Energy loss of 14N ions in Ni, Ag, and Cu and the lifetimes of the states at 2.3 and 3.9 MeV in 14N.

Abstract

The energy loss of /sup 14/N ions in Ni, Ag, and Cu has been investigated via the inverted Doppler-shift attenuation technique in the energy range up to 3.1 MeV. Excited /sup 14/N nuclei were produced in the reaction /sup 12/C(/sup 3/He,p) /sup 14/N/sup */, and energy-loss information was obtained from the analysis of the Doppler-broadened 2.313-MeV ..gamma..-ray line, observed with a Ge(Li) detector. This analysis also yielded the lifetimes of the levels at 2.3 and 3.9 MeV in /sup 14/N, which were determined to be 97.7 +- 5.5 and 5.6 +- 1.1 fs, respectively, in reasonable agreement with previous measurements and theoretical calculations. The stopping cross sections obtained for all three stopping media are compared with existing theoretical calculations, especially with regard to the oscillations with the atomic number of the stopping medium.