Production of ternary events in He-4 + U, Bi and Au reactions at 8.8 GeV

摘要

Events with three fragments with Z >= 8 in the interactions of 8.8GeV He-4 with U, Bi and Au nuclei are examined using the Makrofol polycarbonate track detector. The sandwich technique SU used to enable a direct observation of the multiply charged fragment emSUsion by a single nucleus. Fragments produced in these events are identified and an event-by-event model-free analysSU SU performed in order to separate different production mechanSUms. A classification scheme based on the multiplicity of intermediate-mass fragments 8 <= Z <= 20 SU used in order to identify events belonging to the different reaction channels. In the interactions of He-4 with U, about 70% of ternary events are regSUtered with the multiplicity of intermediate-mass fragments M-IMF(obs) = 0, 1, while in the interactions of He-4 with Au, about 60% of ternary events are regSUtered with M-IMF(obs) = 2, 3. The analysSU shows that these two groups of ternary events are produced by different reaction mechanSUms. The cross-sections and experimental features are determined for the various reaction mechanSUms, and their variation with the target mass has been investigated.