27.7-keV Level inI129and Some Remarks about Its Use in Mössbauer Experiments

Abstract

The properties of the first excited state of I m have been studied with a mass-separated Te 129m source. The energy of this state, as determined from the conversion-electron spectrum, is JS 7 =27.72d=0.06 keV. This differs considerably from the often quoted value of 26.8 keV, but it agrees very well with the value recently published by Bemis and Fransson. An accurate half-life value ri/ 2 =16.8±0.2 nsec was determined from delayed /3e~ coincidences. A total conversion coefficient a=5.3±0.3 was obtained from the relative intensities of the 27.7-keV gamma rays and the 27.4-keV x rays that accompany the isomeric transition in Te m . The contributions of these rays were separated by comparing Mossbauer spectra obtained with the 70-min and 33-day activities of Te 129 . Some remarks are made about the relative merits of these activities for use in Mossbauer sources.

Rare-Earth Tri-iodides—Mössbauer Effect Using 129I

“…3 The apparatus for Mossbauer spectroscopy is a All measurements were done with source and absorbers at liquid nitrogen temperature. Purification and source synthesis were done along the lines described by Sanders and de Waard.…”

“…3 With the static field in the direction (t'J, <{» this probability is 3 g12= [glgl sin 2 t'J+ gIl2gz2(sin 2 <{>+ cos 2 t'J cos 2 <{» +g}g,,? 3 With the static field in the direction (t'J, <{» this probability is 3 g12= [glgl sin 2 t'J+ gIl2gz2(sin 2 <{>+ cos 2 t'J cos 2 <{» +g}g,,?…”