Thick-target Neutron And. Gamma.-ray Yields Induced by Medium-energy Proton and Deuteron Bombardments


Book Description

Stopping samples of Lucite, Al, Fe, and 238U (Fe, and 238U) were irradiated with 330 MeV deuterons (260 MeV protons). For each target, neutron energy spectra and prompt .gamma.-ray yields were measured using the time-of-flight technique. The detector was a right cylindrical volume of deuterated benzene, 12.5-cm diameter x 7.5-cm long, located at 110° to the incident beam direction. The neutron yield and the prompt .gamma.-ray yield were found to depend upon the atomic number of the target and upon the incident projectile. The measured shape of the neutron energy spectrum was not strongly dependent on either the incident projectile or the target atomic number. A lower limit for absolute neutron yields was also obtained.







Calculated Proton-induced Thick-target Neutron and Radionuclide Yields for E/sub P/ D"100 MeV.


Book Description

Earlier proton-induced thick-target yield calculations have been extended in proton energy range and to additional target elements, using the proton stopping cross section data of Anderson and Ziegler and cross sections modeled with the GNASH code. The targets now described include Be, C, O, Ne, Al, Si, Fe, Co, Ni, Cu, W, Pb and Bi. Thick-target yields are presented for these thirteen targets, with most extending to 100 MeV. 13 refs., 3 figs., 13 tabs.




Thick-target Neutron, Gamma-ray, and Radionuclide Production for Protons Below 12 MeV on Nickel and Carbon Beam-stops


Book Description

Nuclear model calculations using the GNASH code are described for protons below 12 MeV incident on nickel and carbon isotopes, for beam stop design in the Los Alamos Accelerator Production of Tritium Low Energy Demonstration Accelerator (LEDA) project. The GNASH calculations apply Hauser-Feshbach and preequilibrium reaction theories and can make use of pre-calculated direct reaction cross sections to low-lying residual nucleus states. From calculated thin target cross sections, thick target 6.7 MeV and 12 MeV proton-induced production of neutrons, gamma rays, and radionuclides are determined. Emission spectra of the secondary neutrons and gamma rays are also determined. The model calculations are validated through comparisons with experimental thin- and thick-target measurements. The results of this work are being utilized as source terms in MCNP analyses for LEDA.










Development of a Reference Database for Particle Induced Gamma Ray Emission (PIGE) Spectroscopy


Book Description

Ion beam analysis techniques are non-destructive analytical techniques used to identify the composition and structure of surface layers of materials. The applications of these techniques span environmental control, cultural heritage and conservation, materials and fusion technologies. The particle-induced gamma-ray emission (PIGE) spectroscopy technique in particular, is a powerful tool for detecting light elements in certain depths of surface layers. This publication describes the coordinated effort to measure and compile cross section data relevant to PIGE analysis and make these data available to the community of practice through a comprehensive online database.