Photodisintegration of cosmic ray nuclei in galaxies and galaxy cluster   radiation fields
  We present the results of a new calculation for the photodisintegration of ultra-high energy cosmic ray nuclei on soft photon targets. We include all the relevant photodisintegraton processes i.e giant dipole resonance, quasi-deuteron, baryonic resonances and photofragmentation. In particular, for the giant dipole process we use a recent calculation of the giant dipole cross section. We calculate the mean free path for photodisintegration processes for radiation fields that are likely to exist within galaxies and clusters of galaxies. 
T. A. Porter and D. Allard