Mössbauer effect in Tm169 and total internal conversion of the 8.42-keV transition

The absolute yield of the Mössbauer absorption of the 8.42-keV transition in Tm169 was determined for a thulium oxide and a thulium metal absorber. The 8.42-keV gamma ray was resolved from the L x rays of erbium by means of a flat lithium fluoride crystal diffraction spectrometer. From the observed Mössbauer absorption effect the total conversion coefficient αtot=325±35 and the magnetic transition rate of B(M1, 3/2→1/2)=5.1×10^-2 (eh/2Mc)^2 was derived.