Mr. Ryan P. Keenan Profile

Ryan P. Keenan

at Univ of Arizona

SPIE Involvement:

Author

Publications (4)

Proceedings Article | 31 August 2022 Poster + Paper

Design and testing of kinetic inductance detector package for the terahertz intensity mapper

L.-J. Liu, R. Janssen, C. Bradford, S. Hailey-Dunsheath, J. Filippini, J. Aguirre, J. Bracks, A. Corso, J. Fu, C. Groppi, J. Hoh, R. Keenan, I. Lowe, D. Marrone, P. Mauskopf, R. Nie, J. Redford, I. Trumper, J. Vieira

Proceedings Volume 12190, 121902F (2022) https://doi.org/10.1117/12.2629675

KEYWORDS: Galaxy evolution, Astronomy, Far infrared, Terahertz spectroscopy, Magnetism, Sensors, Aluminum, Semiconducting wafers, Stars, Magnetic sensors, Inductance, Prototyping, Galactic astronomy, Resonators

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The Terahertz Intensity Mapper (TIM) is designed to probe the star formation history in dust-obscured star-forming galaxies around the peak of cosmic star formation. This will be done via measurements of the redshifted 157.7 µm line of singly ionized carbon ([CII]). TIM employs two R~250 long-slit grating spectrometers covering 240 to 420 µm. Each is equipped with a focal plane unit containing four wafer-sized subarrays of horn-coupled aluminum kinetic inductance detectors (KIDs). We present the design and performance of a prototype focal plane assembly for one of TIM’s KID-based subarrays. The overall detector package must satisfy thermal and mechanical requirements, while maintaining high optical efficiency and a suitable electromagnetic environment for the KIDs. In particular, our design manages to strictly maintain a 50 µm air gap between the array and the horn block. The prototype detector housing in combination with the first flight-like quadrant were tested at 250 mK. A frequency scan using a vector network analyzer shows 823 resonance features, which represents ⪆90% yield, indicating a good performance of our TIM detector wafer and the whole focal plane unit. Initial measurements also showed that many resonances were affected by collisions and/or very shallow transmission dips as a result of a degraded internal quality factor. This is attributed to the presence of an external magnetic field during cooldown. We report on a study of magnetic field dependence of the quality factor of our quadrant array. We implemented a Helmholtz coil to vary the magnetic field at the detectors by (partially) nulling earth’s. Our investigation shows that the earth magnetic field can significantly affect our KIDs’ performance by degrading the quality factor by a factor of two to five, well below those expected from the operational temperature or optical loading. We find that we can sufficiently recover our detectors’ quality factor by tuning the current in the coils to generate a field that matches earth’s magnetic field in magnitude to within a few µT. We emphasize that it is impractical to fly a Helmholtz coil on TIM and dynamically “null” earth’s. Therefore, it is necessary to employ a properly designed magnetic shield enclosing the TIM focal plane unit. Based on the results presented in this paper, we set a shielding requirement of |B| ⪅3 µT.

Proceedings Article | 31 August 2022 Presentation + Paper

The terahertz intensity mapper: a balloon-borne imaging spectrometer for galaxy evolution

Daniel Marrone, James Aguirre, Justin Bracks, Charles Bradford, Brockton Brendal, Bruce Bumble, Anthony Corso, Mark Devlin, Nick Emerson, Jeffrey Filippini, Jianyang Fu, Victor Gasho, Christopher Groppi, Steve Hailey-Dunsheath, Jonathan Hoh, Matthew Hollister, Reinier M. Janssen, Dylan Joralmon, Ryan Keenan, Lun-Jun Liu, Ian Lowe, Philip Mauskopf, Evan Mayer, Rong Nie, Vesal Razavimaleki, Joseph Redford, Talia Saeid, Isaac Trumper, Joaquin Vieira

Proceedings Volume 12190, 1219008 (2022) https://doi.org/10.1117/12.2630644

KEYWORDS: Telescopes, Spectroscopy, Mirrors, Sensors, Cryogenics

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Proceedings Article | 26 August 2022 Presentation

Kinetic inductance detectors for the Terahertz Intensity Mapper balloon mission: optical sensitivity and performance of kilopixel arrays.

Reinier M. J. Janssen, Rong Nie, Bruce Bumble, Lun-Jun Liu, Joseph Redford, Jeffrey Filippini, Charles Bradford, Steve Hailey-Dunsheath, James Aguirre, Justin Bracks, Anthony Corso, Jianyang Fu, Christopher Groppi, Jonathan Hoh, Ryan Keenan, Ian Lowe, Daniel Marrone, Philip Mauskopf, Isaac Trumper, Joaquin Vieira

Proceedings Volume PC12190, PC121900Q (2022) https://doi.org/10.1117/12.2630516

KEYWORDS: Sensors, Inductance, Spectrometers, Photodetectors, Staring arrays, Spectral resolution, Quasiparticles, Optical testing, Capacitors

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Proceedings Article | 13 December 2020 Presentation

A status update on TIME: a mm-wavelength spectrometer designed to probe the Epoch of Reionization

Abigail Crites, Jamie Bock, Matt Bradford, Victoria Butler, Tzu-Ching Chang, Yun-Ting Cheng, Asantha Cooray, Nick Emerson, Clifford Frez, Jon Hunacek, Chao-Te Li, Ryan Keenan, Paolo Madonia, Lorenzo Moncelsi, Dan Marrone, Thomas Prouve, Guochao Sun, Isaac Trumper, Anthony Turner, Alexis Weber, Ta-Shun Wei, Mike Zemcov, Tess Case-Cortes

Proceedings Volume 11453, 114530G (2020) https://doi.org/10.1117/12.2561865

KEYWORDS: Spectroscopy, Spectrometer engineering, Time metrology, Sensors, Bolometers, Carbon monoxide, Stars, Galactic astronomy, Prototyping, Antennas

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