PRODUCTION OF FRAGMENTS WITH Z-GREATER-THAN-OR-EQUAL-TO-8 IN INTERACTION OF 12.7 GEV HE-4- TRACK DETECTOR STUDY(U, PB, AU AND AG )

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 be en analyzed using the polycarbonate track detector Makrofol. The sandw ich technique was used which enables direct observation of multiply ch arged fragment emission by a single nucleus. The decay channels ending with one, two, or more (three, four) fragments were detected. A class ification scheme based on the multiplicity of heavy fragments with Z > 20 was used in order to identify the events belonging to the differen t reaction channels. The cross sections, excitation energies and multi plicities of intermediate-mass fragments 8 less than or equal to Z les s than or equal to 20 have been determined for the various reaction me chanisms, and their variation as a function of the target mass has bee n investigated.