Energy loss of channeled protons in Al single crystal

Abstract

Two strong resonances in the 27Al(p, α) 24Mg reaction at proton energies 1365 keV 1726 keV respectively are used to investigate the energy loss of protons in an Al single crystal along the channeled direction. The incident proton energy for the 1726 keV resonance has been adjusted at 1735, 1760 and 1786 keV respectively, so that the resonance occurs at depths 0.35, 1.0 and 1.9 μm respectively. The widening of the observed α-peak on the low energy side and the enhancement in the counting rate between the backscattered proton edge and the α-peak for the aligned incidence as compared to the random incidence has clearly shown a wide distribution in the energy loss of protons incident along the 〈110〉 direction. Pile-up effects are suitably taken into account. Quantitative analysis of the distribution in the energy loss is made to show that it may not be very appropriate to use an average energy loss for the particles incident along a crystallographic direction.