{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/132548"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/132548","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The terahertz intensity mapper: development of the cryogenic receiver","abstract":"Understanding galaxy evolution over cosmic time remains one of the most profound questions in modern astrophysics. Approximately half of cosmic star formation is obscured by dust and traced through far-infrared emission, but Earth's atmosphere blocks these wavelengths, making ground-based surveys extremely challenging. The Terahertz Intensity Mapper (\\TIM), a balloon-borne spectroscopic telescope operating in the stratosphere, overcomes these limitations and enables the mapping of galaxies following the peak epoch of cosmic star formation. \\TIM will pioneer line intensity mapping (LIM) at far-infrared wavelengths (240--420~\\si{\\micro\\meter}), employing two grating spectrometers coupled to over 7,000 superconducting kinetic inductance detectors to trace star formation through the [CII] 158~\\si{\\micro\\meter} emission line. This thesis presents my contributions to \\TIM cryogenic receiver across the full instrument development cycle: from initial conceptual design and thermal modeling through integration, commissioning, and characterization. I discuss the thermal architecture and the development of the 270~L liquid helium cryostat, the integration of the receiver subsystems including the sub-kelvin refrigerator, the focal plane unit and the cold optics, and the commissioning process that validated our models and prepared the instrument for deployment. This work addresses the technical challenges of building a stratospheric far-infrared spectrometer and has prepared \\TIM for its science flight in late 2026.","abstract_html":"Understanding galaxy evolution over cosmic time remains one of the most profound questions in modern astrophysics. Approximately half of cosmic star formation is obscured by dust and traced through far-infrared emission, but Earth's atmosphere blocks these wavelengths, making ground-based surveys extremely challenging. The Terahertz Intensity Mapper (\\TIM), a balloon-borne spectroscopic telescope operating in the stratosphere, overcomes these limitations and enables the mapping of galaxies following the peak epoch of cosmic star formation. \\TIM will pioneer line intensity mapping (LIM) at far-infrared wavelengths (240--420~\\si{\\micro\\meter}), employing two grating spectrometers coupled to over 7,000 superconducting kinetic inductance detectors to trace star formation through the [CII] 158~\\si{\\micro\\meter} emission line. This thesis presents my contributions to \\TIM cryogenic receiver across the full instrument development cycle: from initial conceptual design and thermal modeling through integration, commissioning, and characterization. I discuss the thermal architecture and the development of the 270~L liquid helium cryostat, the integration of the receiver subsystems including the sub-kelvin refrigerator, the focal plane unit and the cold optics, and the commissioning process that validated our models and prepared the instrument for deployment. This work addresses the technical challenges of building a stratospheric far-infrared spectrometer and has prepared \\TIM for its science flight in late 2026.","abstract_has_math":false,"creators":["Fu, Jianyang"],"institution":"University of Illinois Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Astronomy","degree_department":null,"school":null,"contributors":["Vieira, Joaquin D","Filippini, Jeffrey P","Looney, Leslie W","Ricker, Paul M"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-12","date_published":"2025-12","updated_at":"2026-07-22T22:25:07Z","subjects":["Far-infrared","Terahertz","Line Intensity Mapping","Kinetic Inductance Detector","Scientific Ballooning","Cryogenic","Receiver"],"languages":["en"],"rights":["Copyright 2025 Jianyang Fu"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/132548","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Vieira, Joaquin D","Filippini, Jeffrey P","Looney, Leslie W","Ricker, Paul M"]},{"key":"dc:creator","label":"Author","values":["Fu, Jianyang"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-12","2025-12-02"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Astronomy"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Far-infrared","Terahertz","Line Intensity Mapping","Kinetic Inductance Detector","Scientific Ballooning","Cryogenic","Receiver"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2025 Jianyang Fu"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/132548"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Understanding galaxy evolution over cosmic time remains one of the most profound questions in modern astrophysics. Approximately half of cosmic star formation is obscured by dust and traced through far-infrared emission, but Earth's atmosphere blocks these wavelengths, making ground-based surveys extremely challenging. The Terahertz Intensity Mapper (\\TIM), a balloon-borne spectroscopic telescope operating in the stratosphere, overcomes these limitations and enables the mapping of galaxies following the peak epoch of cosmic star formation. \\TIM will pioneer line intensity mapping (LIM) at far-infrared wavelengths (240--420~\\si{\\micro\\meter}), employing two grating spectrometers coupled to over 7,000 superconducting kinetic inductance detectors to trace star formation through the [CII] 158~\\si{\\micro\\meter} emission line. This thesis presents my contributions to \\TIM cryogenic receiver across the full instrument development cycle: from initial conceptual design and thermal modeling through integration, commissioning, and characterization. I discuss the thermal architecture and the development of the 270~L liquid helium cryostat, the integration of the receiver subsystems including the sub-kelvin refrigerator, the focal plane unit and the cold optics, and the commissioning process that validated our models and prepared the instrument for deployment. This work addresses the technical challenges of building a stratospheric far-infrared spectrometer and has prepared \\TIM for its science flight in late 2026.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2026-02-19 without embargo terms","The student, Jianyang Fu, accepted the attached license on 2025-12-02 at 02:08.","The student, Jianyang Fu, submitted this Dissertation for approval on 2025-12-02 at 02:13.","This Dissertation was approved for publication on 2025-12-02 at 08:20.","DSpace SAF Submission Ingestion Package generated from Vireo submission #22988 on 2026-02-19 at 18:25:46"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["The terahertz intensity mapper: development of the cryogenic receiver"]}]}],"canonical_facts":{"dc:contributor":["Vieira, Joaquin D","Filippini, Jeffrey P","Looney, Leslie W","Ricker, Paul M"],"dc:creator":["Fu, Jianyang"],"dc:date":["2025-12","2025-12-02"],"dc:description":["Understanding galaxy evolution over cosmic time remains one of the most profound questions in modern astrophysics. Approximately half of cosmic star formation is obscured by dust and traced through far-infrared emission, but Earth's atmosphere blocks these wavelengths, making ground-based surveys extremely challenging. The Terahertz Intensity Mapper (\\TIM), a balloon-borne spectroscopic telescope operating in the stratosphere, overcomes these limitations and enables the mapping of galaxies following the peak epoch of cosmic star formation. \\TIM will pioneer line intensity mapping (LIM) at far-infrared wavelengths (240--420~\\si{\\micro\\meter}), employing two grating spectrometers coupled to over 7,000 superconducting kinetic inductance detectors to trace star formation through the [CII] 158~\\si{\\micro\\meter} emission line. This thesis presents my contributions to \\TIM cryogenic receiver across the full instrument development cycle: from initial conceptual design and thermal modeling through integration, commissioning, and characterization. I discuss the thermal architecture and the development of the 270~L liquid helium cryostat, the integration of the receiver subsystems including the sub-kelvin refrigerator, the focal plane unit and the cold optics, and the commissioning process that validated our models and prepared the instrument for deployment. This work addresses the technical challenges of building a stratospheric far-infrared spectrometer and has prepared \\TIM for its science flight in late 2026.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2026-02-19 without embargo terms","The student, Jianyang Fu, accepted the attached license on 2025-12-02 at 02:08.","The student, Jianyang Fu, submitted this Dissertation for approval on 2025-12-02 at 02:13.","This Dissertation was approved for publication on 2025-12-02 at 08:20.","DSpace SAF Submission Ingestion Package generated from Vireo submission #22988 on 2026-02-19 at 18:25:46"],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/132548"],"dc:language":["en"],"dc:rights":["Copyright 2025 Jianyang Fu"],"dc:subject":["Far-infrared","Terahertz","Line Intensity Mapping","Kinetic Inductance Detector","Scientific Ballooning","Cryogenic","Receiver"],"dc:title":["The terahertz intensity mapper: development of the cryogenic receiver"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Astronomy"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:07Z"}