The g-factors of isomeric states in127, 128Xe

Abstract

Excited states in ~27,128Xe were populated in the reaction 9Be+ t22Sn at E~ah=38 MeV. The de-excitation of the isomeric states 7/2 + in 127Xe and 8 in 128Xe was studied using angular distribution and TDPAD methods on molten 1228n targets. The results are T~/2(7/2+)=37+ 1 ns, g(7/2+)= +0.241 _+0.009The experimental g-factors suggest the main configurations vg7/2 and vh 11/297,2 for the isomeric states. Detailed analysis of the combined information from g-factors and transition rates set stringent limits on the admixtures of the wave functions. The quasirotational bands built on the two-quasiparticle 6 and 10 + states are extended to higher spins, (14--) and (16+), respectively, and their structures are analyzed within the framework of the Interacting Boson Model.

Shape-driving effects in the triaxial nucleus,Xe128

“…The measurement of the DCO ratio for the 1196 keV transition depopulating the state at 2228 keV as R DCO = 0.55(4) is in agreement with the J π = 5 − assignment proposed in previous work [4,19]. Figure 4 The intrinsic state at 2786 keV was previously assigned as J π = K π = 8 − following a measurement of the g factor by Lönnroth et al [19].…”

“…In cases where transitions are too weak to be observed in this matrix or are considered to be contaminated, their intensity has been obtained from intensity balances in coincidence spectra. Column 5 of table I includes the measured R DCO values, which for previously known [3,4,19] J = 2 (590, 704, 775, 684, and 612 keV) and pure (δ = 0) J = 1 (303, 504, 846, and 1196 keV) transitions, respectively, average 1.01(2) and 0.56 (2), in agreement with the expected values of 1 and ∼0.56. The results for previously known transitions are in good agreement with earlier work [3,4,19].…”

“…Prior to this experiment the highest angular momentum observed in 128 Xe was associated with the proposed 16h state at 5570 keV [19]. In the current work, this is confirmed with a measured R DCO value of 0.89(7) for the 954 keV depopulating transition.…”

“…A J π = 10 + state at 3364 keV feeding the 8 + member of the yrast band was proposed by Lönnroth et al [19]. The current work has identified a band built on this state, which has been extended to a proposed J π = 16 + state at 5967 keV.…”

“…Figure 4 The intrinsic state at 2786 keV was previously assigned as J π = K π = 8 − following a measurement of the g factor by Lönnroth et al [19]. Figure 4(b) shows a spectrum gated by the delayed 287 keV depopulating transition in the earlydelayed matrix, where a complex band structure is identified (see Fig.…”