| 研究課題/領域番号 |
26707031
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| 研究機関 | 独立行政法人日本原子力研究開発機構 |
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研究代表者 |
PIROZHKOV Alex 独立行政法人日本原子力研究開発機構, 原子力科学研究部門 量子ビーム応用研究センター, 研究副主幹 (00446410)
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| 研究期間 (年度) |
2014-04-01 – 2018-03-31
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| キーワード | コヒーレントX線放射 / レーザー光の高次高調波 / 相対論的電子スパイク / レーザー光とプラズマの相互作用 / 超高強度レーザー / 相対論的プラズマ |
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| 研究実績の概要 |
In FY2014 I made a good progress in my research on the ultra-bright x-ray harmonic comb by relativistic plasma singularity.
As it was the first year of the Project, it was devoted mostly to the design of the future experiments, taking into account the previous experience. In accordance with the original plan, I designed and purchased the positioning stages for the razor blade to be inserted into a supersonic jet, which is one of the central parts of the Project. Also in accordance with the plan, I designed scheme and diagnostics for the Petawatt experiment planned with our upgraded J-KAREN-P laser in the 2nd half of the FY2015.
I have published a comprehensive paper about the novel harmonics generation regime in the high-impact open-access journal, the New Journal of Physics. I made 1 invited and 3 oral presentations devoted to the new ultra-bright coherent x-ray source at 3 international and 1 domestic conferences.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
(1) In preliminary experiments I used various motorized stages and controllers, and some of them had stability and stiffness problems due to laser operation and supersonic gas stream. Based on this experience, I carefully selected the XYZ motorized stages and controller to be used in this Project for the razor blade positioning in a supersonic gas jet. I purchased the set including X, Y, and Z linear stages, cables, and 4-stage controller; these were modified to be vacuum-compatible using vacuum grease and custom feed-through flange designed for our target chamber.
(2) I designed several XUV and x-ray spectrographs and imaging lines to be used with the new Petawatt mode of our J-KAREN-P laser. These improved designs took into account problems which I encountered previously. In particular, they are much less vulnerable to laser damage due to the use of pre-filters and have better imaging properties due to aberration control.
(3) I continued fundamental research on the new harmonics generation regime and published a long paper with the summary of experiments, new model, and theory [Pirozhkov et al., New Journal of Physics 16 (9), 093003-30 (2014)].
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| 今後の研究の推進方策 |
(1) I will finish re-construction of x-ray diagnostics and other preparations for experiments with Petawatt laser power. This includes multi-channel and single-channel grazing-incidence flat-field spectrographs, imaging XUV spectrographs, and high spatial resolution XUV imaging lines.
(2) I will perform first experiments with our J-KAREN-P laser after the upgrade (1 PW, 0.1 Hz). I will implement the density jump scheme using the razor blade and demonstrate the control of harmonics generation.
(3) I will use a deformable mirror recently installed at the J-KAREN-P laser to improve the focal spot quality. There is a room for 2-3 times higher irradiance because previously it was ~4 times smaller than the diffraction limit. According to the preliminary experiments, this will result in a dramatic improvement of the harmonic yield.
(4) There may be a possibility to perform experiment on high-power laser abroad with my foreign collaborators (Prof. D. Neely, CLF RAL, UK, 0.5 PW Astra Gemini laser; Drs. I. W. Choi and I. J. Kim, APRI GIST, Korea, PW laser)
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| 次年度使用額が生じた理由 |
Originally, I planned to order the following expensive equipment in FY2014: (1) stiff vacuum XYZ motorized stages for blade positioning, (2) supersonic nozzle set, and (3) optical blocking filters. In FY2014 I ordered the stages (1), as planned, using the single-year budget. However, because the experiment on harmonics generation with our J-KAREN-P laser was scheduled to the 2nd half of the FY2015, I decided to postpone ordering of (2) and (3) to FY2015. In this case, the optical blocking filters will not be aged unnecessarily, i.e. they will be newer in the experiment. Also, I will know more precisely the laser performance in FY2015, which will allow me to order the supersonic nozzles specially tailored for the desired interaction parameters.
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| 次年度使用額の使用計画 |
I plan to spend ~800,000 yen to the supersonic nozzle set (diameters 0.3, 0.5, and 1 mm) and the remaining money to optical blocking filters for the photon energy > 60 eV (0.16 μm Zr/Al multilayer free-standing filters, diameter 22 mm) and large-diameter filters for photon energy > 400 eV and 40-70 eV (0.2 μm Al filters with support mesh, diameter 50 mm).
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| 備考 |
The URL refers to the video abstract of the paper A S Pirozhkov et al, "High order harmonics from relativistic electron spikes," New Journal of Physics 16 (9), 093003-30 (2014).
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