Correction of the gamma emission spectrum of a thulium-170 source for the response function of the detector

The determination of the gamma emission spectrum of a radioactive source is a relatively complex problem. A direct measurement using a spectrometer produces a distribution which is the product of the primary spectrum by the reponse function of the detector. The response function can be broken down into the efficiency curve of the detector, losses due to Compton diffusion, and gamma summing effects. In this study a Ge(Li) detector was used to count a Th-170 source. The source was either uncovered, screened by aluminum, or in a container with a lead collimator