Absolute-scale measurement of compton backscattering in germanium at 105.3keV

The differential cross section d(2)sigma /dE d Omega was measured at an inc ident photon energy of 105.3 keV in germanium on absolute scale. The measur ements were made using two high purity Ge detectors that operated in a coin cidence mode. One detector served as the target and detector of ejected ele ctrons, and another as the detector of Compton-scattered photons. It was fo und that fast (multiple) cascades have little influence on the data of the 105.3 keV crossover transition. An improved determination of the detector e fficiency was made. The calculated values of the cross-section d(2)sigma /d E d Omega using the impulse approximation (IA) with Hatree-Fock (HF) wave f unctions are in excellent agreement with the experimental cross-sections, w hile the IA with hydrogen like (HL) wave functions give fair agreement. A c omparison of the calculated values of the cross-sections obtained with HF a nd HL wave functions for each subshell in germanium gives new values for ef fective charges, which improve agreement between the results of IA with HL and experimental values. (C) 2001 Elsevier Science Ltd. All rights reserved .