Search

Neutron-rich light nuclei near the neutron drip line have attracted much attention in recent years as they feature a particular nuclear structure, namely an extended distribution (so-called halo) of the valence neutrons surrounding a compact nuclear core. Elastic proton scattering is known as a suitable technique for exploring the nuclear matter distributions in the stable nuclei. It was successfully employed at GSI also for the radioactive nuclei 6,8He and 8,9,11Li [1–3]. The experimental technique of inverse kinematics was applied using radioactive beams with energies near 700 MeV/u. The elastic differential cross section for small-angle scattering (3° ≤ θCM ≤ 10°) was deduced from the data taken with the ionization chamber IKAR, as an active target, and a forward spectrometer. The method has been demonstrated to be very effective for obtaining valuable information on the nuclear matter distribution in the halo nuclei under investigation, such as 6He, 8He and 11Li. The previous measurements at small momentum transfer have been highly sensitive on the nuclear sizes and the radial distributions of the nuclear matter density. Recently, a novel experimental approach has been accomplished with the aim to deduce the differential p6,8He cross sections for larger angles (10≤ ± θCM ≤ 30°) that correspond to a higher momentum transfer which covers the region of the first diffraction minimum.

Existence of a new feature in fragment mass-energy distribution is reported. Careful analysis of the data obtained in the reaction 238U + 40Ar (275 MeV) shows that small but statistically significant ripples visible already in the gross mass spectrum come from extended and regular 2D patterns in the TKE vs. mass matrix. Intensity distributions of these patterns coincide with the location of heavy clusters such as 78Ni, 108Mo, or 132Sn. Presumably, the observed patterns show the dominant trajectories in the elongation vs. mass-asymmetry space of the decaying system. This information, unknown in the past, can shed a new light even on the previously well-studied reactions.

The yield of light fission products from the reaction 241Am(2nth,f) were measured as function of mass A, atomic number Z, and kinetic energy E, using the recoil mass separator LOHENGRIN of the Institute Laue-Langevin at Grenoble. Mass distributions summed over ionic charge states were determined within the mass range 85 ≤ A ≤ 110 at seven kinetic energies between 86.9 and 117.0 MeV. For the same range of masses, nuclear charge distributions were measured for five energy values between 98.0 and 116.2 MeV. From the data, we have also evaluated the energy integrated nuclear charge and mass yields, as well as isotonic and isotopic yields and their odd-even effects.

Basic features of scintillation detectors based on the luminescence of noble gases and relevant gas mixtures are traced in the light of known radio luminescence processes The application of this detection regime to heavy ions is outlined and experimental results are reported.