Experimental re-evaluation of the gammy-ray energy and emission probability for the 159 keV transition in 238U followed by the alpha-decay of 242Pu

Because of the very low specific activity of 242Pu, the non-destructive assay of this isotope by means of conventional high-resolution gamma-spectrometry (HRGS) is only possible for Pu samples highly enriched in 242Pu. For bulk samples suffering from the gamma self-attenuation and self-fluorescence effects, the weak gammy-line emitted in the 159 keV transition of 238U practically represents the only choice for the quantitative analysis of 242Pu. A recent study revealed a significant disagreement between the 242Pu mass values in a 99.72 % enriched 242PuO2 sample as reported by HRGS and neutron coincidence counting. This fact motivated the present study on the experimental re-evaluation of the gammy-emission probability for the 159 keV transition using a combination of alpha-, gamma- and mass-spectrometry techniques. The obtained new emission probability P2 = (2.20 ¿ 0.08)¿10-6 turned out to be ¿ 35% smaller than the currently adopted value. The study also suggested a new value E2 = 159.018 ¿ 0.016 keV for the energy of the respective gamma-ray. Keywords: U-238, ground state rotational band, gamma-transition, gamma-ray, emission probability, energy, Pu-242, alpha-decay

BERLIZOV Andriy;  VAN BELLE Pieter;  ZULEGER Evelyn;  OTTMAR H.; 

2011-01-14

PERGAMON-ELSEVIER SCIENCE LTD

JRC62307

0969-806X,   

www.elsevier.com/locate/apradiso,    https://publications.jrc.ec.europa.eu/repository/handle/JRC62307,   

10.1016/j.apradiso.2010.11.017,