ELECTRONIC STOPPING CROSS SECTIONS FOR H-1 AND HE-4 PARTICLES IN CR, MN, CO, NI, AND CU AT ENERGIES NEAR 100 KEV

Electronic stopping cross sections have been measured for 30- to 140-keV H1 and 50- to 120-keV He4 particles in Cr, Mn, Fe, Co, Ni, and Cu (24≤Z2≤29). In this Z2 region the cross sections at a given energy show a steady decrease with increasing Z2, thus confirming and extending earlier observations by others. The combined data show a dependence on Z2 which is markedly similar to the periodic dependence of electronic stopping cross sections on the Z of the projectile. The measurements were made utilizing high-resolution solid-state-detector spectra of the particles backscattered from thin films of the target materials evaporated on thick substrates. The probable error of the stopping-cross-section measurements is 3%. © 1969 The American Physical Society.