Isotope correlations as a probe for freeze-out characterization: central 124Sn+64Ni, 112Sn+58Ni collisions

124Sn+64Ni and 112Sn+58Ni reactions at 35 AMeV incident energy were studied with the forward part of CHIMERA multi-detector. The most central collisions were selected by means of a multidimensional analysis. The characteristics of the source formed in the central collisions, as size, temperature and volume, were inspected. The measured isotopes of light fragments (3 <= Z <=8) were used to examine isotope yield ratios that provide information on the free neutron to proton densities.Comment: 4 pages, Contribution to 8th International Conference on Nucleus-Nucleus Collisions, Moscow 200

Atomic effects in heavy-ion elastic scattering

Angular distributions of a Pb-208 beam on Pb-208 thin targets at very small angles were measured. The shape of the experimental distribution is not Gaussian, indicating a plural scattering regime rather than multiple scattering. The distribution was well reproduced by a Monte Carlo simulation of the straggling process. For the first time we observed and quantified the influence of the production of electrons during the scattering. This effect was observed in the angular correlation of the scattered Pb-208 nuclei detected in kinematic coincidence and also in the limiting angle of the Pb-208 scattered in a Ag-107,Ag-109 target. This effect introduces a spread in the scattered angle which is of the same order of magnitude as the angular straggling

SEARCH FOR COLOR VAN-DER-WAALS FORCE IN PB-208+PB-208 MOTT SCATTERING

In a high precision experiment, Mott scattering of the Pb-208 + Pb-208 system was measured at E(lab) = 873.40 MeV and 1129.74 MeV with kinematic coincidences for angle pairs around theta(lab) = 30-degrees, 60-degrees and theta(lab) = 45-degrees, 45-degrees. The observed Mott oscillations exhibit an angular shift with respect to pure Mott scattering. A comparison with the angular shift produced by a color van der Waals force including nuclear polarizability, vacuum polarization, relativistic effects, and electronic screening provides a new upper limit for the strength of this force. Influence of atomic effects other than screening were identified for the first time

THE HIGH-PRECISION MEASUREMENT OF PB-208+PB-208 MOTT SCATTERING AT ENERGIES UNDER THE COULOMB BARRIER - THE OBSERVATION OF NEW ATOMIC EFFECTS

In a high precision experiment, Mott scattering of the Pb-208+Pb-208 and elastic scattering of the Pb-208+U-238 systems was measured at 6 energies near the Coulomb barrier with kinematic coincidences for angle pairs at theta(lab)=30 degrees, 60 degrees. The relative laboratory angle between scattered and recoiling nuclei, measured with an absolute precision of 0.003 degrees provides a measurement of the reaction kinematics and the energy loss in the reaction. The binding energy of internal shells of the quasiatoms formed during the collision can be measured in this way