havar, 2.8-μm nickel, 10.5-μm Kapton, and 3.8- and 6.9-μm aluminum-layered (40-nm Al) Mylar foils were measured in transmission geometry. Proton energy loss in a backscattering experiment was taken as a measure of film thickness. The measured stopping-power and energy-loss data were compared with calculated predictions obtained by using Bragg’s additivity rule and the Andersen-Ziegler parameters for proton stopping with appropriate scaling for oxygen ions and with experimental values available in the literature. The results for the foils of medium atomic number, Havar and nickel, were found to be similar to calculated values; however, the experimental stopping powers lie 2–4 % above the predicted values between 6 and 14 MeV for the light composite Mylar and Kapton foils. The response of silicon surface-barrier detectors to ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ions was studied in the energy interval 1.5–19 MeV. A distinct nonlinearity was observed at low ion energies.