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Improved methodology for a collinear dual‐energy gamma radiation system
Author(s) -
Stillwater Roger,
Klute Arnold
Publication year - 1988
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr024i008p01411
Subject(s) - calibration , dead time , radiation , spectrum analyzer , accuracy and precision , detector , nuclear engineering , range (aeronautics) , americium , optics , physics , computer science , computational physics , materials science , nuclear physics , actinide , engineering , quantum mechanics , composite material
Improved procedures are presented for the measurement of water content and soil bulk density using a collinear 241 Am and 137 Cs 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.