Thermal-neutron capture gamma-rays from some rare-earth elements

Abstract Capture γ-ray spectra have been measured using a scintillation spectrometer. Strong lines were observed below 300 keV with Eu, Gd, Dy; Ho, Er, Tm, Hf and Ta. In the spectra of 168 Er and 178 Hf, lines of intensity 0·5–0·8 quanta per capture have been attributed to transitions of the type 4 + a 2 + and 2 + a0 + between rotational levels.