Eur. Phys. J. A (2011) 47: 64
https://doi.org/10.1140/epja/i2011-11064-9

Regular Article - Experimental Physics

Improved characteristics of the 22.5 keV (M1 + E2) nuclear transition in ¹⁴⁹Sm

¹ Laboratory of Nuclear Problems, JINR, Dubna, Moscow Region, Russian Federation
² Institute of Applied Physics, National University, Tashkent, Republic of Uzbekistan
³ Nuclear Physics Institute of the ASCR, Řež near Prague, Czech Republic

^* e-mail: inoyatov@nusun.jinr.ru

Received: 2 February 2011
Revised: 4 April 2011
Accepted: 19 April 2011
Published online: 25 May 2011

Abstract

The gamma ray and conversion electron spectra of the 22.5keV M1 + E2 nuclear transition depopulating the first excited level 5/2⁻ in ¹⁴⁹Sm were investigated in detail. A substantially improved value of 22500.2 ± 0.8 eV for the transition energy was determined that opens a possibility to establish an electron energy standard for the keV region based on the conversion electron lines of this transition. The E2 admixture parameter |δ(E2/M1)| = 0.0784 ± 0.0009 and the nuclear structure parameter λ = − 2 ± 10 were derived. The |δ(E2/M1)| and λ parameters were also obtained for all available experimental data and their mutual combination.