Experimental and calculated scandium threshold reaction cross sections averaged over a {sup 235}U fission neutron spectrum

Journal Article · Sat Nov 01 04:00:00 EST 1997 · Nuclear Science and Engineering

OSTI ID:556635

Suarez, P M; Arribere, M A; Guevara, S R; Kestelman, A J ^[1]

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1. Comision Nacional de Energia Atomica y Univ. Nacional de Cuyo, Bariloche (Argentina)

The reaction cross sections averaged over a {sup 235}U fission neutron spectrum have been measured for the {sup 45}Sc(n,{alpha}){sup 42}K, {sup 45}Sc(n,2n){sup 44}Sc{sup g}, and {sup 45}Sc(n,2n){sup 44}Sc{sup m} threshold reactions. The values found for these cross sections are, respectively: 308 {+-} 16 {mu}b, 27.3 {+-} 1.3 {mu}b, and 22.0 {+-} 1.7 {mu}b, using 111 {+-} 3 mb as the averaged cross section for the {sup 58}Ni(n,p){sup 58}Co{sup m+g} reaction that was used as a standard. To the authors` knowledge, these are the first experimental determinations of the {sup 45}Sc(n,2n){sup 44}Sc{sup g} and {sup 45}Sc(n,2n){sup 44}Sc{sup m} spectrum-averaged cross sections, which were measured using a new method for the case when both the ground and an isomeric state are generated. By fitting with a suitable function the experimental differential cross sections found in the EXFOR data file for each of these reactions, the corresponding spectrum-averaged cross sections have been calculated for nine different analytical representations of the {sup 235}U fission neutron spectrum. This calculation was also performed for the representation based on the Madland-Nix model of prompt fission neutrons. The agreement between calculated and measured values is in general excellent for the {sup 45}Sc(n, {alpha}){sup 42}K low-threshold reaction. However, the agreement is rather poor for the {sup 45}Sc(n,2n) high-threshold reactions, except for two, Maxwellian-type, representations tried.

• OSTI ID: 556635
• Journal Information: Nuclear Science and Engineering, Journal Name: Nuclear Science and Engineering Journal Issue: 3 Vol. 127; ISSN NSENAO; ISSN 0029-5639
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CROSS SECTIONS
NEUTRON REACTIONS
NEUTRON SPECTRA
SCANDIUM 45 TARGET
THRESHOLD ENERGY
TRANSFER REACTIONS
URANIUM 235 TARGET