{sup 48}Ti(n,xnpa{gamma}) reaction cross sections using spallation neutrons for E{sub n} = 1 to 20 MeV

Dashdorj, D ; Mitchell, G E ; Garrett, P E ; Agvaanluvsan, U ; Becker, J A ; Bernstein, L A ; Cooper, J R ; Hoffman, R D ; Younes, W ; Devlin, N ; Fotiades, N ; Nelson, R O

Lawrence Livermore National Laboratory

关键词: Data Analysis;    Fission;    Excitation Functions;    Dead Time;    Thickness;   

DOI  :  10.2172/15015860
RP-ID  :  UCRL-TR-209474
RP-ID  :  W-7405-ENG-48
RP-ID  :  15015860

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来源: UNT Digital Library

【 摘 要 】

{gamma}-ray excitation functions have been measured for the interaction of fast neutrons with {sup 48}Ti (neutron energy from 1 MeV to 250 MeV). The Los Alamos National Laboratory spallation neutron source, at the LANSCE/WNR facility, provided a ''white'' neutron beam which is produced by bombarding a natural W target with a pulsed proton beam. The prompt-reaction {gamma} rays were measured with the large-scale Compton-suppressed Ge spectrometer, GEANIE. Neutron energies were determined by the time-of-flight technique. Excitation functions were converted to partial {gamma}-ray cross sections, taking into account the dead-time correction, the target thickness, the detector efficiency, and neutron flux (monitored with an in-line fission chamber). The data analysis is presented here for neutron energies between 1 to 20 MeV. Partial {gamma}-ray cross sections for transitions in {sup 47,48}Ti, {sup 48}Sc, and {sup 45}Ca have been determined. These results are compared to Hauser-Feshbach predictions calculated using the STAPRE code, which includes compound nuclear and pre-equilibrium emission. The partial cross sections for {gamma} rays, whose discrete {gamma}-ray cascade path leads to the ground state in {sup 48}Ti, {sup 47}Ti, {sup 48}Sc, and {sup 45}Ca have been summed to obtain estimates of the lower limits for reaction cross sections. Partial cross sections for unobserved {gamma}-rays are predicted from the STAPRE code. These lower limits are combined with Hauser-Feshbach calculations to deduce {sup 48}Ti(n,n'){sup 48}Ti, {sup 48}Ti(n,2n){sup 47}Ti, {sup 48}Ti(n,p){sup 48}Sc, and {sup 48}Ti(n,{alpha}){sup 45}Ca reaction channel cross sections.