Nuclear structure effects in the 343 keV M1 transition in 175Lu

Abstract

The conversion coefficients of the 343 keV transition in 175Lu were measured via the internal-external conversion method using an automatic 50 cm double-focussing spectrometer and various uranium converters. The experimental values are α K = 0.086±0.004, α L1 = 0.0121±0.0005, α L2 = 0.00115±0.00007 and α L3 = 0.00028±0.00002. From these conversion coefficients and the C S coefficients of Nielsen, the penetration parameter of the 343 keV transition in 175Lu is calculated to be λ 343 = +4.5±1.5. The corresponding mixing ratio is found to be δ 343 2 = 0.069±0.015. These values are consistent with the Rose K, L 1, L 2and L 3 or Sliv and Band K, L 1 and L 3 theoretical conversion coefficients. For complete consistency with all the theoretical conversion coefficients, the Sliv and Band β 1(L 2) would have to be lowered by about 15%. From λ 343, the absolute value of λ for the 482 keV transition in 181Ta is found to be | λ 482|≈ 270±100. Using the sign of λ 343 in Wahlborn's theoretical analysis for the circular polarization P resulting from parity impurities in the 343 keV level of 175Lu, the value of P is expected to be negative and of the order 10 −4.