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Performance evaluation of MKDs on a high-speed rotating system for CMB telescope: GroundBIRD (Conference Presentation)
Author(s): Satoru Mima; Jihoon Choi; Ricardo Tanausú Génova-Santos; Makoto Hattori; Masashi Hazumi; Hikaru Ishitsuka; Fumiyasu Kanno; Kenichi Karatsu; Kenji Kiuchi; Junta Komine; Ryo Koyano; Hiroki Kutsuma; Kyungmin Lee; Makoto Minowa; Makoto Nagai; Takeo Nagasaki; Masato Naruse; Shugo Oguri; Chiko Otani; Rafael Rebolo; José Alberto Rubiño-Martín; Yutaro Sekimoto; Munehisa Semoto; Junya Suzuki; Tohru Taino; Osamu Tajima; Nozomu Tomita; Tomohisa Uchida; Eunil Won; Mitsuhiro Yoshida
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Paper Abstract

The cosmic microwave background (CMB) radiation is an afterglow of the Big Bang. It contains the crucial keys to understand the beginning of the universe. In particular, the odd-parity patterns of CMB polarization, B-modes, at more than degree-scale, are the best probe to detect primordial gravitational waves at the cosmic inflation. The GroundBIRD experiment aims to detect this large angular scale patterns from the ground. The experiment employs novel techniques; a high-speed rotational scanning system (20 revolution-per-minutes) with cold optics below 4K, and microwave kinetic inductance detectors (MKIDs) as the focal plane detectors. The fast scanning modulation is a crucial characteristic in our observation strategy to mitigate effects of the atmospheric fluctuation. The telescope rotates and scans the sky along the azimuth at the elevation angle of 60 degrees at Teide observatory in the Canary Islands. It allows us to measure CMB polarization patterns at a wide multipole range, 6 < \ell < 300, i.e. aiming to catch the reionization bump. We have developed a telescope mount with 3-axis rotation mechanism (azimuth, elevation, and boresight). We are evaluating the vibration at the focal plane position with rotating the telescope mount. The focal plane consists of seven hexagonal corrugated horn coupled MKIDs array: six hexagon units are for 145 GHz band (55 pixels/unit), and one unit is for 220 GHz band (112 pixels). Each pixel consists of a corrugated horn, a planner OMT, millimeter wave circuits for transmission of dual-polarization signals with the suppression of crosstalk modes, and two MKIDs for each polarization. Magnetic shields are also mounted so as to suppress the external magnetic fields. Trapped magnetic fields inside of the superconducting materials decrease the performance of the MKID. The geomagnetism is the static and large magnetic fields. The telescope motion makes modulation of the geomagnetism as well as the modulation of CMB signals. Therefore, we need careful evaluation associating with the telescope rotation. By using a small evaluation system with modulated magnetic fields, we understand impacts the magnetic shield as well as responses of the MKID for the modulated magnetic field. We design the shield based on them. In this presentation, we will report an evaluation of detector responses on the high-speed rotating system along the azimuth. We will also show demonstrations of our own readout electronics which is well matching with the rapid scan modulation strategy.

Paper Details

Date Published: 10 July 2018
Proc. SPIE 10708, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX, 107081I (10 July 2018); doi: 10.1117/12.2314321
Show Author Affiliations
Satoru Mima, RIKEN (Japan)
Jihoon Choi, Institute of Basic Science (Korea, Republic of)
Ricardo Tanausú Génova-Santos, Instituto de Astrofísica de Canarias (Spain)
Makoto Hattori, Tohoku Univ. (Japan)
Masashi Hazumi, High Energy Accelerator Research Organization (Japan)
The Graduate Univ. for Advanced Studies (Japan)
Hikaru Ishitsuka, The Graduate Univ. for Advanced Studies (Japan)
Fumiyasu Kanno, Tohoku Univ. (Japan)
Kenichi Karatsu, Technische Univ. Delft (Netherlands)
Kenji Kiuchi, The Univ. of Tokyo (Japan)
Junta Komine, Kyoto Univ. (Japan)
Ryo Koyano, Saitama Univ. (Japan)
Hiroki Kutsuma, Tohoku Univ. (Japan)
Kyungmin Lee, Korea Univ. (Korea, Republic of)
Makoto Minowa, The Univ. of Tokyo (Japan)
Makoto Nagai, National Astronomical Observatory of Japan (Japan)
Takeo Nagasaki, High Energy Accelerator Research Organization (Japan)
Masato Naruse, Saitama Univ. (Japan)
Shugo Oguri, RIKEN (Japan)
Chiko Otani, RIKEN (Japan)
Rafael Rebolo, Instituto de Astrofísica de Canarias (Spain)
José Alberto Rubiño-Martín, Instituto de Astrofísica de Canarias (Spain)
Yutaro Sekimoto, Institute of Space and Astronautical Science (Japan)
Munehisa Semoto, Saitama Univ. (Japan)
Junya Suzuki, High Energy Accelerator Research Organization (Japan)
Tohru Taino, Saitama Univ. (Japan)
Osamu Tajima, Kyoto Univ. (Japan)
Nozomu Tomita, The Univ. of Tokyo (Japan)
Tomohisa Uchida, High Energy Accelerator Research Organization (Japan)
The Graduate Univ. for Advanced Studies (Japan)
Eunil Won, Korea Univ. (Korea, Republic of)
Mitsuhiro Yoshida, High Energy Accelerator Research Organization (Japan)
The Graduate Univ. for Advanced Studies (Japan)

Published in SPIE Proceedings Vol. 10708:
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX
Jonas Zmuidzinas; Jian-Rong Gao, Editor(s)

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