University of Illinois Urbana-Champaign

The terahertz intensity mapper: development of the cryogenic receiver

Fu, Jianyang

Permalink

https://hdl.handle.net/2142/132548

Description

Title
The terahertz intensity mapper: development of the cryogenic receiver
Author(s)
Fu, Jianyang
Issue Date
2025-12-02
Director of Research (if dissertation) or Advisor (if thesis)
  • Vieira, Joaquin D
  • Filippini, Jeffrey P
Doctoral Committee Chair(s)
Vieira, Joaquin D
Committee Member(s)
  • Looney, Leslie W
  • Ricker, Paul M
Department of Study
Astronomy
Discipline
Astronomy
Degree Granting Institution
University of Illinois Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • Far-infrared
  • Terahertz
  • Line Intensity Mapping
  • Kinetic Inductance Detector
  • Scientific Ballooning
  • 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.
Graduation Semester
2025-12
Type of Resource
Thesis
Handle URL
https://hdl.handle.net/2142/132548
Copyright and License Information
Copyright 2025 Jianyang Fu

Owning Collections

Graduate Dissertations and Theses at Illinois PRIMARY
Graduate Theses and Dissertations at Illinois