Projectile fragmentation of silicon ions at 490 A MeV

Fragmentation cross sections are essential input parameters for propagation calculations which describe the effect of shielding against cosmic ray hea vy nuclei by the walls of spacecraft or planetary habitat. Cross sections f or the breakup of different elements are needed for different types of targ et material and for a wide range of energy. For this purpose, we have extended our studies of projectile fragmentation. By using stacks containing CR-39 track detectors and targets ranging from CH2 to Pb we have measured total and elemental fragmentation cross sections for fragments with charges Z(F) > 5, for silicon projectiles with energies of 490 A MeV, These new data sets allow us to improve our knowledge about the target and energy dependence of fragmentation cross sections. (C) 2001 Elsevier Science Ltd. All rights reserved.