Studying the role of nuclear structure effects in neutron-induced reactions using GEANIE at LANSCE

Conference · Fri Sep 15 04:00:00 EDT 2000

DOI:https://doi.org/10.1016/S0375-9474(00)00667-9· OSTI ID:15004768

Bernstein, L A; Archer, D E; Becker, J A; Garrett, P E; Hauschild, K; McGrath, C A; McNabb, D P; Younes, W; Devlin, M; Drake, D M; Johns, G D; Nelson, R O

Efforts to model and measure absolute neutron-induced reaction cross sections have for the most part been limited by experimental techniques to neutron energies found in reactors and light-ion fusion reactions (i.e., t(d,n){alpha} etc.). This can in large part be attributed to the difficulty involved in making high-flux mono-energetic neutron beams with E{sub n} > 14 MeV. The result has been a lack of guidance for (n,xnypz{alpha}) reaction modeling for E{sub n} > 1-2 MeV. These limitations become particularly exacerbated in nuclei where structure effects (i.e., near shell closures, high deformation etc.) or fission complicates the models. The GEANIE spectrometer at LANSCE/WNR fills this gap in experimental technique by allowing for efficient measurement of neutron-induced {gamma}-ray partial cross sections over a wide range of incident neutron energies (1 < E{sub n} (MeV) < 250). GEANIE consists of 20 Compton-suppressed and 6 unsuppressed hpGe detectors located at the 60{sup o} right beam line at the LANSCE/WNR spallation source. Eleven of the GEANIE detectors are Low Energy Planar Spectrometers (LEPS) with excellent timing and energy resolution. LANSCE/WNR provides a white source of neutrons through the spallation of a tungsten target with an 800 MeV 2-5 {micro}amp beam of protons. Neutron energy is determined from the time-of-flight technique. Early results from GEANIE [Ber98] highlighted the deficiencies in the modeling of neutron-induced reaction modeling on a {sup 196}Pt target. More recently, measurements on a {sup 92}Mo target have identified {gamma}-rays in over 2 dozen reaction products [Gar00a]. In this paper we will present an overview of several recent results from GEANIE, including data on a {sup 92}Mo and two Actinide ({sup 235}U and {sup 239}Pu) targets. The implications of these results for reaction modeling from low to high (E{sub n} < 250 MeV) energy will be presented and plans for future experiments discussed.

• Research Organization: Lawrence Livermore National Lab., CA (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 15004768
• Report Number(s): UCRL-JC-140578
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDES
CROSS SECTIONS
ENERGY RESOLUTION
FISSION
NEUTRON BEAMS
NEUTRONS
NUCLEAR STRUCTURE
NUCLEI
PROTONS
SIMULATION
SPALLATION
SPECTROMETERS
TARGETS
TUNGSTEN