280 GHz Focal Plane Unit Design and Characterization for the Spider-2 Suborbital Polarimeter

• Published in: Journal of Low Temperature Physics
• Main Authors: Bergman, A. S., Bock, J. J., Doré, O., Hristov, V. V., Mason, P. V., Moncelsi, L., Morford, T. A., Trangsrud, A., Tucker, R. S.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer 2018
• Subjects: Detector packaging · Magnetic shielding · Transition-edge sensors · Scientific ballooning · Cosmic microwave background; Antarctic; The Antarctic; Antarc*
• Online Access: https://doi.org/10.1007/s10909-018-2065-2

We describe the construction and characterization of the 280 GHz bolometric focal plane units (FPUs) to be deployed on the second flight of the balloon-borne Spider instrument. These FPUs are vital to Spider's primary science goal of detecting or placing an upper limit on the amplitude of the primordial gravitational wave signature in the cosmic microwave background (CMB) by constraining the B-mode contamination in the CMB from Galactic dust emission. Each 280 GHz focal plane contains a 16×16 grid of corrugated silicon feedhorns coupled to an array of aluminum–manganese transition-edge sensor (TES) bolometers fabricated on 150 mm diameter substrates. In total, the three 280 GHz FPUs contain 1530 polarization-sensitive bolometers (765 spatial pixels) optimized for the low loading environment in flight and read out by time-division SQUID multiplexing. In this paper, we describe the mechanical, thermal, and magnetic shielding architecture of the focal planes and present cryogenic measurements which characterize yield and the uniformity of several bolometer parameters. The assembled FPUs have high yields, with one array as high as 95% including defects from wiring and readout. We demonstrate high uniformity in device parameters, finding the median saturation power for each TES array to be ∼ 3 pW at 300 mK with a less than 6% variation across each array at 1 © Springer Science+Business Media, LLC, part of Springer Nature 2018. Received: 11 November 2017 / Accepted: 29 August 2018 / Published online: 12 September 2018. Spider is supported in the USA by the National Aeronautics and Space Administration under Grant Nos. NNX17AC55G and NNX12AE95G issued through the Science Mission Directorate and by the National Science Foundation through PLR-1043515. Additional support is provided by the Department of Energy Grant DE-SC007859. Corresponding author is supported by a National Science Foundation Graduate Research Fellowship. Logistical support for the Antarctic deployment and operations was provided by the NSF ...