Energy loss and straggling of 0.25-2.8 MeV 4He+ ions in gadolinium

The stopping power and energy straggling of 4 He + ions in gadolinium films, evaporated in vacuum, were determined using a backscattering technique in the energy range from 0.25 to 2.8 MeV. The experimental stopping power data were fitted by means of Brice's three parameter formula. The accuracy of the measurements was estimated better than ±3%. The energy loss values agree with the semi empirical calculations of Ziegler for 4 He + ions energies below 1.7 MeV. The energy straggling results are above the theoretical predictions of Bethe-Livingston.