Investigation of the γ-rays accompanying thermal-neutron capture by certain rare-earth nuclei

Abstract

Using a scintillation spectrometer measurements have been made of the spectra of γ-rays accompanying thermal-neutron capture in a number of nuclei.

A number of intense lines have been found below 300 kev in the γ-ray spectra for thermal-neutron capture in europium, gadolinium, dysprosium, holmium, erbium, thulium, hafnium and tantalum. Lines corresponding to 4⁺→2⁺ and 2⁺→0⁺ transitions between rotational levels'of Er¹⁶⁸ and Hf¹⁷⁸ were found in the erbium and hafnium spectra. The intensity of these transitions corresponds to 0.5–0.8 photons per capture event.