Stopping-powers and straggling of N-15 ions for nuclear reaction analysis at 6.385 MeV

Stopping-powers and straggling has been measured for N-15 incident ions at 6.4 MeV using the well known H-1(N-15,alpha gamma)C-12 resonant nuclear reaction at 6.385 MeV, Samples have been prepared using electron beam evaporation of various elements on H terminated silicon substrates under UHV conditions with high layer quality. The H monolayer remains stable at the silicon substrate during evaporation and ion irradiation. The layer thicknesses were ranging from 500 to 2000 Angstrom. At this thickness range the energy straggling is between 15 and 40 keV (sigma) and is the main contribution to the measured width of the H profile. Surface roughness, interface quality and Doppler broadening are negligible. The measured H profiles were fitted with a Gaussian normal distribution function. In the case of target materials, as e.g. Nb, which incorporate H easily, the layers were H charged and an integrated Gauss function was used for fitting. The stopping-powers and straggling were compared with ZBL data for electronic stopping, Bohr straggling and TRIM simulations for nuclear stopping and straggling and with former experimental data obtained with same method, The data for stopping-power and straggling showed remarkable differences to former measurements.