Ge70high-spin levels via theZn

Abstract

The nucleusGe has been studied via the +Zn{n, 2ny) Ge reaction at E~= 30 MeV using different in-beam y spectroscopic techniques. Levels up to 5.5 MeV have been identified and spins up to 8+ have been established.NUCLEAR REACTIONS +Zn{n, 2ny) E~= 30 MeV, yy coincidences, angular distributions, level scheme deduced.

Observation of aγband based on a two-quasiparticle configuration inGe70

“…The ground state positive-parity band determined from the present work is shown in Fig.1 as band B1. This band was known previously up to spin, J π = (12 + ) [12,15,24] and is extended to 14 in the present work with inclusion of 1051 keV γ-ray transition on top of 12 + level. An example of γ-γ coincidence spectrum gated on 906 keV is shown in Fig.…”

“…Low-spin states of 70 Ge were previously investigated through the (p, p ′ ), (n, n ′ γ), (p,t) and ( 3 He, d) reactions [10][11][12][13]. These studies reported the level structure of 70 Ge up to 5.1 MeV excitation energy.…”

High spin levels in 70Ga via 68Zn(α, pnγ) 70Ga

“…Indeed the 199/2-2P3/2 proton splitting (1 972 keV in 69Ga [13]) and the small 199/2-2pl/2 neutron splitting (198 keV in ' 1 Ge [14]) enables us to build high spin states up to 9 + . As a support we may note the work of C. C. Lu et al [15] 68Zn(a, 2ny)'°Ge which was used in our study of 7 'Ge [17] and 68Zn(a, pn7)7'Ga with a cross section (estimated by means of the y transitions to the G.S.) which is 10 times smaller than that of the (a, 2n) reaction.…”

“…which is 10 times smaller than that of the (a, 2n) reaction. We shall only describe here the experimental set-up specific to the 7OGa study and ask the reader to refer to the7OGe paper [17] for any further information.…”

“…4) performed with the code DIAM [21] written with the formulas of T. Yamazaki [22]. As explained in [17], we choose the solution with the best X2 , and moreover, when this last criterion is ambiguous, we prescribe that for a given level, the alignment parameter coefficient a2 deduced from the angular distribution analysis of the y-rays feeding this level, should be as near as possible to the a2 deduced from the data of the y-ray emitted by the level. This criterion induces the alignment to decrease as the nucleus is deexcited down the yrast cascade, with a starting value near 1 (i.e.…”