Development of a cold chopper for TAO/MIMIZUKU

Mitsuhiko Honda; Takafumi Kamizuka; Ichiro Jikuya; Takashi Miyata; Kotaro Kato; Daichi Uchida; Shingo Kondo; Tsubasa Michifuji; Katsuhiko Yamada

doi:10.1117/12.2561926

13 December 2020 Development of a cold chopper for TAO/MIMIZUKU

Mitsuhiko Honda, Takafumi Kamizuka, Ichiro Jikuya, Takashi Miyata, Kotaro Kato, Daichi Uchida, Shingo Kondo, Tsubasa Michifuji, Katsuhiko Yamada

Author Affiliations +

Proceedings Volume 11451, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV; 114514Z (2020) https://doi.org/10.1117/12.2561926
Event: SPIE Astronomical Telescopes + Instrumentation, 2020, Online Only

Conference Poster

Abstract

An internal cold chopper is one of the key elements for the ground-based mid-infrared astronomical instruments of the next generation large telescopes such as TMT, GMT, and ELT. For ground-based mid-infrared observations, time variations of radiation from atmosphere, telescope, and instrument are often many times greater than the radiation from targets. Relatively fast (~5 Hz) beam switching technique (chopping) using the oscillating secondary mirror is often used for 8-m class telescopes to remove these background variations, but this is impractical for the 30-m class telescopes due to their much larger secondary mirror. Instead of it, internal chopping mirror is desired for the next generation groundbased mid-infrared astronomy. However, since the mid-IR instruments are usually cooled as low as ~30 K, such internal chopping mirror should also be cooled to that low temperature and low power dissipation of <1 W is required to maintain the low temperature environment, thus it is not so easy to have such cold chopper. As a testbed for that, we are developing an internal cold chopper for the mid-infrared instrument MIMIZUKU for the University of Tokyo Atacama Observatory (TAO) 6.5-m telescope. We use a voice-coil-like structure as actuators and capacitive gap sensors as position sensors. We construct a feedback control system for the rectangular command signal. We made a prototype cold chopper for TAO/MIMIZUKU and are currently evaluating this system. We present the current design of the cold chopper for MIMIZUKU and results of performance evaluation in the laboratory.

Citation Download Citation

Mitsuhiko Honda, Takafumi Kamizuka, Ichiro Jikuya, Takashi Miyata, Kotaro Kato, Daichi Uchida, Shingo Kondo, Tsubasa Michifuji, and Katsuhiko Yamada "Development of a cold chopper for TAO/MIMIZUKU", Proc. SPIE 11451, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV, 114514Z (13 December 2020); https://doi.org/10.1117/12.2561926

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available