Attenuator Calibration Factors Using High and Low Activity Sources

Abstract

Compliance with Nuclear Regulatory Commission regulations pertaining to the range of activities over which linearity of dose calibrators must be tested requires that the procedure be done with two separate sources (one with high activity; the other with low activity) when the attenuator method of checking dose calibrator linearity is used. This may lead to an incorrect judgment of instrument nonlinearity if the same calibration factors are used for both sources. Disparity in calibration factors as high as 6%-9% has been observed. Possible methods for modifying these calibration factors are identified and include: (1) utilizing different factors for high and low sources; (2) modifying the high activity factors by use of established ratios for use with low activity sources; and (3) averaging a series of factors from high activity sources with those from low activity sources.