{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/25562"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/25562","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The effect of neutron irradiation on the density of low-energy excitations in vitreous silica","abstract":"Systematic low-temperature measurements of the thermal conductivity, specific heat, dielectric constant, and temperature-dependent ultrasound velocity have been made on a single piece of vitreous silica. These measurements were repeated after fast neutron irradiation of the material. It was found that the irradiation produced changes of the same relative magnitude in the low-temperature excess specific heat C , the thermal conductivity K, ex and the anomalous temperature dependence of the ultrasound velocity Deltav/v. A corresponding change in the temperature dependent dielectric constant was not observed. It is therefore likely that K and Deltav/v are determined by the same localized excitations responsible for C , but the temperature dependence of the dielectric constant may have a different, though possibly related, origin. Furthermore, a consistent account for the measured C , K, ex and Deltav/v of unirradiated silica is given by the tunneling-state model with a single, energy-dependent density of states. Changes in these three properties due to irradiation can be explained by altering only the density of tunneling states incorporated in the model.","abstract_html":"Systematic low-temperature measurements of the thermal conductivity, specific heat, dielectric constant, and temperature-dependent ultrasound velocity have been made on a single piece of vitreous silica. These measurements were repeated after fast neutron irradiation of the material. It was found that the irradiation produced changes of the same relative magnitude in the low-temperature excess specific heat C , the thermal conductivity K, ex and the anomalous temperature dependence of the ultrasound velocity Deltav/v. A corresponding change in the temperature dependent dielectric constant was not observed. It is therefore likely that K and Deltav/v are determined by the same localized excitations responsible for C , but the temperature dependence of the dielectric constant may have a different, though possibly related, origin. Furthermore, a consistent account for the measured C , K, ex and Deltav/v of unirradiated silica is given by the tunneling-state model with a single, energy-dependent density of states. Changes in these three properties due to irradiation can be explained by altering only the density of tunneling states incorporated in the model.","abstract_has_math":false,"creators":["Smith, Terry Lee"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Anderson, A.C."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-06-29T14:45:40Z","date_published":"2011-06-29T14:45:40Z","updated_at":"2026-07-22T22:25:24Z","subjects":["Neutron irradiation","Low-energy excitations","Vitreous silica","Thermal conductivity","Specific heat","Dielectric constant","Ultrasound velocity"],"languages":["en"],"rights":["Copyright 1979 Terry Lee Smith"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["397342"],"render_values":[{"text":"397342","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/25562","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Anderson, A.C."]},{"key":"dc:creator","label":"Author","values":["Smith, Terry Lee"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-06-29T14:45:40Z","10000-01-01","1979"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Neutron irradiation","Low-energy excitations","Vitreous silica","Thermal conductivity","Specific heat","Dielectric constant","Ultrasound velocity"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1979 Terry Lee Smith"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["397342","http://hdl.handle.net/2142/25562"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Systematic low-temperature measurements of the thermal conductivity, specific heat, dielectric constant, and temperature-dependent ultrasound velocity have been made on a single piece of vitreous silica. These measurements were repeated after fast neutron irradiation of the material. It was found that the irradiation produced changes of the same relative magnitude in the low-temperature excess specific heat C , the thermal conductivity K, ex and the anomalous temperature dependence of the ultrasound velocity Deltav/v. A corresponding change in the temperature dependent dielectric constant was not observed. It is therefore likely that K and Deltav/v are determined by the same localized excitations responsible for C , but the temperature dependence of the dielectric constant may have a different, though possibly related, origin. Furthermore, a consistent account for the measured C , K, ex and Deltav/v of unirradiated silica is given by the tunneling-state model with a single, energy-dependent density of states. Changes in these three properties due to irradiation can be explained by altering only the density of tunneling states incorporated in the model.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-29T14:45:40Z No. of bitstreams: 1 1979_Smith.pdf: 5449893 bytes, checksum: bd472bf664c9576eeb342ade4bf45015 (MD5)","Made available in DSpace on 2011-06-29T14:45:40Z (GMT). No. of bitstreams: 1 1979_Smith.pdf: 5449893 bytes, checksum: bd472bf664c9576eeb342ade4bf45015 (MD5) Previous issue date: 1979","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-29T14:45:40Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:16:39-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["The effect of neutron irradiation on the density of low-energy excitations in vitreous silica"]}]}],"canonical_facts":{"dc:contributor":["Anderson, A.C."],"dc:creator":["Smith, Terry Lee"],"dc:date":["2011-06-29T14:45:40Z","10000-01-01","1979"],"dc:description":["Systematic low-temperature measurements of the thermal conductivity, specific heat, dielectric constant, and temperature-dependent ultrasound velocity have been made on a single piece of vitreous silica. These measurements were repeated after fast neutron irradiation of the material. It was found that the irradiation produced changes of the same relative magnitude in the low-temperature excess specific heat C , the thermal conductivity K, ex and the anomalous temperature dependence of the ultrasound velocity Deltav/v. A corresponding change in the temperature dependent dielectric constant was not observed. It is therefore likely that K and Deltav/v are determined by the same localized excitations responsible for C , but the temperature dependence of the dielectric constant may have a different, though possibly related, origin. Furthermore, a consistent account for the measured C , K, ex and Deltav/v of unirradiated silica is given by the tunneling-state model with a single, energy-dependent density of states. Changes in these three properties due to irradiation can be explained by altering only the density of tunneling states incorporated in the model.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-29T14:45:40Z No. of bitstreams: 1 1979_Smith.pdf: 5449893 bytes, checksum: bd472bf664c9576eeb342ade4bf45015 (MD5)","Made available in DSpace on 2011-06-29T14:45:40Z (GMT). No. of bitstreams: 1 1979_Smith.pdf: 5449893 bytes, checksum: bd472bf664c9576eeb342ade4bf45015 (MD5) Previous issue date: 1979","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-29T14:45:40Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:16:39-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"],"dc:identifier":["397342","http://hdl.handle.net/2142/25562"],"dc:language":["en"],"dc:rights":["Copyright 1979 Terry Lee Smith"],"dc:subject":["Neutron irradiation","Low-energy excitations","Vitreous silica","Thermal conductivity","Specific heat","Dielectric constant","Ultrasound velocity"],"dc:title":["The effect of neutron irradiation on the density of low-energy excitations in vitreous silica"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:24Z"}