No abstract

Cross sections and thick-target recoil properties of several Kr and Xe isotopes formed in the interaction of " Th with 0.1S -24 GeV protons have been determined in order to study their variations with mass product and incident energy. High sensitivity mass spectrometry has been used to measure noble gas isotopic composition and concentration. The recoil technique, combined with a mathematical formalism based on the two-step model, permits the determination of some characteristics of the nuclear reactions; i.e. , the range B, the mean kinetic energy ( T ), the observed products and the excitation energy E*, and the residual nucleus after intranuclear cascade. The results are discussed in terms of fission and deep spallation mechanism. Fission contributes noticeably to the formation of neutron-excess products at all incident energies, while deep spallation concerns the most neutron-deficient isotopes at energies beyond 1 GeV. This last mechanism is described in terms of coherent interaction between incident protons and target nucleus.NUCLEAR REACTIONS Measured o. , 28'(F+B) and F/B of various Kr and Xe nuclides formed in interaction of 2 Th with 0.1S -24 GeV protons.

Neutron-irradiated targets of natural magnesium have been analyzed by mass spectrometry in order to determine the excitation functions of neon from the energy threshold up to 20 MeV. Production cross sections of ' Ne isotopes were measured at 5.20, 7.00, 16.20, and 19. 05 MeV.