Production of fragments with Z≥ 8 in interaction of 12.7 GeV 4He+U, Pb, Au and Ag: track detector study

Abstract: The processes of production of fragments with Z≥ 8 in the interaction of 12.7 GeV 4He with U, Pb, Au and Ag have been analyzed using the polycarbonate track detector Makrofol. The sandwich technique was used which enables direct observation of multiply charged fragment emission by a single nucleus. The decay channels ending with one, two, or more (three, four) fragments were detected. A classification scheme based on the multiplicity of heavy fragments with Z > 20 was used in order to identify the events belonging to the different reaction channels. The cross sections, excitation energies and multiplicities of intermediate-mass fragments 8 ≤Z≤ 20 have been determined for the various reaction mechanisms, and their variation as a function of the target mass has been investigated.