| 研究課題/領域番号 |
21H04476
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| 研究機関 | 国立天文台 |
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研究代表者 |
LEONARDI MATTEO 国立天文台, 重力波プロジェクト, 特別客員研究員 (90816448)
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| 研究分担者 |
麻生 洋一 国立天文台, 重力波プロジェクト, 准教授 (10568174)
Zhao Yuhang 東京大学, 宇宙線研究所, 特任研究員 (70897834)
道村 唯太 東京大学, 大学院理学系研究科(理学部), 客員共同研究員 (80747006)
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| 研究期間 (年度) |
2021-04-05 – 2024-03-31
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| キーワード | quantum noise / gravitational wave / KAGRA / filter cavity / freq. dep. squeezing |
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| 研究実績の概要 |
In FY2022 several steps were taken in order to improve the stability of the filter cavity. The use of a bichromatic control for the filter cavity length, alignment and incident beam pointing degree of freedoms was finalized after being studied since FY2021. This was a crucial step in understanding the relationship between infrared lock and green lock. A paper on Physical Review D was published on it. With this control, a factor of 6 improvement on the filter cavity detuning was achieved, bringing this parameter within the requirement for implementation in KAGRA. In addition, the scheme proposed in the paper was officially adopted also by the Italian-French gravitational wave detector named Virgo. Another step done to improve the stability of the filter cavity was also achieved which was the experimental demonstration of the lock of the filter cavity via the coherent control sidebands scheme proposed theoretically by our group in 2019. The results of this demonstration have also been published in Physical Review D.
In addition, several steps have been performed to reduce the impact of optical losses. In particular, the new low losses Faraday isolator has been characterized and the new low loss Optical Parametric Oscillator has been realized and characterized. The new low losses component will allow for a better characterization of scattering losses which will in turn lead to better understanding the role of polishing specs in the filter cavity system.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
The aging of TAMA electronics requested a small adjustment of schedule to refurbish the failing parts. Unfortunately, mainly due to the difficulties in procurement of components due to the ending of the Covid pandemic as well as the rampaging Russo-Ukrainian war, created some delays.
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| 今後の研究の推進方策 |
The activity in FY2023 will start by finalizing the scattering light characterization and installation of new low losses components (in-vacuum FI and OPO). This activities will give insight in the source of phase noise and finally define the requirements for substrates and coatings. This items will be procured after this finalization.
In parallel the design of new generation suspension will be done and the fabrication of such suspensions will be performed. The characterization of the first prototype of the new suspension is planned in the second half of FY2023. Finally, due to the aging of current control electronics, several components are planned to be replaced or improved along the course of the year.
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