Determination of a source in a box with two detectors. The general case

The study on using two detectors in order to measure accurately the activity of an unknown radioactive point source in a large bulky sample, named “a box”, was expanded to the general case, including the geometrical and absorption effects together. Two NaI(Tl) detectors were positioned at the opposite sides of the sample, and mathematical correlations of the count rates were used to develop an algorithm, which gave quantities independent on the source location. The mathematical algorithm was validated by experimental results. This method reduces to a great extent the uncertainty of the activity determination.