Characterization of the virtual point detector effect for coaxial HPGe detectors using Monte Carlo simulation

The scaling of detector efficiency with source distance is generally a complex function of the detector shape and measurement geometry. The concept of a virtual point detector has been developed and validated in the past for Ge (Li) and HPGe detectors to deal with this problem. Characterizing the virtual point detector effect has traditionally involved tedious and time-consuming measurements at multiple energies and source distances. The situation is therefore well suited to a Monte Carlo approach. In this paper, the results of using Monte Carlo simulation to characterize the virtual point detector effect for large-volume coaxial HPGe detectors are presented.