9 August 2016 Cryogenic near infrared spectropolarimeter for the Daniel K. Inouye Solar Telescope
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The Cryogenic Near Infrared Spectropolarimeter for the Daniel K Inouye Solar Telescope is designed to measure polarized light from 0.5 to 5 μm. It uses an almost all reflective design for high throughput and an R2 echelle grating to achieve the required resolution of up to R = 100,000. The optics cooled to cryogenic temperatures reduce the thermal background allowing for IR observations of the faint solar corona. Both the spectrograph and its context imager use H2RG detector arrays with a newly designed controller to allow synchronized exposures at frame rates up to 10 Hz. All hardware has been built and tested and the key components met their design goals. 1) The cryogenic system uses mechanical closed cycle coolers which introduce vibrations. Our design uses a two stage approach with a floating mounting disk and flexible cold links to reduce these. The vibration amplitudes on all critical stages were measured and are smaller than 1μm. 2) The grating stage of the spectrograph uses a double stack of harmonic drives and an optical encoder to provide sub-arcsecond resolution and a measured repeatability of better than 0.5 arcsec.
© (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Andre Fehlmann, Andre Fehlmann, Cynthia Giebink, Cynthia Giebink, Jeffrey R. Kuhn, Jeffrey R. Kuhn, Ernesto J. Messersmith, Ernesto J. Messersmith, Donald L. Mickey, Donald L. Mickey, Isabelle F. Scholl, Isabelle F. Scholl, Don James, Don James, Kirby Hnat, Kirby Hnat, Greg Schickling, Greg Schickling, Richard Schickling, Richard Schickling, "Cryogenic near infrared spectropolarimeter for the Daniel K. Inouye Solar Telescope", Proc. SPIE 9908, Ground-based and Airborne Instrumentation for Astronomy VI, 99084D (9 August 2016); doi: 10.1117/12.2232218; https://doi.org/10.1117/12.2232218

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