The Simons Observatory: modeling optical systematics in the Large Aperture Telescope

Area of Science:

• Cosmology
• Astrophysical instrumentation
• Optical engineering

Background:

• The Simons Observatory Large Aperture Telescope (LAT) requires rigorous optical design.
• Evaluating performance metrics and systematic effects is crucial for telescope construction.

Purpose of the Study:

• To present geometrical and physical optics simulation results for the Simons Observatory LAT.
• To evaluate the final design of reflectors and cold optics.
• To assess the impact of design choices on performance and systematic effects.

Main Methods:

• Nonsequential ray tracing for cold optics and internal absorbers.
• Ray tracing simulations of telescope structure to minimize detector loading and near-field effects.
• Physical optics simulations for far-field beam patterns across frequencies and field locations.

Main Results:

• Optimized designs for reflectors and cold optics.
• Identified telescope geometries minimizing detector loading and spurious near-field effects.
• Estimated monochromatic far-field beam patterns to gauge optical performance.
• Characterized beam sidelobes from panel gap diffraction.

Conclusions:

• Optical simulations are integral to the Simons Observatory LAT design process.
• The simulations provide critical data for constructing high-performance telescope components.
• The findings ensure the telescope meets its scientific objectives by mitigating optical imperfections.