| 研究課題/領域番号 |
19H00669
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| 研究機関 | 国立研究開発法人量子科学技術研究開発機構 |
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研究代表者 |
PIROZHKOV Alex 国立研究開発法人量子科学技術研究開発機構, 関西光科学研究所 光量子科学研究部, 上席研究員 (00446410)
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| 研究分担者 |
Esirkepov Timur 国立研究開発法人量子科学技術研究開発機構, 関西光科学研究所 光量子科学研究部, 上席研究員 (10370363)
匂坂 明人 国立研究開発法人量子科学技術研究開発機構, 関西光科学研究所 光量子科学研究部, 主幹研究員 (20354970)
小倉 浩一 国立研究開発法人量子科学技術研究開発機構, 関西光科学研究所 光量子科学研究部, 主幹研究員 (30354971)
Pikuz Tatiana 大阪大学, 先導的学際研究機構, 特任准教授(常勤) (20619978)
難波 愼一 広島大学, 先進理工系科学研究科(工), 教授 (00343294)
桐山 博光 国立研究開発法人量子科学技術研究開発機構, 関西光科学研究所 光量子科学研究部, グループリーダー (40354972)
Koga James 国立研究開発法人量子科学技術研究開発機構, 関西光科学研究所 光量子科学研究部, 専門業務員 (70370393)
神門 正城 国立研究開発法人量子科学技術研究開発機構, 関西光科学研究所 光量子科学研究部, 次長 (50343942)
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| 研究期間 (年度) |
2019-04-01 – 2024-03-31
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| キーワード | Coherent x-ray source / New imaging paradigm / BISER / Relativistic plasma / Plasma singularities |
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| 研究実績の概要 |
We performed a joint international experiment in the Central Laser Facility, Rutherford Appleton Lab, UK, with the Astra laser. We enhanced our core technique, the BISER control, so BISER coherent x-ray source brightness at 7 TW laser power was >100x higher than in all the earlier experiments with ~20 TW lasers. Possibly, by this we achieved the Project Goal: significant BISER enhancement by singularity control, however, due to lack of people and diagnostics we do not have an immediate proof of it; we are now continuing our analysis based on limited data and simulations.
Due to COVID-19 almost all of the collaborators could not join the Astra experiment. We worked with 2 (sometimes 3-4) persons only, instead of planned 5-6. We scheduled one more experiment with the J-KAREN-P laser in Feb 2022, but due to COVID it was postponed to Aug 2022. Thus, we are now behind the schedule.
We published 5 refereed papers on the Project's core diagnostics, x-ray spectroscopy and instruments [Ohiro Plas Fus Res 2022];[Barysheva Opt Mat Expr 2021];[Hatano Appl Opt 2021];[Armstrong Rev Sci Instr 2021];[Koike Adv X-Ray Chem Anal Japan 2022].
We performed theoretical analysis of frequency upshifting and focusing of laser reflected by relativistic flying mirror (plasma singularity) and calculated x-ray intensity and e-e+ pair production [Jeong Phys Rev A 2021].
We improved beamline stability and stretcher holder of our J-KAREN-P laser. This will result in better experimental results. We published a refereed paper [Kiriyama High Pow Las Sci Eng 2021].
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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
COVID-19 and war in Ukraine caused delays and problems.
The goals of the Astra-UK experiment were high-resolution imaging of plasma singularities by time-resolved Top View imager and 10 fs Schlieren optical probe. Due to COVID-19, CLF schedule was delayed; further, most of the collaborators could not come. Thus, we could not obtain time-resolved Top View, neither we could get 10 fs optical probe. Thus, we used time-integrated Top View and ~50 fs optical probe, which limited our understanding of physics behind the great (>100x) BISER enhancement. Despite the problems, we managed to improve these compared to the previous year: Top View resolution was enhanced from ~2 um down to sub-um, and the Shadow was upgraded to the more-informative Schlieren.
Due to the COVID, our second experiment planned to Feb-2022 was postponed to Aug-2022.
We developed and tested a new 4D XUV spectrograph: We used a strongly-aperiodic VLS grating to focus the 1st spectral order and get 1D spectral resolution of ~300 and 1D spatial resolution of ~8um, while the defocused 0th order was used for simultaneous 2D angular distribution measurement. This provided new insight into the BISER coherent x-ray source properties.
We acquired a new VLS grating (initially planned for FY2020) optimized for the 1-2 keV spectral range.
We ordered x-ray mirrors necessary for our experiments but the order was canceled due to the sudden war in Ukraine and 1,210,000 yen returned to JSPS. We will order again but this is 43% of our FY2022 budget, which may cause further delays.
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| 今後の研究の推進方策 |
The Astra-UK experiment generated extremely bright BISER and gave new experimental data which revealed that we need much larger-diameter x-ray optics in order to collect the entire BISER x-ray beam. We cannot acquire such large optics as this was not in an initial Project plan. Instead, in 2022 we will estimate the BISER angular distribution and try to select best positions for our small x-ray mirrors. This will not be a real angular distribution measurement (just an estimation) and not the full-beam collection. A real measurement and full collection would cost additionally 1,500-2,000 man yen and could probably result in hundreds of micro-Joule pulse energy with >10^13 photons per shot in soft x-rays, i.e. similar to soft x-ray FEL performance. This can change the entire field of coherent x-rays applications but still remains an outstanding scientific problem and a #1 goal for future Projects.
In accordance with the Project Goals, we will use our Top View and Schlieren probe for obtaining in-depth information on relativistic plasma singularities and with this plan to obtain the Project Goals, i.e. achieve the Filamentation and Self-Focusing control for further BISER brightness enhancement.
Based on previous years' experience [Ohiro et al Plas Fus Res 2022] we will improve the Photoelectron and Auger beamline and the Magnetic Bottle Electron Spectrometer (MBES) to significantly increase the S/N ratio.
We will continue PIC and nozzle gas dynamic simulations for Astra-UK experiment analysis and guiding the planned J-KAREN-P experiments.
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