R. Elmér

Flow effects in intermediate-energy nuclear collisions

Abstract Central events in 36 Ar and 16 O induced reactions on Ag/Br a 65±15 MeV/nucleon and 210±10 MeV nucleon bombarding energy, respectively, have been analysed. For the 36 Ar induced reaction a flow energy of about 3 MeV/nucleon has been deduced for intermediate mass fragments. Evaporative processes can be ruled out as the origin of the intermediate mass fragments since the emission time is much larger than the expansion time estimated from the flow analysis.

Neutron-proton interferometry in 30A MeV40Ar+197Au collisions

Abstract Neutron-proton correlation functions in 30A MeV 40 Ar + 197 Au , 12 C , CH 2 reactions have been measured. In contrast to the nn and pp correlations, which exhibit the shape expected from quantum symmetrization effects and nuclear+Coulomb (pp) final-state interaction, the np function shows much less correlation strength. This may be due to Coulomb repulsion on the proton and/or to a larger effective spin than expected. Selecting high energy nucleons strengthens both the np and pp correlations.

A CCD-based system for analysis of nuclear collisions in photographic emulsion

Abstract A CCD-based system for reading and analyzing nuclear emulsion pictures is described. Profile and area measurements on tracks produced by stopping nuclei with charge 1 to 79 are presented. The charge resolution is ranging from ΔZ/Z ≤ 0.6 at a residual range of 100 μm to ΔZ/Z ≤ 0.3 at 200 μm for all charges.

A compact range telescope for K+ measurements

Abstract We present range telescopes for measurements of low energy K + mesons together with first in-beam results. The hardware trigger, based on the observation of the μ + from the K + → μ + + ν μ decay channel, is designed for subthreshold hadron-nucleus and heavy ion reactions, where the kaon fraction of the total number of charged particles is ⪡ 10 −4 . The geometrical efficiency is ∼15% and the total efficiency ∼4% for K + registration in the present version of the detector.

Experimental isotopic effects in comparison to statistical prescriptions for fragment production in 32A MeV and 14A MeV 14N + 112,124Sn reactions

Results on isotopic effects in the production of light fragments in reactions of 14A and 32A MeV 14N ions with 112Sn and 124Sn are presented. The data are discussed in the frameworks of classical Weisskopf evaporation and an alternative Fermi gas prescription. The source isospin dependence of the production rates is consistent only with the latter prescription. It is emphasized that similar data from p-nucleus reactions and from projectile-like fragments in 40Ar induced reactions behave in the same way.