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TIME: A Millimeter-Wavelength Grating Spectrometer Array for [CII] / CO Intensity Mapping


Hunacek, Jonathon Robert (2020) TIME: A Millimeter-Wavelength Grating Spectrometer Array for [CII] / CO Intensity Mapping. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/hp2n-8495.


In this thesis I review the design, fabrication, and initial engineering deployment of the TIME (Tomographic Ionized-carbon Mapping Experiment) instrument. TIME seeks to make a first detection of the clustering amplitude of the power spectrum of redshifted [CII] emission from the Epoch of Reionization (z = 5-9). [CII], the 157.7 µm fine-structure line of singly ionized carbon, traces star formation on large scales, providing a new method for constraining the contribution of star formation to the Reionization process. [CII] intensity mapping complements traditional galaxy surveys by using spatially-broad beams to integrate signal from the many faint sources thought to be responsible for the bulk of the integrated emission from galaxies. TIME covers the 200-300 GHz atmospheric window, which also enables the study of lower-redshift CO emission (z = 0.5-2), a tracer of molecular gas in the period following the peak of cosmic star formation. The full TIME instrument consists of 32 single-polarization grating spectrometers with a resolution R ~ 100. Each spectrometer consists of an input feedhorn coupled to parallel plate waveguide with a curved diffraction grating, which focuses the diffracted light onto an output arc populated by 60 transition-edge sensor (TES) bolometers at 250 mK. The 1920 total detectors couple to the output of the parallel plate waveguide with a direct-absorbing micro-mesh and are organized into buttable arrays covering 4 spatial by either 12 (HF) or 8 (LF) spectral pixels. A partial TIME instrument was field tested in early 2019 on the ARO APA 12m dish at Kitt Peak. We intend to return to Kitt Peak in late 2020 to begin initial science observations.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Epoch of reionization; intensity mapping; ionized carbon; transition edge sensors; instrumentation
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Bock, James J.
Thesis Committee:
  • Zmuidzinas, Jonas (chair)
  • Golwala, Sunil
  • Hopkins, Philip F.
  • Bock, James J.
Defense Date:21 April 2020
Record Number:CaltechTHESIS:04272020-121646677
Persistent URL:
Related URLs:
URLURL TypeDescription 3, 4, 5, and 7 from Hunacek et al. 2018 have been reprinted here with permission from the publisher. ItemPyHK source code, as described in Appendix D
Hunacek, Jonathon Robert0000-0001-7066-226X
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13683
Deposited By: Jonathon Hunacek
Deposited On:02 Jun 2020 16:43
Last Modified:17 Jun 2020 20:14

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