Reactions induced beyond the dripline at low energy by secondary beams

Reactions induced on protons at low incident energy (3.5 MeV/n) were measured with a 8He beam accelerated by Spiral at Ganil. The particles were detected in the active target Maya, filled with C4H10 gas. The beam was stopped in the detector, so energies from incident beam energy down to detector threshold were covered. Proton elastic scattering, one neutron pick-up (p, d) and (p, t) reactions were observed. In the (p, d) reaction very high cross-sections of the order of 1barn were observed, that could be reproduced using a direct reaction formalism. This is the first time that this strong increase of transfer reaction cross-sections at very low energy predicted for loosely bound systems was observed. Spectroscopic factors are in agreement with a simple shell model configuration. No evidence for a low lying excited state in 7He was found

Isomers in neutron-rich A approx 190 nuclides from 208Pb fragmentation

Relativistic projectile fragmentation of 208Pb has been used to produce isomers in neutron-rich, A appro 190 nuclides. A forward-focusing spectrometer provided ion-by-ion mass and charge identification. The detection of γ-rays emitted by stopped ions has led to the assignment of isomers in 188Ta, 190W, 192}Re, 193Re, 195Os, 197r, 198Ir, 200Pt, 201Pt, 202Pt and 203Au, with half-lives ranging from approximately 10 ns to 1 ms. Tentative isomer information has been found also for 174Er,175Er, 185Hf, 191Re, 194Re and 199Ir. In most cases, time-correlated, singles γ-ray events provided the first spectroscopic daa on excited states for each nuclide. In 200Pt and 201Pt, the assignments are supported by γ-γ coincidences. Isomeric ratios provide additional information, such as half-life and transition energy constraints in particular cases. The level structures of the platinum isotopes are discussed, and comparisons are made with isomer systematics