Wide Angle and Out-Of Correlations in LITHIUM(7) Fragmentation.

Available from UMI in association with The British Library. The reaction mechanisms producing wide angle alpha+t coincidence events in the interaction of 70MeV ^7Li with ^{12}C, ^ {120}Sn and ^{208 }Pb have been investigated. The use of large area Ion Implanted Silicon Strip Detectors allowed the out-of-plane coincidence distributions to be measured simultaneously with the in-plane data. Angular distributions for the inclusive and exclusive alpha-t reaction channel, in and out of the reaction plane, have been measured. The quasi-elastic alpha particle projected energy spectra are presented and compared with the results of a Monte Carlo simulation modelling sequential break-up from the excited states of ^7Li. At larger angular separations between the outgoing fragments the data are inconsistent with this process. A simple plane wave Born approximation calculation was found to give a reasonable fit to the forward angled coincidence events and to reproduce the out-of-plane variation with changing detection angle. An attempt was made to factorise the quasi-elastic angular distributions into the product of the fragment inclusive yields. Whilst this was partly successful for the in-plane data, the out-of-plane data exhibited a significant in -plane enhancement, strongly dependent on the fragment detection angles. This behaviour was predicted from a semi-classical three body kinematic calculation where the forces on the fragments were explicitly calculated at all points along their trajectory.