Evidence of an after-effect in the ( n , γ ) reaction on polycrystalline hafnium (IV) acetyl-acetonate complex

Abstract

Perturbed differential angular correlation measurements were performed on the 133-482 keV γ -cascade of 181 Ta in synthetic and neutron irradiated polycrystalline Hf ( AA ) 4 sources. Evidence is presented showing occurrence of different crystalline sites in the two cases. The experimental data have been treated by means of a X 2 test. Electric field gradients and asymmetry parameters are evaluated and discussed in terms of possible crystalline structures.