| Project/Area Number |
17H02883
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Tohoku University (2019)
The University of Tokyo (2017-2018) |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
小川 泉 福井大学, 学術研究院工学系部門, 准教授 (20294142)
山下 雅樹 東京大学, 宇宙線研究所, 特任准教授 (10504574)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥19,500,000 (Direct Cost: ¥15,000,000、Indirect Cost: ¥4,500,000)
Fiscal Year 2019: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2018: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000)
Fiscal Year 2017: ¥11,960,000 (Direct Cost: ¥9,200,000、Indirect Cost: ¥2,760,000)
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| Keywords | 暗黒物質 / アクシオン / マイクロ波空胴 / フォトニック結晶 / 暗黒物質アクシオン / マイクロ波共振空胴 / アクシオン様粒子，ALP / ALP粒子 / 共振空胴 / 共振空洞 |
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| Outline of Final Research Achievements |
In this research, we have developed a large RF resonant cavity which resonates in the fundamental mode (TM010) with photonic crystal technology. A photonic crystal is a structure where metals or high dielectrics are periodically arranged, and the resonance frequency is determined by the spacing. This means that it is possible to enlarge a cavity size and, therefore, make sensitivity of dark matter axion extremely higher, especially at higher RF regime, such as 5-10 GHz region.
In this research, a large photonic crystal cavity (20cm x 20cm x 2cm x 2 cavities) that resonates at 5.7 GHz with TM010 was realized. The size is about 28 times of a simple cylindrical cavity. With this cavity, signal-to-noise ratio in axion search would be increased with factor 28. It could be an epoch-making result for future experiments with RF resonant cavities.
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| Academic Significance and Societal Importance of the Research Achievements |
この宇宙には，我々の知る物質の約5倍の未知の物質「暗黒物質」が存在する．この暗黒物質の正体解明は，現代物理学・天文学における最大の課題である．暗黒物質の最有力候補の１つがアクシオンであり．この他にも，暗黒光子等数多くの候補が存在する．これらアクシオン，暗黒光子の検出では，非常に微弱なマイクロ波を共振空胴を利用して検出する必要がある．しかし，高周波領域では空胴サイズが小さくなり，感度向上が困難であった．本研究では，従来の約30倍の巨大空胴の開発に成功した．これは暗黒物質信号を約30倍することに相当し，マイクロ波を用いた暗黒物質探索において画期的な感度向上を実現する手法の開発に成功したと言える．
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