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

Abstract

The processes of production of fragments with Z greater than or equal to 8 in the interaction of 12.7 GeV He-4 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 GT 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 less than or equal to Z less than or equal to 20 have been determined for the various reaction mechanisms, and their variation as a function of the target mass has been investigated.