Half-life of the yrast 2

The half-life of the yrast I π = 2+ state in the neutron-rich nucleus 188W has been measured using fast-timing techniques with the HPGe and LaBr3:Ce array at the National Institute of Physics and Nuclear Engineering, Bucharest. The resulting value of t1/2 = 0.87(12) ns is equivalent to a reduced transition probability of B(E2; 2+ 1 → 0+ 1 ) = 85(12) W.u. for this transition. The B(E2; 2+ 1 → 0+ 1 ) is compared to neighboring tungsten isotopes and nuclei in the Hf, Os, and Pt isotopic chains. Woods-Saxon potential energy surface (PES) calculations have been performed for nuclei in the tungsten isotopic chain and predict prolate deformed minima with rapidly increasing γ softness for 184–192W and an oblate minimum for 194W

High-spin states in the \chem{^{97}Tc} nucleus

High-spin states in the $^{97}$Tc nucleus have been studied by in-beam $\gamma$-ray spectroscopy with the reaction $^{82}$Se($^{19}$F,4n$\gamma$) at 68 MeV incident energy. Excited states have been observed up to about 8 MeV excitation and spin 43/2$\hbar$. The observed level scheme is compared with results of shell model calculations

Gamma-ray spectroscopy of the nucleus

Gamma-ray coincidence techniques are used to determine new level structures in the N = 81 nucleus 139Ce, at low spins and excitation energies with the 139La(p, nγ) reaction at 5.0 and 6.0MeV incident energy, and at high spins with the 130Te(12C, 3nγ) reaction at 50.5MeV, respectively. Lifetime determinations are also made in the (p, nγ) reaction with the centroid DSA method. The observed level structures are discussed by comparison with existing calculations and with those in the neighbouring nucleus 140Ce

High-spin states in the 96Tc{^{96}Tc} nucleus

High-spin states in the $^{96}$Tc nucleus have been studied with the reactions $^{82}$Se($^{19}$F,5n$\gamma$) at 68 MeV and Zn($^{36}$S,$\alpha$p$x$n) at 130 MeV. Two $\gamma$-ray cascades (irregular bandlike structures) have been observed up to an excitation energy of about 10 MeV and spin 21-22$\hbar$

Isomerism of low-lying states in

Low-energy isomeric states of 86Y were populated in the reaction 73Ge + 16O at 57MeV and were investigated by means of delayed n$\gamma$ and $\gamma$ $\gamma$ coincidences. A half-life of 70(7)ns was measured for the 5- state at 208keV, yielding an exceptionally small B(M1) value of 2.0(7)×10-5 W.u. and a B(E2) value of 0.34(+24 -13) W.u. For the other three known isomeric states at 218, 243, and 302keV, the half-lives extracted from the present experimental data are in very good agreement with previous measurements. Given the newly observed isomeric character of the 5- 208keV state, the re-analysis of earlier experimental data on the 302keV isomer led to a new spin-parity assignment, 6+, for this state. In addition, this re-evaluation provided two g -factors, -0.083(3) and +0.63(2) , for the 208 and 302keV states, respectively. The results are discussed in terms of spherical-shell model calculations performed with a truncated space of configurations built on the f 5/2 , p 3/2 , p 1/2 , and g 9/2 valence orbitals. Effective spin, orbital, and “tensor” g -factors were determined empirically for protons and neutrons in the considered configuration space

Gamma-ray fast-timing coincidence measurements from the (18)O+(18)O fusion-evaporation reaction using a mixed LaBr(3)-HPGe array

We report on a gamma-ray coincidence analysis using a mixed array of hyperpure germanium and cerium-doped lanthanum tri-bromide (LaBr(3):Ce) scintillation detectors to study nuclear electromagnetic transition rates in the pico-to-nanosecond time regime in (33,34)P and (33)S following fusion-evaporation reactions between an (18)O beam and an isotopically enriched (18)O implanted tantalum target. Energies from decay gamma-rays associated with the reaction residues were measured in event-by-event coincidence mode, with the measured time difference information between the pairs of gamma-rays in each event also recorded using the ultra-fast coincidence timing technique. The experiment used the good full-energy peak resolution of the LaBr(3):Ce detectors coupled with their excellent timing responses in order to determine the excited state lifetime associated with the lowest lying, cross-shell, I(π)=4(-) "intruder" state previously reported in the N=19 isotone (34)P. The extracted lifetime is consistent with a mainly single-particle M2 multipolarity associated with a f(7/2)→d(5/2) single particle transition