We present geometrical and physical optics simulation results for the Simons Observatory Large Aperture Telescope. This work was developed as part of the general design process for the telescope; allowing us to evaluate the impact of various design choices on performance metrics and potential systematic effects. The primary goal of the simulations was to evaluate the final design of the reflectors and the cold optics which are now being built. We describe non-sequential ray tracing used to inform the design of the cold optics, including absorbers internal to each optics tube. We discuss ray tracing simulations of the telescope structure that allow us to determine geometries that minimize detector loading and mitigate spurious near-field effects that have not been resolved by the internal baffling. We also describe physical optics simulations, performed over a range of frequencies and field locations, that produce estimates of monochromatic far field beam patterns which in turn are used to gauge general optical performance. Finally, we describe simulations that shed light on beam sidelobes from panel gap diffraction.
@article{arxiv.2009.10138,
title = {The Simons Observatory: Modeling Optical Systematics in the Large Aperture Telescope},
author = {Jon E. Gudmundsson and Patricio A. Gallardo and Roberto Puddu and Simon R. Dicker and Alexandre E. Adler and Aamir M. Ali and Andrew Bazarko and Grace E. Chesmore and Gabriele Coppi and Nicholas F. Cothard and Nadia Dachlythra and Mark Devlin and Rolando Dünner and Giulio Fabbian and Nicholas Galitzki and Joseph E. Golec and Shuay-Pwu Patty Ho and Peter C. Hargrave and Anna M. Kofman and Adrian T. Lee and Michele Limon and Frederick T. Matsuda and Philip D. Mauskopf and Kavilan Moodley and Federico Nati and Michael D. Niemack and John Orlowski-Scherer and Lyman A. Page and Bruce Partridge and Giuseppe Puglisi and Christian L. Reichardt and Carlos E. Sierra and Sara M. Simon and Grant P. Teply and Carole Tucker and Edward J. Wollack and Zhilei Xu and Ningfeng Zhu},
journal= {arXiv preprint arXiv:2009.10138},
year = {2021}
}