Collimator of the ultra-lightweight x-ray telescope for the GEO-X mission

Kumi Ishikawa; Takatoshi Murakawa; Daiki Ishi; Masaki Numazawa; Aoto Fukushima; Sae Sakuda; Tomoki Uchino; Ayata Inagaki; Hiromi Morishita; Yoko Ueda; Luna Sekiguchi; Yukine Tsuji; Yuichiro Ezoe

doi:10.1117/12.2631464

31 August 2022 Collimator of the ultra-lightweight x-ray telescope for the GEO-X mission

Kumi Ishikawa, Takatoshi Murakawa, Daiki Ishi, Masaki Numazawa, Aoto Fukushima, Sae Sakuda, Tomoki Uchino, Ayata Inagaki, Hiromi Morishita, Yoko Ueda, Luna Sekiguchi, Yukine Tsuji, Yuichiro Ezoe

Author Affiliations +

Proceedings Volume 12181, Space Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray; 121816O (2022) https://doi.org/10.1117/12.2631464
Event: SPIE Astronomical Telescopes + Instrumentation, 2022, Montréal, Québec, Canada

Conference Poster

Abstract

GEO-X is a small satellite mission in near moon orbit to visualize the Earth’s magnetosphere. Since the Earth is a bright x-ray source, its x-rays have a potentially effect on the GEO-X observations. Fluxes of the unexpected x-rays, stray lights, and of the GEO-X signal can be estimated. In order to estimate the stray light effect on the GEO-X FOV, we carried out a ray-tracing simulation and calculated the signal-to-noise ratio for elongations from the Earth. The S/N ratio shows a range depending on signal flux. The signal estimated by MHD simulations is smaller than estimation based on the typical observation. When we apply the small signal flux, the S/N ratio is <10 at 7 deg elongation of the GEO-X FOV from the Earth in an orbital altitude of 60R_E. In order to improve the S/N ratio, there are two ways, installing a collimator in front of the optics and adjusting the observation position to obtain a large elongation. The ray-tracing simulation reveals that the collimator with 30 µm pore width and 300 µm thickness can improve the S/N ratio. The S/N ratio with the collimator can achieve >10 when the elongation is 7 deg in the orbital altitude of 60 R_E. A sample collimator was fabricated by a Si dry etching. Difference of the pore width from the designed value was occurred. Since the difference can lead to extra photon loss, a trade-off study between fabrication precision and observation position is important.

Citation Download Citation

Kumi Ishikawa, Takatoshi Murakawa, Daiki Ishi, Masaki Numazawa, Aoto Fukushima, Sae Sakuda, Tomoki Uchino, Ayata Inagaki, Hiromi Morishita, Yoko Ueda, Luna Sekiguchi, Yukine Tsuji, and Yuichiro Ezoe "Collimator of the ultra-lightweight x-ray telescope for the GEO-X mission", Proc. SPIE 12181, Space Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray, 121816O (31 August 2022); https://doi.org/10.1117/12.2631464

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