Abstract: A position sensitive radiation spectrometer for identifying, quantifying, and locating a radioactive source in a target. The position sensitive radiation spectrometer includes an array of gamma-ray detectors arranged along one or more dimensions of a container to be assayed. A known source placed at various calibration positions is used to establish counting efficiencies at various energy levels. From the counting efficiency and the actual count rate, the activity level of an unknown source relative to the calibration positions is calculated. The relative activity levels correlate to the position of unknown source and provide useful information about the actual distribution of radioactive material.

Abstract: A differential correction apparatus for use with a spectroscopy device. The spectroscopy device simultaneously produces two histograms corresponding to the spectrum acquired. The first histogram contains the counts recorded by a differential correction method (DCM), giving the best estimate of the counts per channel in the absence of dead time. The second histogram is the error spectrum, giving the variance of the counts in each channel of the first spectrum. The two spectra have the same size, true acquisition time, and energy calibration with the only difference being the number of counts in each channel. By obtaining both histograms, it is possible to both obtain an accurate spectrum when the energy peaks have varying decay times and retain the necessary information about the spectrum to allow the statistical error to be calculated.