ABSTRACT
The purpose of making radiation measurements is usually to infer information about the source of the radiation. The absolute efficiency depends critically on the detector’s performance characteristics and on the geometrical positioning of the detector with respect to the radiation source. Preparation of the source material and its encapsulation has an effect on the emission rate of radiation from the source assembly. The exception may be for low-energy photons in heavy encapsulation. However, scattering from walls, floors and other massive objects in the room can make a significant difference in a radiation measurement, especially when dealing with neutron sources. A measurement taken in the presence of a radiation background overestimates the result for any sample under investigation. Correction for window effects is very difficult because such corrections depend on the type of radiation, its energy, its angle of incidence to the window, the window material, and the window thickness.
