The measurement of the fragment emission angles in the reactions of <135 MeV/u 12C and 16O in tissue equivalent targets

Different stacks of tissue equivalent targets interleaved with CR-39 nuclear track detectors were irradiated with 135 MeV/u(12)C and O-16 ions. After track etching and measurement by an automatic image analysis system, a method of trajectory tracing was applied. The trajectories of particles were reconstructed using a pattern-matching method based on a comparison of relative track coordinates. Fragmentation products have a lower charge and can be clearly distinguished by their smaller track sizes. The track positions within the individual trajectory are additionally fitted to a straight line, from which we can determine the direction of the traversing ion within a path of a few mm. We performed an angular distribution study of the fragments, which we compared to simulation results obtained by a simple particle emission model. For the fitted parameters the model showed agreement within the margins of error but failed to describe the energy dependence and thus should be further improved and upgraded. (C) 2003 Elsevier Ltd. All rights reserved.