Fragmentation of 14-N, 16-O, 20-Ne, and 24-Mg Nuclei at 290 to 1000 MeV/nucleon

Abstract: We report fragmentation cross sections measured at 0 deg for beams of 14-N, 16-O, 20-Ne, and 24-Mg ions, at energies ranging from 290 MeV/nucleon to 1000 MeV/nucleon. Beams were incident on targets of C, CH2, Al, Cu, Sn, and Pb, with the C and CH2 target data used to obtain hydrogen-target cross sections. Using methods established in earlier work, cross sections obtained with both large-acceptance and small-acceptance detectors are extracted from the data and when necessary corrected for acceptance effects. The large-acceptance data yield cross sections for fragments with charges approximately half of the beam charge and above, with minimal corrections. Cross sections for lighter fragments are obtained from small-acceptance spectra, with more significant, model-dependent corrections that account for the fragment angular distributions. Results for both charge-changing and fragment production cross sections are compared to the predictions of the Los Alamos version of the Quark Gluon String Model (LAQGSM) as well as the NUCFRG2 and PHITS models. For all beams and targets, cross sections for fragments as light as He are compared to the models. Estimates of multiplicity-weighted helium production cross sections are obtained from the data and compared to PHITS and LAQGSM predictions. Summary statistics show that the level of agreement between data and predictions is slightly better for PHITS than for either NUCFRG2 or LAQGSM.