Emission of 3H and 4He particles in the photofission of actinides

The emission of light charged particles (LCP) in the photofission of 233U, 235U, 237Np and 242Pu with 12, 15 and 20 MeV bremsstrahlung was studied. For the identification of the LCP ΔE-E detectortelescopes were used. We have determined the triton and α particle emission probabilities and the characteristics of the kinetic energy distribution of the α particles. Our measurements show that the excitation energy transferred to the compound nucleus essentially doesn't change the emission probability of the LCP. Our results are compared to sf and thermal neutron induced fission results. They are consistent with the idea that the LCP emission probability is correlated to the deformation energy of the system at scission. (author)