In-beam study of excited states in80Br

Abstract

Excited states of the doubly-odd nucleus 8~ have been studied via the reactions 8~ n), S~ 2n) and 78Se(~,pn) using in-beam y-ray spectroscopy. A positiveparity level sequence built on a P= 5 + state at 331.04 keV has been found up to spin (10). For this 5 + level de-exciting to the known 5-isomeric state and for the 6 + level at 357.22 keV half-lives of 0.7 and 0.4 ns, respectively, have been determined. Negativeparity states have been observed up to spin (6). For the positive-parity level sequence the configuration (ng9/z, vg9/2) and collective excitations are proposed. Some of the negative-parity states are tentatively interpreted as arising from the configurations (~P3/2, vg9/2) and (np3/2 , (vg9/2)37/2). Nuclear Reactions." 78Se(cc, pn), E=23, 27MeV; measured ET, a(E,E~,O),77-coin., 0r 8~ 2n), E=13.5 MeV; measured E~, a(E~, 0), yT-coin.; 8~ n), E=6.7 MeV; measured E~, a(Ey); 8~ deduced levels, J, n, T1/2. Enriched targets. Ge (Li) detectors.

Yrast states in81Br and82Br

“…8). This level structure resembles very much the positive-parity high-spin sequence found in 8~ [17]. The large alignment of i~ 6 h with the 500 keV higher position of the 9/2 + excitation.…”

“…This statement is partly supported by the variation of the ratio of reduced transition probabilities of the M1(8 + ~7 +) to the E2(8 + --*6 +) transitions from 1.2, 3.0, 2.6 to >4.8 x (10 .6 fm -2) for v4'76'78'8~ respectively [17]. This statement is partly supported by the variation of the ratio of reduced transition probabilities of the M1(8 + ~7 +) to the E2(8 + --*6 +) transitions from 1.2, 3.0, 2.6 to >4.8 x (10 .6 fm -2) for v4'76'78'8~ respectively [17].…”

“…J._. An upper limit of 0.3 ns was also obtained[17] for the 119.1 keV transition assigned to SlBr. '~';''''''I "'''I''' 'I .... h:,-,~k .... t...= ~_ ,, .,.+._ ,., +~ ........ + ............ : ........ L. ..... J ...... !…”

“…Upper lifetime limits of some low-energy transitions in the two Br isotopes have been determined from the pulsed beam 7-timing measurements in connection with the bombardment of 8~ or 78Se with 27 MeV c~-particles as described in [3,17]. In these experiments a 2 cm 3 high-resolution Ge detector has been used to record the 7-rays.…”

“…The data are taken from[17,[19][20][21] and this work. The data are taken from[17,[19][20][21] and this work.…”