Determination of thermal neutron capture gamma yields.

Abstract

A method of analysing Ge(Li) thermal neutron capture gamma spectra to obtain total gamma yields has been developed. Tie method determines both the yields from the well resolved gamma peaks in a spectrum as well as the gamma yields from the unresolved gamma lines which appear in the continuum portion of a spectrum. Accounting for the unresolved continuum enables a large fraction of total emitted energy to be observed, and values of 100% +/- 15% are obtained for the cases studied. The techniques used involve the determination of a peak response function suitable for the Ge(Li) pair spectrometer spectra being studied. The response function is used to strip off the effects of the peaks upon the background and unresolved data continuum. The continuum, which is due only to the unresolved lines, is broken into energy bins of 210 keV width and the gamma yield per bin is calculated. Results of the analysis and normalized yields are given for the rare earth samples of: Nd, Sm, Eu, Gd, and Er. The capture data were obtained by using the MITR 4th irradiation facility operated with a Ge(Li) pair spectrometer.