2021 Fiscal Year Annual Research Report
大型低温重力波望遠鏡KAGRAのための圧搾真空源の開発、導入及び検証
| Project/Area Number |
20F20803
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| Research Institution | National Astronomical Observatory of Japan |
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Principal Investigator |
LEONARDI MATTEO 国立天文台, 重力波プロジェクト, 助教 (90816448)
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| Co-Investigator(Kenkyū-buntansha) |
EISENMANN MARC 国立天文台, 重力波プロジェクト, 外国人特別研究員
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| Project Period (FY) |
2020-11-13 – 2023-03-31
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| Keywords | KAGRA / filter cavity / freq. dep. squeezing / sapphire / optical absorption / birefringence |
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| Outline of Annual Research Achievements |
From April 2021, Dr. Eisenmann participated to the characterization and improvement of the Filter Cavity (FC) controls.
A factor 6 improvement on the FC detuning fluctuations was achieved. This improvement is enough to not limit future KAGRA sensitivity. This result, which was published this year, was achieved by using bichromatic controls of the FC based on beam pointing and automatic alignment. However, the use of this bichromatic controls has also some limitations that can be mitigated by using a new control scheme that was demonstrated as well with a publication in preparation. As one of the core members of the KAGRA Filter Cavity project, he also found good length and mirror radius of curvature to optimize its performances within KAGRA infrastructure.
He also participated to the characterization of sapphire substrates in order to better understand and improve KAGRA test-masses performances. The absorption of several samples have been measured in order to find good sapphire manufacturers for future KAGRA test-masses. The experimental setup has been also modified to be able to measure substrates birefringence. We found correlations between absorption and birefringence and an article is currently under review.
He was also involved in the cleaning and characterization of a KAGRA test-masses. This setup was used to assess the good cleanliness and the mirror has been already reinstalled in KAGRA. He participated to the development of a website to quickly gather and access the main parameters of the detector. It is now online and used by the collaboration.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Dr. Eisenmann successfully participated to the characterization and improvement of Filter Cavity controls. Such activity culminated in two papers (one already published on PRD, another under review) of which he is co-author.
Thanks to his past experience, he provided very valuable contribution to the KAGRA Filter Cavity project and assumed leadership position within the group.
He was also extremely valuable in the research on sapphire absorption and birefrincence. Also in this case, the activity culminated in one research paper (currently under review at Scientific Reports) of which he is a co-author.
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| Strategy for Future Research Activity |
For the Filter Cavity, Dr. Eisenmann plans to investigate and possibly mitigate the effects of scattered light that limits our system at low-frequency. He will participate to the implementation of a new alignment control scheme that should improve a lot our system stability.
For the KAGRA Filter Cavity, he will be involved in finalizing the Filter Cavity optical design. He also plans to contribute to the design of the optical path between it and the KAGRA interferometer.
As KAGRA needs to select soon its new test-masses, he will participate to this selection process by measuring the absorption and birefringence of new large size substrates. He will also investigate the effects of annealing on the absorption levels. An upgrade of the setup is also foreseen to allow quicker measurements.
Finally, he plans to join KAGRA alignment and controls commissioning.
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Research Products
(1 results)
