Properties of RadioactiveRe189

Abstract

The new isotope Re 189 has been produced by fast-neutron irradiation of osmium and by the (a,p) reaction on tungsten. The rhenium was separated chemically from the target material. Beta-ray, gamma-ray, and internal conversion spectra have been measured. The mass assignment is confirmed by the observation of eleven electromagnetic transitions in the Os 189 daughter, including the 30.8-keV isomeric transition (6h), all of which were known from the decay of Ir 189 . Rhenium-189 has a half-life of 23.4±1.0 h and emits betaray groups with end-point energies 1000, 780, and 725 keV, and probably others. Results of coincidence measurements lead to some new information about the level scheme of Os 189 . The effects of the expected rotation-particle coupling between low-lying K-l/2 and K=3/2 bands in Os 189 are discussed.

Levels in189Os populated in the decay of189Re

“…The multipolarities for many of the transitions accompanying the decay of ~89Re are deduced by combining the present y-ray intensities with the previous measurement of internal conversion electron intensities by Crasemann et al [1]. The relative intensities for the conversion electrons are reproduced in column 3 of Table 1.…”

“…The y-ray relative intensities are normalized to a value of 235 for the 185.86 keV transition. For 7-rays with no reported energy error, the transition energies are taken from Crasemann et al [1]. The relative photon intensities for the 69.59 and 95.23 keV y-rays were computed from the multipolarities proposed in Ref.…”

“…Crasemann et aL [1] have reported the intensities of the conversion electrons emitted in the decay of this isotope. By combining the 7-ray intensities determined in this study with the conversion electron measurements of Ref.…”

“…In addition to the conversion electron studies of Ref. [1], Blichert-Toft [3] reported the ?-rays emitted in the decay of 189Re as observed with a NaI(T1) spectrometer. Several research groups [4,5] have studied the decay of 13.3-d ~S9Ir to excited levels in ~89Os.…”

“…By combining the 7-ray intensities determined in this study with the conversion electron measurements of Ref. [1], the multipolarities of many of the intense transitions in 189Os are deduced. ?-7 coincidence results confirm the low lying level structure and establishes the presence of two new levels in 189Os.…”