Decay of 175Hf and 181Hf

Abstract

Nuclear-physical properties of ¹⁷⁵Hf and ¹⁸¹Hf produced by neutron irradiation of natural hafnium in the SM-3 nuclear reactor were studied. The X-ray and γ-ray spectra were measured with high-energy-resolution HPGe and Ge(Li) detectors. The half-lives T1/2 (days) were determined: ¹⁷⁵Hf 71.9±1.3 and ¹⁸¹Hf 42.12±0.25. The relative intensities (rel. units) of the γ-ray lines (keV) of ¹⁸¹Hf are as follows: 133.03, 54.0±1.6; (136.28 + 136.86), 8.9±0.3; 345.919, 20.4±0.6; and 482.193, 100. The ratios of the intensities in the X-ray spectrum were measured: $^{{175}} {Lu}K_{{\beta }_{1,3} } /^{175} {Lu}K_{{\beta }_{2} } = 3.96(12)$, $^{181} {Ta}K_{{\beta }_{{1,3}} } /^{181} {Ta}K_{{\beta }_{2} } = 3.72(11)$, $^{{175}} {Lu}K_{{\alpha }_1 } /^{175} {Lu}K_{{\alpha }_{2} } = 1.74(5)$, and $^{181} {Ta}K_{{\alpha }_{1} } /^{181} {Ta}K_{{\alpha }_{2} } = 1.70(5)$.