Corrections of the emission probabilities of the intense gamma rays of ^238U and ^235U
Abstract
In the past several years, non-destructive assay (NDA) techniques have been developed for uranium isotopic measurements. Most of these NDA methods involve the measurements of X-rays and gamma-rays. This requires the precise knowledge of the gamma-ray emission probabilities, particularly those of ^235U and ^238U. While the branching ratios of ^235U are well known, the branching ratios of ^238U and its daughters differ widely from one study to another. Our study indicates that one of the causes of the large discrepancies of the studies maybe due to the true coincidence summing of many gamma rays from the decay of ^238U daughters. The intensities of some intense gamma rays of ^238U compared to the others were reduced by as much as about 16% when the 21 mm thick U_3O8 samples were moved from 15 cm to contact with the detector. The purpose of this study is to precisely determine the emission probabilities and the intensity-attenuation due to summing of the most intense gamma-rays of ^238U decay chain (and also of ^235U). This would allow us to analyze the isotopic concentration of uranium more accurately. (LA-UR-98-2921).
- Publication:
-
APS Division of Nuclear Physics Meeting Abstracts
- Pub Date:
- October 1998
- Bibcode:
- 1998APS..DNP..B308V