Properties of Nuclear Levels in a Number of Odd-ANuclei (151≤A≤191)

Abstract

In order to obtain more evidence on the systematic behavior of nuclear energy levels in the deformed region, a number of neutron-deficient odd-mass activities were studied with internal conversion electron spectrographs. Some scintillation counter measurements were made. Level schemes are postulated for decays leading to the following odd-neutron nuclei: Pm 151 -* Sm 151 , Tb 151 -» Gd 151 , Tb 153 -> Gd 153 , Tb 155 -> Gd 155 , . As a corollary, data are presented for the odd-proton nuclei populated in the decays of Pt 189 -» Ir 189 and Pt 191 -* Ir 191 . The proposed states are described using the Mottelson and Nilsson predictions. Some conclusions may be drawn concerning such properties of these orbitals as moments of inertia, Ml/El mixing ratios, and positions of the intrinsic excitations. Ratios of gamma-ray transition probabilities from the various states are given. Previously published studies of odd-^4 nuclei in the region of odd-TV numbers 99-107 are incorporated in the energy-level systematics.

Levels in189Os populated in the decay of189Re

“…Malmskog et aL [6] concluded that the 185.85 keV y-ray was M I from the internal conversion coefficient. Crasemann et al [I] and Harmatz et al [4] also found this ?-ray to be M1 by the k/L~ subshell ratio. The c~ K computed by Hager and Seltzer [12] with a spline interpolation is 0.825.…”

“…[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. The most recent study of ~89Os levels was made by Malmskog et aL [6] where isotopically separated sources of ~89Ir were produced at CERN and the radioactive decay v-rays and conversion electrons were measured and the lifetimes of excited 189Os levels were determined.…”

Magnetic moment of the 5/2?1/2[541] ground state of 14h 185Ir

“…In analogy to the heavier odd Ir isotopes 'SVIr, 189Ir, 191Ir and 193Ir, for which UK [NnzA ] = 3/2 + 3/2 [402J Nilsson ground-state configurations are well established [6], I~K=3/2+3/2 had first been proposed, this assignment being consistent with the /~-decay properties [1]. However, Rubinsztein and Gustafsson [3] measured I=5/2 by the atomic beam magnetic resonance method, and proposed a UK=5/2-1/2 configuration.…”

“…The ground-state configuration of 185Ir has been the subject of much speculation and investigation [1][2][3][4][5]. In analogy to the heavier odd Ir isotopes 'SVIr, 189Ir, 191Ir and 193Ir, for which UK [NnzA ] = 3/2 + 3/2 [402J Nilsson ground-state configurations are well established [6], I~K=3/2+3/2 had first been proposed, this assignment being consistent with the /~-decay properties [1].…”

The Spallation of Iridium With Protons of Energies 9–87 Mev

“…The relative intensities of the 550 and 720 kev y-rays were determined t o be 100 and 56 respectively. From more recent data (22), it would appear that the 550 kev peak observed is in reality a mixture of 545 kev and 608 kev y-rays.…”