{"paper":{"title":"A cryogenic rotation stage with a large clear aperture for the half-wave plates in the Spider instrument","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.CO"],"primary_cat":"astro-ph.IM","authors_text":"Alexandra S. Rahlin, Amy Trangsrud, Anne Gambrel, Anthony Turner, Aurelien Fraisse, Benjamin Elder, Benjamin Saliwanchik, Brendan Crill, Carlo Contaldi, Carl Reintsema, Carole Tucker, Carrie MacTavish, C. Barth Netterfield, Craig Lawrie, Daniel C. Riley, Donald Wiebe, Edward Young, Gene Hilton, H. Cynthia Chiang, Ivan Padilla, James Bock, Jamil Shariff, Jeffrey Filippini, Johanna Nagy, John Ruhl, Jon Gudmundsson, J. Richard Bond, Juan Soler, Kent Irwin, Krikor Megerian, Lorenzo Moncelsi, Mandana Amiri, Marcus Runyan, Mark Halpern, Matthew Hasselfield, Natalie Gandilo, Olivier Dore, Peter Ade, Peter Mason, Rebecca Tucker, Richard Bihary, Sean Bryan, Shyang Wen, Steven Benton, Thomas Montroy, Tracy Morford, Viktor Hristov, Warren Holmes, William Jones, Zigmund Kermish","submitted_at":"2015-10-06T22:16:52Z","abstract_excerpt":"We describe the cryogenic half-wave plate rotation mechanisms built for and used in Spider, a polarization-sensitive balloon-borne telescope array that observed the Cosmic Microwave Background at 95 GHz and 150 GHz during a stratospheric balloon flight from Antarctica in January 2015. The mechanisms operate at liquid helium temperature in flight. A three-point contact design keeps the mechanical bearings relatively small but allows for a large (305 mm) diameter clear aperture. A worm gear driven by a cryogenic stepper motor allows for precise positioning and prevents undesired rotation when th"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1510.01771","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}