A new high-spin isomer in 39 97 Y58

Abstract

An isomeric state at 3,523 keV excitation energy in 97y with a half-life of 144(10) ms has been discovered with the fission-product separator JOSEF. This isomer is depopulated through a ? transition of 162 keV. An E3 multipolarity for this transition is consistent with the measured conversion coefficients of 0~K = 0.98 (20) and er = 1.00 (19). Subsequent electromagnetic transitions populate several new 97y levels which have high spins. For the isomer the three-quasiparticle configuration [gg9/2 @v(hl 1/2, g7/2)]27/2-is proposed. The E3 transition with a strength about 2 single-particle units is supposed to be of the type h+~2-*ds/~ . These findings provide evidence for the rapid shape transition 97 at A-~ 100 since they indicate shell-model character of 39Y58 even at high excitation energies while the immediate neighbour 998Y59 contains a rotational band based on a level at 495 keV.

IBMF and IBFFM Approach to Nuclei in the A≃100 Region

“…The nucleus 97y. with one proton hole and two neutron particles beyond 96Zr • has been recently investigated experimentally [17]. A particularly interesting feature of this nucleus is a family of unique-parity levels, associated with g9/2 proton configuration.…”

Nuclear structure of97Y in the interacting boson-fermion model

“…We note that the yrast line band pattern changes its character at the angular nomentum 19/2: the levels 9/2, 13/2, 11/2, 17/2, 15/2 exhibit a decoupled-type band pattern, which is followed by the 19/2, 21/2 levels with the normal ordering. Such a change of bandtype is associated with the anharmonicities in the SU (5) It should be mentioned that the presently available experimental information does not exclude [4] an inversion of the levels which have been observed in the radiation from the isomer at 3523 keV in 97y. Thus the set of states labeled as Exp b in Fig.…”

“…Recently, the nucleus 97y with one proton hole and two neutron particles beyond 96Zr has been investigated [3,4]. A particularly interesting feature of this nucleus is a family of levels which are probably associated [1][2][3][4] with the g9/2 proton configuration.…”

“…A particularly interesting feature of this nucleus is a family of levels which are probably associated [1][2][3][4] with the g9/2 proton configuration. These levels have been disclosed through the discovery of a high-spin isomer at 3523 keV in 97y which is populated in fission and which is interpreted as a three-quasiparticle configuration with a g9/2 quasiproton involved.…”

First identification of high-spin states in the odd-odd neutron-rich nucleus152Pr

“…To find the transitions belonging to 152 Pr, we doublegated on transitions in its fission partners, yttrium isotopes. Figure 1 shows a spectrum gated on the 989.9-and 911.4-keV transitions in 97 Y [13] which is the strongest fission partner of 152 Pr. In Fig.…”