0000000001130761
AUTHOR
T. Tuurnala
The Isomeric 9/2+and the Lowest 7/2-State in the Weakly Deformed N = 89 Nuclei
The decays of the isomeric 9/2+ states which have been produced by (d, pγ) and (3He, xnγ) reactions, have been investigated in three N = 89 nuclei. The half-lives have been determined to be 5.1 ± 0.3 ns in 149Nd and 3.5 ± 0.4 μs in 153Gd. In 155Dy a 5.5 ns half-life was found, but we were unable to assign it to the 9/2+ state. The calculated E1 transition probability from the 9/2+ state has been used as a probe in suggesting the following main components for the lowest-lying 7/2- state: 7/2 5/2-[523] in 149Nd, 7/2 3/2-[521] in 153Gd and 7/2 3/2-[521] in 155Dy. The corresponding 7/2- state in 151Sm is proposed to be 7/2{1}3/2-[532] + 5/2-[523]{1}. All calculations have been performed using a…
Low-lying levels in the nuclei151Nd and155Sm
Decay properties of excited states in the151Nd and155Sm nuclei produced by 10 MeV douterons have been investigated with in-beam gamma-gamma-coincidence equipment during bombardment of the150Nd and154Sm targets. The results largely confirm the data obtained earlier for these nuclei. The (d, p γ) reaction channel favors population of odd-parity low-spin levels, whose energies follow the rule of regular band structure for well-deformed nuclei. The level schemes are interpreted with calculations using an axial particle-rotor model with a Woods-Saxon potential.
Level structure of170Er observed in the decay of the 2.76 min170Ho
TheΒ−-decay of the longer-lived170Ho isomer produced through the170Er(n, p)170Ho reaction has been investigated by using a versastile detector and coincidence equipment. The half-life andΒ−-decay energy were determined to beT1/2=2.76±0.05 min andQβ =3.85±0.15 MeV, respectively. In addition to the ground state band and some higher energy levels, the proposed level scheme of170Er contains 11 states between 1.0 and 1.6 MeV (6 new ones), which are connected mutually by previously unknown low-energy transitions. Spin and/or parity assignments based mainly on coincidence data and multipolarity determinations are suggested for most of these states. By using systematic considerations and the nuclea…
States of167Ho from the decay of neutron rich nuclide167Dy
Theβ −-decay of 66 167 Dy produced through the fast neutron reaction170Er(n, α)167Dy has been investigated by using several kinds of detectors and a high-capacity two-parameter recording system. The half-life andβ −-decay energy of167Dy were determined to beT 1/2 = 6.20 ± 0.08min andQ β-=2.35±0.06, respectively. The observed level scheme of 67 167 Ho (completely unknown previously) contains 12 states, among them a 6.0±0.1 μsM2 isomer at 259.3 keV. On the basis of theoretical and systematic considerations combined with multipole determinations, the following Nilsson model assignments are proposed for the lowest states of167Ho: 0 keV (7−/2 [523]), 259.3 keV (3+/2[411]), 319.8 keV (5/2 3+/2[41…