L shell ionisation of medium and heavy elements by 1.2–3.0 Mev incident deuterons

Abstract

L subshell ionisation cross sections, σ exp L i have been measured for a number of selected elements with atomic number 66 ⩽ Z ⩽ 83. The L shell X-rays, produced by bombarding carbon backed thin targets ∼ 50 μg/cm 2 thick with deuterons in the energy range 1.2–3 MeV, were detected using a Si(Li) detector. The cross sections were obtained from the measured X-ray yields, the experimentally determined target thicknesses and detector efficiency. The cross sections have been compared with the ECPSSR theory by expressing graphically the ratio σ exp Li σ ECPSSR Li as a function of the corrected reduced velocity parameter ξ R L i Discrepancies of up to 50% were observed for σ exp L i which appear to be Z dependent. In all cases the theory underpredicts σ exp L2 by 10–60%, with the larger deviations occurring at lower reduced velocity parameters. The σ exp L3 data are in reasonable agreement with the ECPSSR predictions. Possible reasons for these discrepancies are discussed.