宇宙物理学研究系

高倉 隼人

Hayato TAKAKURA

基本情報

所属
国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 宇宙物理学研究系 宇宙航空プロジェクト研究員

研究者番号
10980948
ORCID ID
 https://orcid.org/0000-0001-9823-1920
J-GLOBAL ID
202001020525555639
researchmap会員ID
R000014175

研究キーワード

 2

主要な論文

 22
  • Hayato Takakura, Yutaro Sekimoto, Kimihide Odagiri, Rion Takahashi, Fumiya Miura, Frederick T. Matsuda, Shugo Oguri
    Space Telescopes and Instrumentation 2024: Optical, Infrared, and Millimeter Wave 207-207 2024年8月23日  筆頭著者
  • Fumiya Miura, Hayato Takakura, Yutaro Sekimoto, Junji Inatani, Frederick Matsuda, Shugo Oguri, Shogo Nakamura
    Applied Optics 2024年8月8日  査読有り
  • Ryo Nakano, Hayato Takakura, Yutaro Sekimoto, Junji Inatani, Masahiro Sugimoto, Shugo Oguri, Frederick Matsuda
    Journal of Astronomical Telescopes, Instruments, and Systems 9(02) 2023年4月19日  査読有り
  • Hayato Takakura, Yutaro Sekimoto, Junji Inatani, Shingo Kashima, Masahiro Sugimoto, Ryo Nakano, Ryo Nagata
    Journal of Astronomical Telescopes, Instruments, and Systems 9(02) 2023年4月12日  査読有り筆頭著者
  • Hayato Takakura, Ryo Nakano, Yutaro Sekimoto, Junji Inatani, Masahiro Sugimoto, Frederick T. Matsuda, Shugo Oguri
    Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave 12180 2022年8月27日  筆頭著者
    Suppression of straylight is one of the challenges in the optical design of a wide-field-of-view telescope. It contaminates the weak target signal with radiation from strong sources at angles far from the observing direction. We evaluated the optical design of a crossed-Dragone telescope, the LiteBIRD Low-Frequency Telescope (LFT), which has 18 degrees x 9 degrees field of view. We measured a 1/4-scaled antenna of the LFT at accordingly scaled frequencies of 160-200 GHz (corresponding to 40-50 GHz for the full-scale LFT), for the feed at the center and the edges of the focal plane. To separate straylight components, we computed the time profiles of the aperture fields with similar to 0.1 ns resolution by inverse Fourier transformation of the measured frequency spectra and applied time gating to them. We identified far-sidelobe components in the time-gated antenna beam patterns whose arrival time and angular direction are consistent with straylight predicted by a ray-tracing simulation. The identified far-sidelobe components include straylight reduced but reflected inside the front hood and straylight with multiple reflections without intercepted by the front hood. Their intensities are less than the -56 dB level, which is the far-sidelobe knowledge requirement for the LFT.
  • Hayato Takakura, Yutaro Sekimoto, Junji Inatani, Shingo Kashima, Hiroaki Imada, Takashi Hasebe, Toru Kaga, Yoichi Takeda, Norio Okada
    IEEE Transactions on Terahertz Science and Technology 9(6) 598-605 2019年11月  査読有り筆頭著者
    © 2019 IEEE. Polarization of the cosmic microwave background (CMB) has crucial information on the inflationary universe. To detect these signals, it is necessary to suppress far sidelobes of a telescope, which contaminate the CMB signals with strong foreground radiation, such as the Galactic plane. LiteBIRD is the only funded CMB observation satellite for the 2020s, and the low frequency telescope (LFT; 34-161 GHz) is one of its telescopes. We measured near-field antenna patterns of the LFT using its 1/4-scaled model and examined far sidelobes up to 60° from the peaks. To cover the 20° field of view of the LFT, we investigated the antenna patterns at the edges of the focal plane as well as at the center. The measurement frequencies were 140-220 GHz, which correspond to the lowest bands (35-55 GHz) of the full-scale LFT. The measurements were consistent with the simulated far-sidelobe patterns at least -50 dB level, and showed that far sidelobes for two orthogonal polarization directions are consistent with each other down to -40 dB level. We also measured the cross-polarization patterns, and their peak level was less than -20 dB.

主要なMISC

 8

主要な講演・口頭発表等

 8

共同研究・競争的資金等の研究課題

 3