Improved methodology for a collinear dual-energy gamma radiation system

Improved procedures are presented for the measurement of water content and soil bulk density using a collinear 241Am and 137Cs gamma radiation system. More accurate procedures than those previously available are offered to correct the americium count rate for dead time and Compton-scattered cesium radiation. Procedures are also presented for the direct measurement of system dead times, based on single-channel analyzer control of dead time. The concept of a maximum system processing rate is discussed, particularly emphasizing its implications for the theoretically achievable measurement precision using available technology. A calibration procedure is offered to improve this precision, by reducing or eliminating the highest (empty cell) count rate from the calibration procedure. To also improve the theoretical system precision, the optimal range of the ratio of corrected americium to cesium count rates is found. A method is presented for determining the actual precision and accuracy of measurements