Cross sections and isomer ratios for some neutron capture reactions

Abstract

Neutron capture cross sections leading to the isomeric states in seven nuclei have been measured, for the first time, using the activation technique and absolute gamma counting method, employing an antimony-beryllium neutron source and a calibrated well-type NaI(Tl) crystal. In two reactions, 116Cd(n, gamma )117m,gCd and 151Eu(n, gamma )152m1,m2Eu where cross sections have been measured for a pair of states in each case, the 'isomeric cross section ratio' has been employed to extract the spin cutoff factor following Huizenga and Vandenbosch formalism. A comparison is made with theoretical predictions based on various models of level density to throw light on the nuclear moments of inertia.