G. Marguier

Production of isomeric44V and42Sc in high energy heavy ion reactions

Beta-coincidentγ-rays were measured from implanted44V and42Sc nuclei. These were selected after58Ni+nickel reactions by means of the LISE3 spectrometer at GANIL. The production of the isomeric states was identified by detecting their typicalβ-delayedγ-ray cascades. From the intensities of the detectedγ-lines the ratio between isomer and ground-state production of44V follows to be 1 to 3.0(4).

TheN=83 nucleus149Dy from Gamow-Teller decay of its 11/2− and 1/2+149Ho parents

A high-sensitivityγ-spectroscopic study of the149Hoπh11/2 andπs1/2β-decays using mass separated sources has located dominant 0+ → 1+ GT decay strength associated with decay of pairedh11/2 protons, leading to 3п-states in the149Dy daughter nucleus. In theirγ-decay low-lying149Dy levels characteristic of anN=83 nucleus are excited. They include theνf7/2,νp3/2,νh9/2 andνp1/2 single particle- and theνs12/−1 andνd32/−1 two-particle one-hole states, as well as the νf7/2 × 3− andνf7/2 × 2+ particle-phonon multiplets. A synopsis is given of these excitations in theN=83 isotones from149Nd to153Yb. The149Dy GT decay strength is discussed in terms of the147Tb82 and148Dy82 decays. The strength function results are also compared with independent149Ho 11/2− decay data from the literature based on totalγ-ray absorption measurements.

Gamow-teller strength and particle-phonon states in149Dy from decay of its 11/2− and l/2+149Ho parents

Studies of the149Ho 11/2− and 1/2+ GT-decays using on-line mass separation have established in the N=83149Dy nucleus the single neutron excitations below 1.8 MeV and members of the νf7/2×3− and νf7/2×2+ particle-phonon multiplets. Quantitative analysis of the GT-decay strength to149Dy 1qp- and 3qp-states is made in terms of the strength values measured in149Dy0 and147Tb11/2− decay.

Gamow‐Teller beta decay of 29–31Na comparison with shell‐model estimates

Gamma rays and delayed‐neutron processes subsequent to beta decay of the neutron‐rich 29–31Na isotopes are studied in singles an coincidence mode with mass‐separated sources at ISOLDE. Improved level schemes are presented for mass 29 and 30, whose features substantially agree with shell‐model predictions. The deduced Gamow‐Teller strengths are discussed as well as the occurrence of negative parity intruder states in the daughter nuclei.

Experimental mass excess of 49,50K and 40,42Cl

Detection of the β–decay of fission fragments produced from 600 MeV proton induced fission of a uranium carbide target has been used to measure the mass excess of 49,50K and 40,42Cl. The experimental data is presented. (AIP)