BoloCalc: A sensitivity calculator for the design of Simons Observatory

Charles A. Hill*, Sarah Marie M. Bruno, Sara M. Simon, Aamir Ali, Kam S. Arnold, Peter C. Ashton, Darcy Barron, Sean Bryan, Yuji Chinone, Gabriele Coppi, Kevin T. Crowley, Ari Cukierman, Simon Dicker, Jo Dunkley, Giulio Fabbian, Nicholas Galitzki, Patricio A. Gallardo, Jon E. Gudmundsson, Johannes Hubmayr, Brian KeatingAkito Kusaka, Adrian T. Lee, Frederick Matsuda, Philip D. Mauskopf, Jeffrey McMahon, Michael D. Niemack, Giuseppe Puglisi, Mayuri Sathyanarayana Rao, Maria Salatino, Carlos Sierra, Suzanne Staggs, Aritoki Suzuki, Grant Teply, Joel N. Ullom, Benjamin Westbrook, Zhilei Xu, Ningfeng Zhu

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

15 Citations (Scopus)


The Simons Observatory (SO) is an upcoming experiment that will study temperature and polarization fluctuations in the cosmic microwave background (CMB) from the Atacama Desert in Chile. SO will field both a large aperture telescope (LAT) and an array of small aperture telescopes (SATs) that will observe in six bands with center frequencies spanning from 27 to 270 GHz. Key considerations during the SO design phase are vast, including the number of cameras per telescope, focal plane magnification and pixel density, in-band optical power and camera throughput, detector parameter tolerances, and scan strategy optimization. To inform the SO design in a rapid, organized, and traceable manner, we have created a Python-based sensitivity calculator with several state-of-the-art features, including detector-to-detector optical white-noise correlations, a handling of simulated and measured bandpasses, and propagation of low-level parameter uncertainties to uncertainty in on-sky noise performance. We discuss the mathematics of the sensitivity calculation, the calculator's object-oriented structure and key features, how it has informed the design of SO, and how it can enhance instrument design in the broader CMB community, particularly for CMB-S4.

Original languageEnglish
Title of host publicationMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX
EditorsJonas Zmuidzinas, Jian-Rong Gao
ISBN (Print)9781510619692
Publication statusPublished - 2018
EventMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX 2018 - Austin, United States
Duration: 12 Jun 201815 Jun 2018

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX 2018
Country/TerritoryUnited States

Bibliographical note

Funding Information:
This work was supported in part by a grant from the Simons Foundation (Award #457687, B.K.). We thank Scott Paine and Denis Barkats (Harvard University) for providing the atmospheric profiles for the Atacama and South Pole sites that are input into the AM simulations.

Publisher Copyright:
© 2018 SPIE.

Other keywords

  • CMB
  • Cosmic microwave background
  • mapping speed
  • noise
  • noise-equivalent temperature
  • sensitivity
  • Simons Observatory


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