Browsing by Author "Sutariya, Shreya"

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    Simons Observatory: characterizing the Large Aperture Telescope Receiver with radio holography
    (2022) Chesmore, Grace E.; Harrington, Kathleen; Sierra, Carlos E.; Gallardo, Patricio A.; Sutariya, Shreya; Alford, Tommy; Adler, Alexandre E.; Bhandarkar, Tanay; Coppi, Gabriele; Dachlythra, Nadia; Golec, Joseph; Gudmundsson, Jon; Haridas, Saianeesh K.; Johnson, Bradley R.; Kofman, Anna M.; Iuliano, Jeffrey; Mcmahon, Jeff; Niemack, Michael D.; Orlowski-Scherer, John; Sarmiento, Karen Perez; Puddu, Roberto; Silva-Feaver, Max; Simon, Sara M.; Robe, Julia; Wollack, Edward J.; Xu, Zhilei
    We present near-field radio holography measurements of the Simons Observatory Large Aperture Telescope Receiver optics. These measurements demonstrate that radio holography of complex millimeter-wave optical systems comprising cryogenic lenses, filters, and feed horns can provide detailed characterization of wave propagation before deployment. We used the measured amplitude and phase, at 4 K, of the receiver near-field beam pattern to predict two key performance parameters: 1) the amount of scattered light that will spill past the telescope to 300 K and 2) the beam pattern expected from the receiver when fielded on the telescope. These cryogenic measurements informed the removal of a filter, which led to improved optical efficiency and reduced sidelobes at the exit of the receiver. Holography measurements of this system suggest that the spilled power past the telescope mirrors will be less than 1%, and the main beam with its near sidelobes are consistent with the nominal telescope design. This is the first time such parameters have been confirmed in the lab prior to deployment of a new receiver. This approach is broadly applicable to millimeter and submillimeter instruments. (c) 2022 Optica Publishing Group
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    The Simons Observatory Large Aperture Telescope Receiver
    (2021) Zhu, Ningfeng; Bhandarkar, Tanay; Coppi, Gabriele; Kofman, Anna M.; Orlowski-Scherer, John L.; Xu, Zhilei; Adachi, Shunsuke; Ade, Peter; Aiola, Simone; Austermann, Jason; Bazarko, Andrew O.; Beall, James A.; Bhimani, Sanah; Bond, J. Richard; Chesmore, Grace E.; Choi, Steve K.; Connors, Jake; Cothard, Nicholas F.; Devlin, Mark; Dicker, Simon; Dober, Bradley; Duell, Cody J.; Duff, Shannon M.; Dunner, Rolando; Fabbian, Giulio; Galitzki, Nicholas; Gallardo, Patricio A.; Golec, Joseph E.; Haridas, Saianeesh K.; Harrington, Kathleen; Healy, Erin; Ho, Shuay-Pwu Patty; Huber, Zachary B.; Hubmayr, Johannes; Iuliano, Jeffrey; Johnson, Bradley R.; Keating, Brian; Kiuchi, Kenji; Koopman, Brian J.; Lashner, Jack; Lee, Adrian T.; Li, Yaqiong; Limon, Michele; Link, Michael; Lucas, Tammy J.; McCarrick, Heather; Moore, Jenna; Nati, Federico; Newburgh, Laura B.; Niemack, Michael D.; Pierpaoli, Elena; Randall, Michael J.; Sarmiento, Karen Perez; Saunders, Lauren J.; Seibert, Joseph; Sierra, Carlos; Sonka, Rita; Spisak, Jacob; Sutariya, Shreya; Tajima, Osamu; Teply, Grant P.; Thornton, Robert J.; Tsan, Tran; Tucker, Carole; Ullom, Joel; Vavagiakis, Eve M.; Vissers, Michael R.; Walker, Samantha; Westbrook, Benjamin; Wollack, Edward J.; Zannoni, Mario
    The Simons Observatory is a ground-based cosmic microwave background experiment that consists of three 0.4 m small-aperture telescopes and one 6 m Large Aperture Telescope, located at an elevation of 5300 m on Cerro Toco in Chile. The Simons Observatory Large Aperture Telescope Receiver (LATR) is the cryogenic camera that will be coupled to the Large Aperture Telescope. The resulting instrument will produce arcminute-resolution millimeter-wave maps of half the sky with unprecedented precision. The LATR is the largest cryogenic millimeter-wave camera built to date, with a diameter of 2.4 m and a length of 2.6 m. The coldest stage of the camera is cooled to 100 mK, the operating temperature of the bolometric detectors with bands centered around 27, 39, 93, 145, 225, and 280 GHz. Ultimately, the LATR will accommodate 13 40 cm diameter optics tubes, each with three detector wafers and a total of 62,000 detectors. The LATR design must simultaneously maintain the optical alignment of the system, control stray light, provide cryogenic isolation, limit thermal gradients, and minimize the time to cool the system from room temperature to 100 mK. The interplay between these competing factors poses unique challenges. We discuss the trade studies involved with the design, the final optimization, the construction, and ultimate performance of the system.