Nuclear structure of the first2+state in radioactiveGe68based ongfactor and lifetime measur

Abstract

The g factor of the 2 + 1 state of radioactive 68 Ge (T 1/2 = 270 d) has been measured for the first time. The technique used is based on α transfer from a 12 C target to energetic 64 Zn projectiles that incorporates the favorable conditions of inverse kinematics as in projectile Coulomb excitation. It also includes features of the transient field technique applied to nuclear spin precessions. Because the reaction cross section is large the method is a significant alternative to Coulomb excitation of low-intensity radioactive ion beams. In addition, we have remeasured the lifetimes of several excited states using the Doppler-shift-attenuation method. In these measurements, the inherent focusing nature of the reaction in the forward direction was optimally exploited for the resulting fast-moving nuclei. The g factor value obtained, g(2 + 1 ) = +0.55 (14), is in good agreement with the collective value, g = Z/A = 0.47, and is also consistent with the precise data of the stable even-A Ge isotopes. The newly determined lifetimes partially agree with those quoted in the literature and are of comparable accuracy. The deduced B(E2) values and the new measured g factor are well reproduced by some fp shell model calculations in which excitations from the f 7/2 orbital play an important role.

Collectivity in66Ge and68Ge via lifetime measurements

“…In addition, there has been a precise measurement by Ref. [17] of τ = 3.1(2) ps using the Doppler Shift Attenuation Method, which the present result is in very good agreement with.…”

Experimentalgfactors andB(E2)values of21+,Leske1, Speidel2, Schielke3 et al. 2005Phys. Rev. CSelf Cite271250View full textAdd to dashboardCite

“…With this nuclear reaction, a novel technique for determining g factors, lifetimes, and feeding patterns in radioactive nuclei was established under the same favorable conditions as in projectile Coulomb excitation experiments employing inverse kinematics. This method has so far been successfully applied to the spectroscopy of radioactive 44 Ti (T 1/2 = 60 yr) [2] and 68 Ge (T 1/2 = 270 d) [3] using ordinary stable beams of 40 Ca and 64 Zn, respectively. In both cases, the 2 + 1 states were preferentially populated, which allowed the deduction of the g factors from the measured precessions without requiring any significant correction for contributions from high-lying states.…”

“…The lin /g values were calculated using Eqs. (1)-(3). Only in run I was the beam energy 175 MeV, whereas in all other runs the energy was 180 MeV.…”

Population of the2ms+mixed-symmetry state ofBa140with theα-transfe

“…Therefore, in our experiment, a clean identification of the α-transfer reaction channel is mandatory. α transfer has been successfully used for the population of excited states in radioactive nuclei close to the valley of stability in several experiments, e.g., [13,14].…”