Development of LASSA: A large area silicon strip array for nuclear reaction studies and investigation of mid-velocity fragment emission in cadmium-114 + molybdenum-92,98 reactions at E/A = 50 MeV

A new high-resolution, low-threshold, charged-particle detector array, LASSA, was developed for the detection of isotopically resolved fragments emitted in intermediate energy heavy-ion reactions. This array of nine telescopes utilizes silicon-strip technology and a novel method for mounting the silicon detectors. Each telescope of the array consists of a Si-Si-CsI(TI) stack and provides isotopic resolution for Z ≤ 8 with good angular (&thetas; _lab ≤ 0.9°) and energy resolution.; Investigation of peripheral collisions in the reaction 114Cd + 92Mo at E_lab/A = 50 MeV reveals that fragment emission aft of the projectile-like fragment (PLF) is enhanced relative to emission forward of the PLF. Examination of events in which the PLF undergoes binary decay indicates the existence of two components. Based upon the relative magnitude of the velocity of the two decay products or their relative velocity, one can separate these two components. One of these two components can be understood as the standard statistical decay of the excited PLF. Comparison of the charge correlations selected on the relative magnitudes of two fragment velocities indicates that while for the standard decay component the sizes of the two fragments involved in the binary split are anti-correlated, for the second component the size of the smaller fragment is independent of the size of the larger fragment. The non-standard component also exhibits a different Z distribution as compared to the standard component. Characteristics of both components are explored.