2022 Fiscal Year Final Research Report

Development of Ring Structure Forebaffles that Effectively Reduce Ground Signal Systematics in CMB Telescopes

Research Project

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Project/Area Number	20K14483
Research Category	Grant-in-Aid for Early-Career Scientists
Allocation Type	Multi-year Fund
Review Section	Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
Research Institution	Japan Aerospace EXploration Agency (2021-2022) The University of Tokyo (2020)
Principal Investigator	Matsuda Frederick 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, 特任助教 (40867032)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	宇宙マイクロ波背景放射 / インフレーション / CMB / 光学 / バッフル
Outline of Final Research Achievements	The main goal of this research is to develop a ring structured forebaffle for ground-based cosmic microwave background (CMB) experiments that can effectively reduce ground signal systematics during observations. Based on optics simulations, we showed that ground signal systematics can be reduced to 0.005% using an optimized ring structured forebaffle. We were also able to identify the various fabrication risks related to structural integrity and cost. Even though we were not able to deploy a ring structured forebaffle in this research, based on our research findings, we developed an improved standard forebaffle for the Simons Observatory small aperture telescope. Through this up-grade development, we were able to mitigate to a certain extent the fabrication risks that were common to both the development of the ring structured forebaffle and improved standard forebaffle. Using a similar design strategy, we aim to deploy a ring structured forebaffle for future CMB telescopes.
Free Research Field	宇宙物理学
Academic Significance and Societal Importance of the Research Achievements	本研究の学術的意義は、次世代CMB実験において、地形反射により計測器に侵入するシグナル汚染（迷光）をどのように低減するかは大きな課題である点です。高い統計感度を持つ次世代望遠鏡にとって、地形反射は大きな系統誤差となりうるため、望遠鏡のバッフル構造を改良し系統誤差を抑制することは必須である。そして、望遠鏡の外部バッフルとしてリングバッフル構造を応用するのはCMB地上実験では新たな試みであるため、本成果はリングバッフルの実用に向けた重要な研究開発である。将来的なリングバッフルの実装により、CMB地上実験の飛躍的な感度向上を目指す。