Mr. Junta Komine Profile

Junta Komine

at Kyoto Univ

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Author

Publications (2)

Proceedings Article | 13 December 2020 Poster + Presentation + Paper

On-site performance of GroundBIRD, a CMB polarization telescope for large angular scale observations

Shunsuke Honda, Jihoon Choi, Ricardo Tanausu Génova-Santos, Makoto Hattori, Masashi Hazumi, Takuji Ikemitsu, Hidesato Ishida, Hikaru Ishitsuka, Yonggil Jo, Kenichi Karatsu, Kenji Kiuchi, Junta Komine, Ryo Koyano, Hiroki Kutsuma, Kyungmin Lee, Satoru Mima, Makoto Minowa, Joonhyeok Moon, Makoto Nagai, Takeo Nagasaki, Masato Naruse, Shugo Oguri, Chiko Otani, Michael Peel, Rafael Rebolo-López, José Alberto Rubiño-Martín, Yutaro Sekimoto, Yoshinori Sueno, Junya Suzuki, Tohru Taino, Osamu Tajima, Nozomu Tomita, Yuta Tsuji, Tomohisa Uchida, Eunil Won, Mitsuhiro Yoshida

Proceedings Volume 11445, 114457Q (2020) https://doi.org/10.1117/12.2560918

KEYWORDS: Telescopes, Polarization, Sensors, Observatories, Microwave radiation, Field programmable gate arrays, Telecommunications, Optical instrument design, Atmospheric sensing, Detector arrays

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Proceedings Article | 10 July 2018 Presentation

Performance evaluation of MKDs on a high-speed rotating system for CMB telescope: GroundBIRD (Conference Presentation)

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

Proceedings Volume 10708, 107081I (2018) https://doi.org/10.1117/12.2314321

KEYWORDS: Telescopes, Magnetism, Modulation, Microwave radiation, Polarization, Sensors, Optical scanning systems, Inductance, Atmospheric optics, Observatories

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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.

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