Improved energy of the 21.5 keV M1 + E2 nuclear transition in 151Eu

Abstract

Using internal conversion electron spectroscopy, improved energy 21 541.5±0.5 eV was determined for the 21.5keV M1 + E2 nuclear transition in 151Eu populated in the electron capture decay of 151Gd . This value was found to agree well with the present adopted value but is much more accurate. A value of 0.0305±0.0011 derived for the E2 admixture parameter $ \vert\delta(E2/M1)\vert$ from the measured conversion electron line intensities corresponds to the present adopted value. A possible effect of nuclear structure on the multipolarity of the 21.5 keV transition was also investigated.