Design and optimization of 6li neutron-capture pulse mode ion chamber

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dc.contributorBraby, Les A.
dc.creatorChung, Kiwhan
dc.date.accessioned2010-01-15T00:12:23Z
dc.date.accessioned2010-01-16T01:12:51Z
dc.date.accessioned2017-04-07T19:55:49Z
dc.date.available2010-01-15T00:12:23Z
dc.date.available2010-01-16T01:12:51Z
dc.date.available2017-04-07T19:55:49Z
dc.date.created2008-08
dc.date.issued2009-05-15
dc.description.abstractThe purpose of this research is to design and optimize the performance of a unique, inexpensive 6Li neutron-capture pulse-mode ion chamber (LiPMIC) for neutron detection that overcomes the fill-gas contamination stemming from outgas of detector components. This research also provides a demonstration of performance of LiPMICs. Simulations performed with GARFIELD, a drift-chamber simulation package for ion transport in an electrostatic field, have shown that argon-methane mixtures of fill-gas allow maintenance of electron drift velocity through a surprisingly wide range of fill-gas content. During the design stage of LiPMIC development, the thicknesses of lithium metallization layer, the neutron energy conversion site of the detector, and the thickness of neutron moderator, the high-density polyethylene body, are optimized through analytical and MCNPX calculations. Also, a methodology of obtaining the suitable combination of electric field strength, electron drift velocity, and fill-gas mixtures has been tested and simulated using argon-methane gas mixtures. The LiPMIC is shown to have comparable efficiency to 3He proportional counters at a fraction of cost. Six-month long baseline measurements of overall detector performance shows there is a 3% reduction in total counts for 252Cf sources, which provides a good indicator for the longevity of the detector.
dc.identifier.urihttp://hdl.handle.net/1969.1/ETD-TAMU-3022
dc.language.isoen_US
dc.subjectradiation detector
dc.subjectthermal neutron
dc.titleDesign and optimization of 6li neutron-capture pulse mode ion chamber
dc.typeBook
dc.typeThesis

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