1. The POLARBEAR Fourier transform spectrometer calibrator and spectroscopic characterization of the POLARBEAR instrument
- Author
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Matsuda, F, Lowry, L, Suzuki, A, Fáundez, M Aguilar, Arnold, K, Barron, D, Bianchini, F, Cheung, K, Chinone, Y, Elleflot, T, Fabbian, G, Goeckner-Wald, N, Hasegawa, M, Kaneko, D, Katayama, N, Keating, B, Lee, AT, Navaroli, M, Nishino, H, Paar, H, Puglisi, G, Richards, PL, Seibert, J, Siritanasak, P, Tajima, O, Takatori, S, Tsai, C, and Westbrook, B
- Subjects
Communications Engineering ,Engineering ,Physical Sciences ,astro-ph.IM ,Chemical Sciences ,Applied Physics ,Chemical sciences ,Physical sciences - Abstract
We describe the Fourier Transform Spectrometer (FTS) used for in-field testing of the POLARBEAR receiver, an experiment located in the Atacama Desert of Chile which measures the cosmic microwave background (CMB) polarization. The POLARBEAR-FTS (PB-FTS) is a Martin-Puplett interferometer designed to couple to the Huan Tran Telescope (HTT) on which the POLARBEAR receiver is installed. The PB-FTS measured the spectral response of the POLARBEAR receiver with signal-to-noise ratio >20 for ∼69% of the focal plane detectors due to three features: a high throughput of 15.1 sr cm2, optimized optical coupling to the POLARBEAR optics using a custom designed output parabolic mirror, and a continuously modulated output polarizer. The PB-FTS parabolic mirror is designed to mimic the shape of the 2.5 m-diameter HTT primary reflector, which allows for optimum optical coupling to the POLARBEAR receiver, reducing aberrations and systematics. One polarizing grid is placed at the output of the PB-FTS and modulated via continuous rotation. This modulation allows for decomposition of the signal into different harmonics that can be used to probe potentially pernicious sources of systematic error in a polarization-sensitive instrument. The high throughput and continuous output polarizer modulation features are unique compared to other FTS calibrators used in the CMB field. In-field characterization of the POLARBEAR receiver was accomplished using the PB-FTS in April 2014. We discuss the design, construction, and operation of the PB-FTS and present the spectral characterization of the POLARBEAR receiver. We introduce future applications for the PB-FTS in the next-generation CMB experiment, the Simons Array.
- Published
- 2019