An accelerator test of semi-empirical cross-sections

Experimentally measured yields of isotopes of elements from Mg to K resulting from the fragmentation of Ar-40 are compared with calculated yields based on semiempirical cross-section formulas. Excellent mass resolution is obtained in measurements using a beam of 287 MeV/amu Ar-40 incident on a CH2 target. The resolution is made possible by an Si(Li) detector telescope. Whereas the general agreement between calculation and experiment is good, with an rms difference of approximately 24 percent, attention is called to certain significant differences. It is found that important information for refining the semiempirical calculation of fragmentation cross sections can be obtained from data collected during the calibration of cosmic ray detector systems when such calibrations are performed under suitable conditions.