Hafnium Films and Magnetic Shielding for TIME, A mm-Wavelength Spectrometer Array
Abstract
TIME is a mm-wavelength grating spectrometer array that will map fluctuations of the 157.7-μm emission line of singly ionized carbon ([CII]) during the epoch of reionization (redshift z ∼5–9). Sixty transition-edge sensor (TES) bolometers populate the output arc of each of the 32 spectrometers, for a total of 1920 detectors. Each bolometer consists of gold absorber on a ∼ 3 × 3 mm silicon nitride micro-mesh suspended near the corners by 1 × 1 × 500 μm silicon nitride legs targeting a photon-noise-dominated NEP ∼1×10^(-17)W/√Hz. Hafnium films are explored as a lower-T_c alternative to Ti (500 mK) for TIME TESs, allowing thicker support legs for improved yield. Hf T_c is shown to vary between 250 and 450 mK when varying the resident Ar pressure during deposition. Magnetic shielding designs and simulations are presented for the TIME first-stage SQUIDs. Total axial field suppression is predicted to be 5×10^7.
Additional Information
© 2018 Springer Science+Business Media, LLC, part of Springer Nature. Received: 30 October 2017; Accepted: 29 March 2018; First Online: 06 April 2018. JH is supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469. AC is supported by the National Science Foundation Astronomy and Astrophysics Postdoctoral Fellowship under Grant No. 1602677.Additional details
- Eprint ID
- 85871
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- CaltechAUTHORS:20180416-085137740
- NSF Graduate Research Fellowship
- DGE-1144469
- NSF Astronomy and Astrophysics Fellowship
- AST-1602677
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2018-04-16Created from EPrint's datestamp field
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2021-11-15Created from EPrint's last_modified field
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- Astronomy Department