Correction for Full Energy Peak Efficiency to Disc Source of Ge (Li) Detector

Abstract

The full energy peak efficiencies (FEPE) to Ge (Li) detectors with three different radius r_D have been measured by using point sources of ²⁴Na, ⁵⁴Mn, ⁵⁷Co, ⁶⁰Co, ¹³³Ba and ¹³⁷Cs, as functions of source-detector distance d and of distance L from the center axis of the detector.
Using the reduced distance l which is L/r_d, all measured FEPE distributions for d and gamma-ray energy E are found to be scaled approximately to an universal curve. This curve is simply fitted to a quadratic equation of l for each d and E. The coefficient of a squared term is also found to have a simple relation against d and E.
The correction factor K_c (r, d, E) of FEPE to disc sources with reduced radius r, using the same notation as 1, is easily calculated by these equations. The calculated K_c (r, d, E) values are in good agreement with measured ones by using a disc source of ²⁴Na.