Fragmentation of 200 and 244 MeV/u carbon beams in thick tissue-like absorbers

Stacks consisting of thin CR-39 sheets sandwiched between thick lucite and water absorbers were perpendicularly bombarded by C-12 ions at 200 and 244 MeV/u. Track radius distributions representing the charge composition of th e fragmented beams were automatically measured by a particle track analysis system. After analysis of the nuclear charge distributions, the total char ge removal cross-sections and elemental production cross-sections of fragme nts with atomic numbers from 5 to 3, were obtained down to the lower energi es (similar to 50 and 100 MeV/u, respectively). It has been found that the measured total charge removal cross-section agrees with theoretical predict ions within -10% and very well with previous experiments in corresponding e nergy regions. Two model calculations for production of B fragment are in g ood agreement with our measured data while a third model overestimates it b y similar to 12%. Theoretical cross-sections for Be and Li fragments differ strongly among the different models and from measured values. (C) 1999 Els evier Science B.V. All rights reserved.