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dc.contributor.authorBurgett, Eric A.en_US
dc.date.accessioned2008-06-10T20:41:23Z
dc.date.available2008-06-10T20:41:23Z
dc.date.issued2008-04-03en_US
dc.identifier.urihttp://hdl.handle.net/1853/22624
dc.description.abstractA 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.publisherGeorgia Institute of Technologyen_US
dc.subjectNeutron spectroscopyen_US
dc.subjectUnfoldingen_US
dc.subjectHigh energyen_US
dc.subjectBonner sphere extensionen_US
dc.subjectNeutron spectrometeren_US
dc.subjectBonner sphereen_US
dc.subject.lcshSpectrometer
dc.subject.lcshNeutrons
dc.titleA broad spectrum neutron spectrometer utilizing a high energy Bonner sphere extensionen_US
dc.typeThesisen_US
dc.description.degreeM.S.en_US
dc.contributor.departmentNuclear and Radiological Engineeringen_US
dc.description.advisorCommittee Chair: Hertel, Nolan; Committee Co-Chair: Howell, Rebecca; Committee Member: Wang, Chris C-Ken_US


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