Accurate determination of Compton backscattering in germanium at 86.5 keV on an absolute scale

The double-differential cross section {d}^{2}\ensuremath{\sigma}/d\ensuremath{\Omega}\mathrm{dE}for Compton backscattering in germanium was measured at the photon energy of 86.5 keV. The experimental setup with two high-purity germanium detectors operating in the coincidence mode was applied. A multiline radioactive source of {}_{63}^{155}\mathrm{Eu}was used as the source of photons. The Compton spectrum with a very small background was...