The surrogate ratio method has been tested for (p,d) and (p,t) reactions on uranium nuclei. 236U and 238U targets were bombarded with 28-MeV protons and the light ion recoils and fission fragments were detected using the Silicon Telescope Array for Reaction Studies detector array at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The (p,df) reaction channels on 236U and 238U targets were used as a surrogate to determine the σ[236U(n,f)]/σ[234U(n,f)] cross-section ratio. The (p,tf) reaction channels were also measured with the same targets as a surrogate for the σ[235U(n,f)]/σ[(233U(n,f)] ratio. For the (p,df) and (p,tf) surrogate measurements, there is good agreement with accepted (n,f) values over equivalent neutron energy ranges of En=0–7 MeV and En=0–5.5 MeV, respectively. An internal surrogate ratio method comparing the (p,d) and (p,t) reaction channels on a single target is also discussed. The σ[234U(n,f)]/σ[233U(n,f)] and σ[236U(n,f)]/σ[235U(n,f)] cross-section ratios are extracted using this method for the 236U and 238U targets, respectively. The resulting fission cross-section ratios show relatively good agreement with accepted values up to En∼5 MeV.
Copyright © 2012 The American Physical Society. This article first appeared in Physical Review C 85, no. 2 (February 21, 2012): 024613: 1-24613: 8. doi:10.1103/PhysRevC.85.024613.
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Hughes, R., C. Beausang, T. Ross, J. Burke, N. Scielzo, M. Basunia, C. Campbell, R. Casperson, H. Crawford, J. Escher, J. Munson, L. Phair, and J. Ressler. "Utilizing (p,d) and (p,t) Reactions to Obtain (n,f) Cross Sections in Uranium Nuclei Via the Surrogate-Ratio Method." Physical Review C 85, no. 2 (February 21, 2012): 024613: 1-24613: 8. doi:10.1103/PhysRevC.85.024613.