Experimental investigation of the 9.2 and 24.3 keV nuclear transitions in Th

A. Kovalík; A. Kh. Inoyatov; L. L. Perevoshchikov; M. Ryšavý; D. V. Filosofov; J. A. Dadakhanov

doi:10.1140/epja/s10050-021-00577-7

2024 Impact factor 2.8

Hadrons and Nuclei

Eur. Phys. J. A (2021) 57: 285
https://doi.org/10.1140/epja/s10050-021-00577-7

Regular Article - Experimental Physics

Experimental investigation of the 9.2 and 24.3 keV nuclear transitions in $^{227}$ $^{227}$ Th

A. Kovalík¹^,2, A. Kh. Inoyatov¹^,3, L. L. Perevoshchikov¹, M. Ryšavý²^d, D. V. Filosofov¹ and J. A. Dadakhanov¹

¹ Dzhelepov Laboratory of Nuclear Problems, JINR, 141980, Dubna, Moscow Region, Russian Federation
² Nuclear Physics Institute of the ASCR, 25068, Řež Near Prague, Czech Republic
³ Nuclear Physics Institute of the ASUzR, 100214, Ulugbek Near Tashkent, Republic of Uzbekistan

^d rysavy@ujf.cas.cz

Received: 25 May 2021
Accepted: 19 August 2021
Published online: 12 October 2021

Abstract

The 9.2 and 24.3 keV nuclear transitions in $^{227}$ $^{\mathrm {227}}$ Th were studied in the $β^{-}$ $\upbeta ^{-}$ decay of $^{227}$ $^{\mathrm {227}}$ Ac employing the internal conversion electron spectroscopy. Values of $(9244.6 \pm 0.8)$ $(9244.6 \pm 0.8)$ and $(24343.1 \pm 1.1)$ $(24343.1 \pm 1.1)$ eV were determined for their energies. The 24.3 keV transition was found to be of the mixed (M1 $+$ $$+$$ E2) multipolarity with the spectroscopic admixture parameter $δ^{2}$ $\delta ^{\mathrm {2}}$ $(E 2 / M 1)$ $$(E2/M1)$$ = $(0.0116 \pm 0.0004)$ $(0.0116 \pm 0.0004)$ . Energies of $(24342.9 \pm 1.2)$ $(24342.9 \pm 1.2)$ , $(28613.3 \pm 1.7)$ $(28613.3 \pm 1.7)$ , and $(37860.2 \pm 2.0)$ $(37860.2 \pm 2.0)$ eV were obtained respectively for the 24.3, 28.6, and 37.8 keV transitions in $^{227}$ $^{\mathrm {227}}$ Th by means of the gamma-ray spectroscopy. Natural atomic-level widths of $(14.1 \pm 0.5)$ $(14.1 \pm 0.5)$ , $(11.4 \pm 0.5)$ $(11.4 \pm 0.5)$ , $(6.9 \pm 0.4)$ $(6.9 \pm 0.4)$ , $(11.4 \pm 1.4)$ $(11.4 \pm 1.4)$ , $(8.6 \pm 1.2)$ $(8.6\pm 1.2)$ , and $(6.0 \pm 0.7)$ $(6.0 \pm 0.7)$ eV for the M $_{1}$ $_{\mathrm {1}}$ -, M $_{2}$ $_{\mathrm {2}}$ -, M $_{3}$ $_{\mathrm {3}}$ -, N $_{1}$ $_{\mathrm {1}}$ -, N $_{2}$ $_{\mathrm {2}}$ -, and N $_{3}$ $_{\mathrm {3}}$ -subshells of thorium, respectively, were derived from conversion electron lines. The cross checking of the energy values of the 9.2, 15.1, and 24.3 keV nuclear transitions obtained by the ICES method is also given.