Preflight characterization of the BLAST-TNG receiver and detector arrays

• Main Authors: Lourie, N., Ade, P., Angile, F., Ashton, P., Austermann, J., Devlin, M., Dober, B., Galitzki, N., Gao, J., Gordon, S., Groppi, C., Klein, J., Hilton, G., Hubmayr, J., Li, D., Lowe, I., Mani, H., Mauskopf, P., McKenney, C., Nati, F., Novak, G., Pascale, E., Pisano, G., Sinclair, A., Soler, J., Tucker, C., Ullom, J., Vissers, M., Williams, P.
• Format: Conference Object
• Language: unknown
• Published: 2018
• Subjects: McMurdo Station; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/21.11116/0000-0005-CC6E-B

The Next Generation Balloon-borne Large Aperture Submillimeter Telescope (BLAST-TNG) is a submillimeter mapping experiment planned for a 28 day long-duration balloon (LDB) flight from McMurdo Station, Antarctica during the 2018-2019 season. BLAST-TNG will detect submillimeter polarized interstellar dust emission, tracing magnetic fields in galactic molecular clouds. BLAST-TNG will be the first polarimeter with the sensitivity and resolution to probe the 0.1 parsec-scale features that are critical to understanding the origin of structures in the interstellar medium. BLAST-TNG features three detector arrays operating at wavelengths of 250, 350, and 500 m (1200, 857, and 600 GHz) comprised of 918, 469, and 272 dual-polarization pixels, respectively. Each pixel is made up of two crossed microwave kinetic inductance detectors (MKIDs). These arrays are cooled to 275 mK in a cryogenic receiver. Each MKID has a different resonant frequency, allowing hundreds of resonators to be read out on a single transmission line. This inherent ability to be frequency-domain multiplexed simplifies the cryogenic readout hardware, but requires careful optical testing to map out the physical location of each resonator on the focal plane. Receiver-level optical testing was carried out using both a cryogenic source mounted to a movable xy-stage with a shutter, and a beam-filling, heated blackbody source able to provide a 10-50 C temperature chop. The focal plane array noise properties, responsivity, polarization efficiency, instrumental polarization were measured. We present the preflight characterization of the BLAST-TNG cryogenic system and array-level optical testing of the MKID detector arrays in the flight receiver.