Sensitivity of the combined radiation method of measuring the local thickness of a pipe wall

The sensitivity of radiation gauges of the local thickness of a pipe wall to changes in the inspected and uninspected sections of the wall is analyzed. Relative sensitivity of the detectors of direct and scattered radiation is shown as a function of the pipe wall thickness. The combined method of measuring the wall thickness of pipes is used in which the pipes are diametrically irradiated by a collimated beam. Algorithms and experimental methods using cesium 137 as a radiation source are given for assessing sensitivity and evaluating measurement errors.