{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/106770"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/106770","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"Impact of x-ray dose on the response of CR-39 nuclear track detector to 1-5.5 MeV alphas and 0.5-9.1 MeV protons for spectroscopy at the OMEGA Laser Facility and the National Ignition Facility","abstract":"The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray fluences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to protons and alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 30 and 8keV Cu-K[alpha] and K[beta] x-rays. The CR-39 detectors were then exposed to 1-5.5 MeV alphas or 0.5- 9.1 MeV protons. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0±0.1 Gy causes a decrease of (19±2)% in the track diameter of a 5.5 MeV alpha, while a dose of 6.0±0.1 Gy results in a decrease of (29±1)% in the track diameter of a 3.0 MeV proton. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect, due to changes in track etch rate and dependent on incident particle energy, was characterized by an empirical formula.","abstract_html":"The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray fluences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to protons and alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 30 and 8keV Cu-K[alpha] and K[beta] x-rays. The CR-39 detectors were then exposed to 1-5.5 MeV alphas or 0.5- 9.1 MeV protons. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0±0.1 Gy causes a decrease of (19±2)% in the track diameter of a 5.5 MeV alpha, while a dose of 6.0±0.1 Gy results in a decrease of (29±1)% in the track diameter of a 3.0 MeV proton. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect, due to changes in track etch rate and dependent on incident particle energy, was characterized by an empirical formula.","abstract_has_math":false,"creators":["Rojas, Jimmy A. (Rojas Herrera)"],"institution":"Massachusetts Institute of Technology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Department of Nuclear Science and Engineering.","school":null,"contributors":[],"advisors":["Richard Petrasso."],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016","date_published":"2016","updated_at":"2026-07-22T22:22:23Z","subjects":["Nuclear Science and Engineering."],"languages":["eng"],"rights":["MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission."],"rights_urls":["http://dspace.mit.edu/handle/1721.1/7582"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1721.1/106770","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Richard Petrasso."]},{"key":"dc:contributor.department","label":"Department","values":["Massachusetts Institute of Technology. Department of Nuclear Science and Engineering."]},{"key":"dc:contributor.other","label":"Dc Contributor Other","values":["Massachusetts Institute of Technology. Department of Nuclear Science and Engineering."]},{"key":"dc:creator","label":"Author","values":["Rojas, Jimmy A. 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They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission."]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://dspace.mit.edu/handle/1721.1/7582"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1721.1/106770"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, June 2016.","Page 47 blank. Cataloged from PDF version of thesis.","Includes bibliographical references (pages 45-46)."]},{"key":"dc:description.abstract","label":"Abstract","values":["The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray fluences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to protons and alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 30 and 8keV Cu-K[alpha] and K[beta] x-rays. The CR-39 detectors were then exposed to 1-5.5 MeV alphas or 0.5- 9.1 MeV protons. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0±0.1 Gy causes a decrease of (19±2)% in the track diameter of a 5.5 MeV alpha, while a dose of 6.0±0.1 Gy results in a decrease of (29±1)% in the track diameter of a 3.0 MeV proton. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect, due to changes in track etch rate and dependent on incident particle energy, was characterized by an empirical formula."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["S.B."]},{"key":"dc:title","label":"Title","values":["Impact of x-ray dose on the response of CR-39 nuclear track detector to 1-5.5 MeV alphas and 0.5-9.1 MeV protons for spectroscopy at the OMEGA Laser Facility and the National Ignition Facility"]}]}],"canonical_facts":{"dc:contributor.advisor":["Richard Petrasso."],"dc:contributor.department":["Massachusetts Institute of Technology. Department of Nuclear Science and Engineering."],"dc:contributor.other":["Massachusetts Institute of Technology. Department of Nuclear Science and Engineering."],"dc:creator":["Rojas, Jimmy A. (Rojas Herrera)"],"dc:date.accessioned":["2017-01-30T19:17:33Z"],"dc:date.available":["2017-01-30T19:17:33Z"],"dc:date.issued":["2016"],"dc:description":["Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, June 2016.","Page 47 blank. Cataloged from PDF version of thesis.","Includes bibliographical references (pages 45-46)."],"dc:description.abstract":["The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray fluences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to protons and alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 30 and 8keV Cu-K[alpha] and K[beta] x-rays. The CR-39 detectors were then exposed to 1-5.5 MeV alphas or 0.5- 9.1 MeV protons. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0±0.1 Gy causes a decrease of (19±2)% in the track diameter of a 5.5 MeV alpha, while a dose of 6.0±0.1 Gy results in a decrease of (29±1)% in the track diameter of a 3.0 MeV proton. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect, due to changes in track etch rate and dependent on incident particle energy, was characterized by an empirical formula."],"dc:description.degree":["S.B."],"dc:identifier.uri":["http://hdl.handle.net/1721.1/106770"],"dc:language.iso":["eng"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission."],"dc:rights.uri":["http://dspace.mit.edu/handle/1721.1/7582"],"dc:subject":["Nuclear Science and Engineering."],"dc:title":["Impact of x-ray dose on the response of CR-39 nuclear track detector to 1-5.5 MeV alphas and 0.5-9.1 MeV protons for spectroscopy at the OMEGA Laser Facility and the National Ignition Facility"],"dc:type":["Thesis"]},"updated_at":"2026-07-22T22:22:23Z"}