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99,101,103Ru were populated in (α,nγ) reactions. Half-lives in the sub-nanosecond range were measured by using the ROSPHERE γ ray array. Results for the first 3/2+ states in 99,101Ru and the first 7/2+ states in 99,101,103Ru were obtained and are discussed within the Rigid-Triaxial-Rotor-plus-Particle model. Calculated level energies are in good agreement with the experimental level scheme but the model fails in reproduction of some of the reduced transition probabilities. This is, most probably, due to wave function admixtures which are outside the model space. [ABSTRACT FROM AUTHOR]

fast-timing method to determine lifetimes of nuclear states in the sub-nanosecond domain is presented. It is based on in-beam measurements of triple-gamma coincidences in heavy-ion fusion-evaporation reactions, performed with an array of HPGe and LaBr:Ce detectors. The high-energy resolution HPGe detectors are used to define de-exciting cascades, while the fast LaBr:Ce detectors are used to determine the decay time spectra of selected levels fed by these cascades. A special method to treat the time information of an array of fast detectors is employed in order to fully use the efficiency of the array. Two measurements are presented to illustrate the method: a re-determination of the known half-life $\ensuremath T_{1/2}=0.7$ ns of the $\ensuremath E_x=205$ keV, $\ensuremath J^{\pi}=7/2^+$ level in Cd (test experiment), and the determination of a half-life $\ensuremath T_{1/2}=47$ ps for the $\ensuremath E_x=367$ keV, $\ensuremath J^{\pi}=3/2^+$ state of Tl . [ABSTRACT FROM AUTHOR]

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 f5/2 , p3/2 , p1/2 , and g9/2 valence orbitals. Effective spin, orbital, and “tensor” g -factors were determined empirically for protons and neutrons in the considered configuration space. [ABSTRACT FROM AUTHOR]

We present a new study of the low-lying states in 124Te nucleus by γ-ray spectroscopy following 124Iβ+/ε decay. The β radioactive sources were produced in the 124Te(p, n)124I reaction induced by 11 MeV protons, delivered by the Bucharest FN Tandem Accelerator. The γ-rays were measured in a low background area with three large volume HPGe detectors. A total number of 276 milion double coincidence events were recorded in a six-day run. Most of the gamma line intensities previously measured were confirmed with improved accuracy and several gamma lines were obtained for the first time. Our results, combined with those from a recent (n, γ) study are compared with the predictions of the E(5) critical point symmetry model and numerical IBA-1 model calculations at the critical point of the U(5)–O(6) phase transition. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

High-spin states in the 96Tc nucleus have been studied with the reactions 82Se(19F,5nγ) at 68 MeV and Zn(36S,αp xn) at 130 MeV. Two γ-ray cascades (irregular bandlike structures) have been observed up to an excitation energy of about 10 MeV and spin 21-22?. [ABSTRACT FROM AUTHOR]

The lifetimes of twelve low spin excited states in [SUP73]As, below 2 MeV excitation, have been measured with the DSA method in the 73Ge(p,n&gama;) reaction. The existing data (energy levels, electromagnetic moments, transition probabilities and branching ratios, one-nucleon transfer spectroscopic factors) are discussed in the frame of multi-shell interacting boson-fermion model calculations. A good agreement is obtained for a large number of levels. [ABSTRACT FROM AUTHOR]