Total interaction cross sections have been measured for 8Li on C and Pb targets, for 9Li on C, Al, Cu, Sn and Pb targets, as well as for 11Li on C, Sn and Pb targets at about 80 MeV/nucleon. In addition, 2n-removal cross sections for 11Li have been extracted. These measurements are used to determine the nuclear and the electromagnetic part of the cross sections for the different projectile-target combinations. The experimental results are compared to different model calculations. These comparisons allow one to draw conclusions on the matter density distribution of the neutron-rich lithium isotope 11Li. By comparing our data on the electromagnetic dissociation of 11Li with all the other data available in the literature, we are able to put constraints on the dipole-strength distribution in 11Li.

Total charge-changing cross sections have been measured for8Li on C and Pb targets, for9Li on C, Al, Cu, Sn and Pb targets, as well as for11Li on C, Sn and Pb targets at about 80 MeV/nucleon. These data are compared to measured total reaction cross sections and Glauber-type calculations using Hartree-Fock density distributions. These comparisons allow to draw conclusions on the proton density distribution of the neutronrich lithium isotopes. The results show that even for the most exotic nucleus11Li the proton distribution is only very weakly influenced by the long tail in the neutron density distribution already established in several experiments.

Searches for new radioactivities at the drip line have been conducted at GANIL. The decay modes of Ar-31 and Ti-39 have been investigated. The beta-delayed three proton decay is observed for the first time in Ar-31. Ti-39, which was a very good candidate for the direct 2p emission is found to be a beta-delayed particle emitter.

The different beta-delayed particle-decay modes of 31Ar are investigated by means of a new silicon-detector telescope. Identification of beta-delayed two-proton decay, and beta-delayed three-proton decay observed for the first time, is made possible by Monte Carlo simulations of the detector response. Other beta-delayed single-proton branches are also investigated, and none of the energetically allowed beta-alpha and beta-p-alpha-decay modes are found. Finally, the results of this experiment are compared to shell-model calculations.

Neutron-deficient isotopes with Z=21 to 26 have been produced as projectile-like fragments of an intense 58Ni GANIL beam of 69 MeV/nucleon. The nuclei selected by the upgraded LISE3 spectrometer were identified and implanted in a silicon detector telescope. The 43Cr, 47Fe and 46Fe isotopes were identified for the first time whereas 45Fe, 45Mn, 44Mn and 42V were not observed, indicating probable instability of these nuclei against particle emission. Measurements of the half-lives of 43Cr and 46Mn have been performed and the analysis of their measured beta-delayed proton spectra has given, through the isobaric multiplet mass equation, an empirical estimation of their masses. Half-lives of 44Cr, 43V, 47Fe and 46Fe have also been measured. A discussion of various mass predictions for nuclei at the proton drip-line is given.

Total interaction cross sections have been measured for8Li on C and Pb targets, for9Li on C, Al, Cu, Sn and Pb targets as well as for11Li on C, Sn and Pb targets. For each beam, we also used a plastic scintillator as target. The measurements with the scintillator targets are used to extract reduced nuclear radii of the lithium isotopes. These radii are then used for the calculation of the nuclear part of the total cross section for the other targets. The total electromagnetic-dissociation (EMD) cross sections have been deduced and are compared to different models. A strong target-charge-dependent EMD cross section is measured for11Li reaching 2.96 −0.82 +0.84 b for the Pb target. In the9Li case, a large EMD cross section for high-Z targets has been observed which amounts to 0.75 ± 0.45 b for the Pb target. The EMD cross sections of both,9Li and11Li, may be understood by the giantdipole-resonance model.

The stopping powers of eleven gaseous media have been measured for 20–85 MeV/u O, 25–60 MeV/u Ar, 20–40 MeV/u Kr and 25–30 MeV/u Xe ions. The experimental method consists of measuring the energy loss of ions traversing a given thickness of gas contained in a gas cell. The energy measurements are performed using a magnetic spectrometer (LISE). The pressure and temperature of the gases are directly measured by appropriate probes. The stopping powers are thus determined with an accuracy of ± 2% to ± 4%. From the comparison of these data with the stopping powers of solids previously measured, the magnitude of the gas-solid effect is estimated. This effect is still observed for 25 MeV/u Xe and vanishes for lighter projectiles at higher energy, when they tend to be fully stripped.

18C has been produced as a projectile fragment in the interaction of a 60 MeV/u 22Ne beam with a thick beryllium + carbon target. Using the LISE spectrometer of GANIL tuned according to the PFIS method allowed an unprecedented measurement of its β-delayed γ spectroscopy, along with redetermination of half-life and β-neutron branching ratio. A partial decay scheme is proposed. A comparison with theoretical predictions provides a qualitative understanding of the decay of 18C.

The neutron-deficient isotopes 39Ti and 40Ti have been produced as fragments of 58Ni projectiles at 65 MeV per nucleon. Decay by β-delayed charged-particle emission has been observed for both of them with half-lives of 26−7+8 ms for 39Ti and 56−12+18 ms for 40Ti. No evidence for direct two-proton emission from 39Ti was obtained. The conditions that would make such a new radioactive mode possible are discussed.

The stopping powers of ten solid media (nine elements from Be to Au and mylar) have been measured for 25–45 MeV/u Kr and 25 MeV/u Mo and Xe ions. The accuracy in stopping power determinations is ± 1–2%. In addition, the charge state distributions at equilibrium of Kr, Mo, Xe ions exiting Be, Al and Au targets have been determined. Average charge states Q ̄ have been deduced. For Kr ions exiting any target, a semi-empirical expression has been obtained to predict the mean charge Q ̄ in a large energy domain (4–50 MeVu). The stopping power data have been compared with a scaling relative to He 2+ ion stopping powers, assuming fully stripped ions inside the degraders. Effective charge parameters γ have been derived and compared with the ionization degree Q ̄ /Z 1 . Information concerning the emission of Auger electrons by ions exiting targets has been obtained. The stopping power data have also been compared with values from Ziegler (1980). Discrepancies are observed for light (Be) and heavy media (Ta-Au). A comparison has been made with the very recent semi-empirical calculations from Hubert et al. (1989). Excellent agreement is found with experimental data for all projectiles and media.

Stopping powers and ranges are tabulated for all ions of atomic number 2 ≤ Z ≤ 103 in the energy region 2.5 ≤ EA ≤ 500 MeV/u for 36 solid materials. The calculations use stopping powers for α particles and a new parameterization for the heavy-ion effective charge which is deduced from a set of about 600 experimental stopping-power values covering an energy range from 3 to 90 MeV/u for 15 incident heavy ions and 18 solid stopping materials.

Using the magnetic spectrometer SPES I at SATURNE, energy-loss measurements have been performed for projectiles of 40Ar (401 MeV/u), 36P (362 MeV/u), 15N (149 MeV/u), 11Li (131 MeV/u) and 8Li, 9Li (130 MeV/u) in carbon, aluminum and lead targets. The experimental results are compared to calculations based on a modified relativistic Bethe formula and to a semiempirical formula using a Z2 scaling law for the stopping power and an effective charge parametrization for the heavy ions.

The stopping powers of twelve gaseous media have been measured for Ne and Ar ions in the energy range 2–13 MeV/u. The experimental method consists in measuring the ion beam energy before and after its slowing down in a given thickness x of gas. This thickness is derived from the simultaneous measurements of the energy loss of 8.78 and 6.06 MeV alpha particles in the same gas cell.

The beta-gamma spectroscopic study of22O is presented. This nucleus, produced as a projectile-like fragment from the interaction of a 60 MeV/n40Ar beam with a Be target, has been separated by the LISE spectrometer. Several gamma rays from22O decay have been observed, from which a half-life of (2.25±0.15)s has been determined. Accurate excitation energies have been deduced for several states in22F. A partial beta decay scheme of22O has been established. Experimental results have been compared with shell model calculations.

A semi-empirical procedure to compute heavy ion electronic stopping powers is presented. The calculations use stopping powers for alpha particles and a new parameterization for the effective charge which is deduced from a set of about 600 experimental stopping power values covering an energy range from 3 to 80 MeV/A for 15 incident heavy ions and 18 solid stopping materials.