APPARATUS AND METHOD FOR CALIBRATION OF NUCLEAR GAUGES

摘要

The present invention is directed to a method and apparatus for calibrating nuclear gauges and confirming gauge calibrations that provide the accuracy o f multiple block calibration methods without requiring multiple standardized calibration blocks of known density. The apparatus includes a support for receiving a nuclear gauge of the type having a radiation source and a radiation detector and a variable radiation filter operatively associated wi th the support for providing variable attenuation of radiation emitted from the radiation source. The variable radiation filter includes a block having an eccentrically located cavity and positioned for rotation about the central axis of the cavity. The filter may further include a fixed mass for further attenuating radiation discharge by the radiation source such that the energy spectrum produced by the filter substantially matches the energy spectrum of a solid block of material, such as a standardized calibration block.