The decay of 191Pt(3.0 d) to 191Ir

Abstract

The electron capture decay of 191Pt(3.0d) to excited states in 191Ir has been studied with a lithium-drifted germanium detector and a scintillation spectrometer. Singles and coincidence spectra were obtained. Previously reported transitions of 82.45 keV (M1+E2), 96.5 keV (M1+E2), 129.45 keV (M1+E2), 172.3 keV (M1), 179.0 keV (M1+E2), 187.75 keV, 213.8 keV, 219.8 keV, 221.9 keV, 223.7 keV (E2), 269.1 keV, 351.5 keV (M1), 360.3 keV (M1), 409.9 keV (M1), 457.0 keV (M1), 493.0 keV, 495.1 keV, 539.5 keV (M1), 569.1 keV, 575.6 keV, 584.2 keV, 588.3 keV (M1), 624.6 keV (M1) and 632.6 keV were verified. Hitherto unreported weak transitions of energy 659±2 keV and 762 keV were observed. Evidence has been found for a level at 588.3 keV recently postulated on the basis of an interpretation of resonance fluorescence measurements in 191Ir. The present data are consistent with a level scheme with states at 82.45 keV( 1 2 +), 129.45 keV( 5 2 +), 171.25 keV( 11 2 −), 179.0 keV( 3 2 +), 351.4 keV ( 5 2 +), 539.3 keV( 3 2 +), 569.1 keV( 7 2 +), 588.3 keV( 5 2 +), 624.5 keV( 5 2 +), 762.2 keV and and 838 keV . Ratios of experimental gamma-ray transition probabilities from the 539.3 keV, 351.4 keV and 179.0 keV states are presented. Absolute experimental M1 transition probabilities in the de-excitation of the 624.5 keV, 588.3 keV, 539.3 keV, 129.45 keV and 82.45 keV levels are compared with the Weisskopf and Nilsson estimates.