Abstract
The Simons Observatory (SO) is a cosmic microwave background instrumentation suite being deployed in the Atacama Desert in northern Chile. The telescopes within SO use three types of dichroic transition-edge sensor (TES) detector arrays, with the 90 and 150 GHz Mid-Frequency (MF) arrays containing 65% of the approximately 68,000 detectors in the first phase of SO. All of the 26 required MF detector arrays have now been fabricated, packaged into detector modules, and tested in laboratory cryostats. Across all modules, we find an average operable detector yield of 84% and median saturation powers of (2.8, 8.0) pW with interquartile ranges of (1, 2) pW at (90, 150) GHz, respectively, falling within their targeted ranges. We measure TES normal resistances and superconducting transition temperatures on each detector wafer to be uniform within 3%, with overall central values of 7.5 m\(\Omega\) and 165 mK, respectively. Results on time constants, optical efficiency, and noise performance are also presented and are consistent with achieving instrument sensitivity forecasts.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Notes
In this work, we define saturation power as the electrical bias power required to bias an optically-dark TES to 50% \(R_N\) at the intended operating bath temperature of 100 mK. We denote this quantity as \(P_{b50}\).
Initial module testing often reveals one or more shorted multiplexer chips, which, if no compatible replacement chips are available, are replaced with passive through chips with no resonators. If these missing multiplexer chips are omitted from the expected total, the resonator yield increases to 99%.
The SO MF baseline model assumed a larger pixel size, and therefore fewer detectors per wafer, than the as-built version. The realized percentage detector yield (84%) also exceeds that used in the model (70%). The larger detector count offsets the increase in NEP.
References
The Simons Observatory Collaboration et al., The Simons Observatory: science goals and forecasts. J. Cosmol. Astropart. Phys. 2019, 056 (2019). https://doi.org/10.1088/1475-7516/2019/02/056
S. M. Duff et al., The Simons observatory: production-level fabrication of the mid- and ultra-high-frequency wafers. J. Low Temp. Phys. This special issue LTD20 (2023)
B. Dober et al., A Microwave SQUID Multiplexer Optimized for Bolometric Applications (2020). https://doi.org/10.1063/5.0033416. arXiv:2010.07998
D. Jones et al., Qualification of microwave SQUID multiplexer chips for simons observatory. J. Low Temp. Phys. This special issue LTD20 (2023)
E. Healy et al., Assembly development for the Simons Observatory focal plane readout module. Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX 11453, 224–235 (2020). https://doi.org/10.1117/12.2561743
H. McCarrick et al., The Simons observatory microwave SQUID multiplexing detector module design. ApJ 922, 38 (2021). https://doi.org/10.3847/1538-4357/ac2232
C. Yu et al., SLAC Microresonator RF (SMuRF) electronics: a tone-tracking readout system for superconducting microwave resonator arrays. Rev. Sci. Instrum. 94, 014712 (2023). https://doi.org/10.1063/5.0125084. arXiv:2208.10523 [astro-ph, physics:physics]
H. McCarrick et al., The 90 and 150 GHz universal focal-plane modules for the Simons Observatory (2021). https://doi.org/10.48550/arXiv.2112.01458. arXiv:2112.01458 [astro-ph]
Y. Wang et al., Simons observatory focal-plane module: in-lab testing and characterization program. J. Low Temp. Phys. 209, 944–952 (2022). https://doi.org/10.1007/s10909-022-02870-1
M. D. Niemack, Towards dark energy: Design, development, and preliminary data from ACT. Ph.D. Thesis, Princeton University (2008)
S.M. Simon et al., In situ time constant and optical efficiency measurements of TRUCE pixels in the Atacama B-mode search. J. Low Temp. Phys. 176, 712–718 (2014). https://doi.org/10.1007/s10909-013-0999-y
Acknowledgements
This work was supported in part by the Simons Foundation (Award #457687, B.K.).
Author information
Authors and Affiliations
Contributions
Manuscript and figures prepared by DD. Data collected by DD, YW, KZ, RFS, EH, and SM, with final synthesis by DD. Design, fabrication, and screening of device components by MJL, TJL, SMD, JH, JCG, BRJ, DJ, BK, LTL, and YS. Module design and assembly process developed by EH. Project directed by STS and JH. All authors reviewed the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Dutcher, D., Duff, S.M., Groh, J.C. et al. The Simons Observatory: Large-Scale Characterization of 90/150 GHz TES Detector Modules. J Low Temp Phys 214, 247–255 (2024). https://doi.org/10.1007/s10909-023-03045-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10909-023-03045-2