Geometry effects in well-type Ge-detectors due to the introduction of high-Z linings

In well-type detectors and other highly efficient geometries, the combined effects of sample self-absorption involving low-energy gamma-rays and coincidence summing of a low- and a high-energy photon often influence the entire gamma-spectrum of a radionuclide. For well-type detectors, these effects are well understood and it should be possible to correct for these effects analytically. Another possibility to deal with these effects is to prevent the low-energy gamma-rays from reaching the detector by lining the well with a high-Z material, as was suggested in the past. We present a series of measurements which indicates that the problems resulting from sample self-absorption and coincidence summing should be treated analytically rather than by attempts to eliminate the effects by means of a lining.