Energy loss of MeV protons in diamond: Stopping power and mean ionization energy

The energy loss of protons, in the range between 1.6 MeV and 6 MeV, in a 3.5 μm thick single-crystal diamond membrane was determined by the transmission method. The thickness and surface uniformity of the target were checked by two independent techniques before ion beam irradiation. The stopping power of diamond was evaluated from these data and compared with SRIM Monte Carlo simulations of ion transport, showing a slight overestimate of the simulated values over the experimental stopping powers. In addition, a comparison was made with theoretical calculations based on the Bethe formula to extract the mean ionization potential, I, of carbon atoms in diamond. The obtained I-value was 81 ± 4 eV. A discussion and comparison with results of other authors is given.