Energy Alinement of Gamma Spectrometers

One of the key requisites to proper operation of a gamma spectrometer is accurate energy alinement. Prominent among the characteristics of such systems which can affect energy alinement are the nonlinear response of scintillation crystals, the effects of the geometry of the source, and electronic performance--such as the variability in response to different counting rates and the shifts which occur in the zero and gain settings. Regular checking of instruments, followed by any corrective adjustments indicated, is requisite to proper operation of a gamma spectrometer. In addition, control charts for documenting and monitoring instrument performance need to be set up. Regular application of such procedures will provide continual assurance that the data obtained from such a system are precise and accurate. Under normal conditions, information thus obtained will afford an accurate foundation on which to base public health evaluations of given radiological contaminations. In the event of elevated levels, the accuracy of such data will be indispensable to the application of sound procedures for corrective public health action. The recommendations in the paper are directed particularly to public health personnel who have not had extensive experience in the detailed use and calibration of gamma spectrometers.