Title:
A broad spectrum neutron spectrometer utilizing a high energy Bonner sphere extension

dc.contributor.advisor Hertel, Nolan E.
dc.contributor.advisor Howell, Rebecca
dc.contributor.author Burgett, Eric A. en_US
dc.contributor.committeeMember Wang, Chris C-K
dc.contributor.department Nuclear and Radiological Engineering en_US
dc.date.accessioned 2008-06-10T20:41:23Z
dc.date.available 2008-06-10T20:41:23Z
dc.date.issued 2008-04-03 en_US
dc.description.abstract A novel broad spectrum neutron spectrometer has been created to extend the useful energy range of existing neutron Bonner Sphere Spectrometers (BSS). Both an active LiI(Eu) scintillator probe and passive gold foil detector were utilized to extend the energy response of the existing BSS. Above 20 MeV the energy structure for the standard polyethylene BSS are poor because the response functions are not unique. MCNPX was used to investigate several modifications to the BSS system which resulted in the Bonner Sphere Extension (BSE). This cost effective extension uses several concentric spheres of copper, lead, and tungsten heavy metal downscatter materials to extend the useful range of the current BSS from 20 MeV to above 1 GeV. Using both a 3" and 5" inner polyethylene spheres, aluminum shell sets were made with a 1" cavity and filled with the high Z materials for six total sets of spheres. a 12" and 8" polyethylene sphere were also milled to accept the heavy metal spheres. The system was validated at the Los Alamos Neutron Science Center (LANSCE) neutron beam. The system was calibrated at LANSCE for neutrons up to 800 MeV on target 4's 15 degree right flightpath (4FP15R) at 90 meters. Detailed models in MCNPX were made of the BSS, BSE and LANSCE facilities. Fine group responses were made and compared to the unfolded data from LANSCE. A vast improvement over the BSS system alone was seen with reasonable agreement with time of flight data measured at LANSCE and MCNPX calculated neutron spectra. en_US
dc.description.degree M.S. en_US
dc.identifier.uri http://hdl.handle.net/1853/22624
dc.publisher Georgia Institute of Technology en_US
dc.subject Neutron spectroscopy en_US
dc.subject Unfolding en_US
dc.subject High energy en_US
dc.subject Bonner sphere extension en_US
dc.subject Neutron spectrometer en_US
dc.subject Bonner sphere en_US
dc.subject.lcsh Spectrometer
dc.subject.lcsh Neutrons
dc.title A broad spectrum neutron spectrometer utilizing a high energy Bonner sphere extension en_US
dc.type Text
dc.type.genre Thesis
dspace.entity.type Publication
local.contributor.advisor Hertel, Nolan E.
local.contributor.corporatename George W. Woodruff School of Mechanical Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 26003284-0ae0-4887-a127-917eb8923925
relation.isOrgUnitOfPublication c01ff908-c25f-439b-bf10-a074ed886bb7
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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