Z1 stopping power oscillation in the nuclear stopping regime as obtained by time-of-flight spectroscopy of heavy ions in hydrogen

Abstract

The time-of-flight technique is used to measure the specific energy loss of heavy ions (49 ⩽ Z 1 ⩽ 65) in hydrogen in the nuclear stopping regime. The derived stopping power exhibits a characteristic oscillation with the atomic number of the projectile. The oscillation amplitude increases from 5% at ϵ = 0.1 to 20% at ϵ = 0.02 (ϵ is the reduced energy). The results are compared with range measurements, atomic size parameters and theoretical predictions. They can be interpreted either by a considerable shell effect of the nuclear stopping or by a strong variation of the correction factor c k for the Lindhard-Scharff constant of electronic stopping.