The Simons Observatory (SO) will be a cosmic microwave background (CMB) survey experiment with three small-aperture telescopes and one large-aperture telescope, which will observe from the Atacama Desert in Chile. In total, SO will field over 60,000 transition-edge sensor (TES) bolometers in six spectral bands centered between 27 and 280 GHz in order to achieve the sensitivity necessary to measure or constrain numerous cosmological quantities, as outlined in The Simons Observatory Collaboration et al. (2019). The 6~m Large Aperture Telescope (LAT), which will target the smaller angular scales of the CMB, utilizes a cryogenic receiver (LATR) designed to house up to 13 individual optics tubes. Each optics tube is comprised of three silicon lenses, IR blocking filters, and three dual-polarization, dichroic TES detector wafers. The scientific objectives of the SO project require these optics tubes to achieve high-throughput optical performance while maintaining exquisite control of systematic effects. We describe the integration and testing program for the SO LATR optics tubes that will verify the design and assembly of the optics tubes before they are shipped to the SO site and installed in the LATR cryostat. The program includes a quick turn-around test cryostat that is used to cool single optics tubes and validate the cryogenic performance and detector readout assembly. We discuss the optical design specifications the optics tubes must meet to be deployed on sky and the suite of optical test equipment that is prepared to measure these requirements.
@article{arxiv.2102.02129,
title = {The Integration and Testing Program for the Simons Observatory Large Aperture Telescope Optics Tubes},
author = {Kathleen Harrington and Carlos Sierra and Grace Chesmore and Shreya Sutariya and Aamir M. Ali and Steve K. Choi and Nicholas F. Cothard and Simon Dicker and Nicholas Galitzki and Shuay-Pwu Patty Ho and Anna M. Kofman and Brian J. Koopman and Jack Lashner and Jeff McMahon and Michael D. Niemack and John Orlowski-Scherer and Joseph Seibert and Max Silva-Feaver and Eve M. Vavagiakis and Zhilei Xu and Ningfeng Zhu},
journal= {arXiv preprint arXiv:2102.02129},
year = {2021}
}