New ¹⁶⁹Tm Mössbauer Source

Abstract

ALTHOUGH the lanthanides are rich in Mössbauer isotopes, only a few Mössbauer studies of lanthanide compounds have been reported. This is especially true for thulium compounds, for which there have been several difficulties. First, the relatively short half-life (t_1/2 = 3.9 ns) of the Mössbauer (+_3/2) excited state gives a minimum observable width of 8.340 mm/s; second, the sources used contain ¹⁶⁹Er as the fluoride or oxide and have to be heated to 550 K and 800 K, respectively, to give an unsplit line.