Detection of Mössbauer γ-rays from ⁷³Ge and ¹⁸¹Ta

Lithium-drifted silicon and intrinsic germanium detectors are compared as detectors for the recoilless γ-rays from ⁷³Ge at 13.3 keV and from ¹⁸¹Ta at 6.2 keV. In both cases it is found that the ratio of recoilless gamma counts to noise counts is substantially better with the intrinsic germanium detector. As a result of this improved background rejection, large Mössbauer absorption effects are seen with both isotopes. It is believed that the possibilities discussed here for reducing detector background will be of value in many experiments involving low energy X- or γ-ray fluorescence.