Radiochemical studies of recoil products in the interaction of 28 GeV and 2.2 GeV protons with uranium, bismuth and gold

The recoil properties of a number of products (lanthanides, barium, palladium and strontium) formed by the interaction of 28 GeV and 2.2 GeV protons with uranium, gold and bismuth were measured by a radiochemical method, using a thick target-thick catcher arrangement as well as a thin target - thin catcher arrangement. The ranges of neutron-deficient products are considerably lower than the ranges of neutron-excess products. There is a strong decreasing tendency for the kinetic energies of neutron-deficient isotopes if the bombarding energy is increased. The momentum spectra of neutron-deficient products are split up in a spallation-like and a fission-like contribution assuming that

/ √ΔA (mean momentum divided by the mass difference between target and product nucleus) is constant. The contribution of spallation is decreasing with increasing ΔA. The forward-to-backward ratio was used to calculate the average deposition energies of the fissioning nuclei. There is a strong dependence of the deposition energy on the N/Z value of the product with a slope of about - 750 MeV per unit change of N/Z. (author)