{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/32904"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/32904","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"Relation of electron scattering cross-sections to drift measurement in noble gases","abstract":"We investigate the classic \"inverse problem\" of extracting collision and scattering cross sections from measurements of electron swarm behavior. A Monte Carlo technique for simulating electron motion through a gas of isotropic scatterers is presented, providing a simplified version of Biagi's MAGBOLTZ algorithm. Using this Monte Carlo software, we examine the thermalization of electron swarms, focusing on their drift velocity and informational entropy, providing justification for a set of analytic expressions for drift measurements which are valid in the hydrodynamic regime. These expressions are then used to estimate the ⁴He scattering cross section, first by a simple grid interpolation and then through a genetic algorithm (GA). This technique demonstrates that the 4He momentum-transfer cross section in the 0-7 eV range is approximately 6.5 [Angstrom]², with a peak near 2 eV, in agreement with literature values. Empirical cross sections are also presented for Xe and He:CH₄(90:10).","abstract_html":"We investigate the classic "inverse problem" of extracting collision and scattering cross sections from measurements of electron swarm behavior. A Monte Carlo technique for simulating electron motion through a gas of isotropic scatterers is presented, providing a simplified version of Biagi's MAGBOLTZ algorithm. Using this Monte Carlo software, we examine the thermalization of electron swarms, focusing on their drift velocity and informational entropy, providing justification for a set of analytic expressions for drift measurements which are valid in the hydrodynamic regime. These expressions are then used to estimate the ⁴He scattering cross section, first by a simple grid interpolation and then through a genetic algorithm (GA). This technique demonstrates that the 4He momentum-transfer cross section in the 0-7 eV range is approximately 6.5 [Angstrom]², with a peak near 2 eV, in agreement with literature values. Empirical cross sections are also presented for Xe and He:CH₄(90:10).","abstract_has_math":false,"creators":["Stacey, Blake (Blake C.)"],"institution":"Massachusetts Institute of Technology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Dept. of Physics.","school":null,"contributors":[],"advisors":["Ulrich J. Becker."],"committee_chairs":[],"committee_members":[],"year":2005,"date_issued":"2005","date_published":"2005","updated_at":"2026-07-22T22:21:19Z","subjects":["Physics."],"languages":["eng"],"rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"rights_urls":["http://dspace.mit.edu/handle/1721.1/7582"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1721.1/32904","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Ulrich J. Becker."]},{"key":"dc:contributor.department","label":"Department","values":["Massachusetts Institute of Technology. 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A Monte Carlo technique for simulating electron motion through a gas of isotropic scatterers is presented, providing a simplified version of Biagi's MAGBOLTZ algorithm. Using this Monte Carlo software, we examine the thermalization of electron swarms, focusing on their drift velocity and informational entropy, providing justification for a set of analytic expressions for drift measurements which are valid in the hydrodynamic regime. These expressions are then used to estimate the ⁴He scattering cross section, first by a simple grid interpolation and then through a genetic algorithm (GA). This technique demonstrates that the 4He momentum-transfer cross section in the 0-7 eV range is approximately 6.5 [Angstrom]², with a peak near 2 eV, in agreement with literature values. Empirical cross sections are also presented for Xe and He:CH₄(90:10)."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["S.B."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Relation of electron scattering cross-sections to drift measurement in noble gases"]}]}],"canonical_facts":{"dc:contributor.advisor":["Ulrich J. Becker."],"dc:contributor.department":["Massachusetts Institute of Technology. Dept. of Physics."],"dc:contributor.other":["Massachusetts Institute of Technology. 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These expressions are then used to estimate the ⁴He scattering cross section, first by a simple grid interpolation and then through a genetic algorithm (GA). This technique demonstrates that the 4He momentum-transfer cross section in the 0-7 eV range is approximately 6.5 [Angstrom]², with a peak near 2 eV, in agreement with literature values. Empirical cross sections are also presented for Xe and He:CH₄(90:10)."],"dc:description.degree":["S.B."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/1721.1/32904"],"dc:language.iso":["eng"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"dc:rights.uri":["http://dspace.mit.edu/handle/1721.1/7582"],"dc:subject":["Physics."],"dc:title":["Relation of electron scattering cross-sections to drift measurement in noble gases"],"dc:type":["Thesis"]},"updated_at":"2026-07-22T22:21:19Z"}