共查询到20条相似文献,搜索用时 15 毫秒
1.
Influence of the Inner Diameters of Capillary on the Z‐Pinch Plasma of the Capillary Discharge Soft x‐ray Laser 下载免费PDF全文
Shan Jiang Yong‐peng Zhao Huai‐yu Cui Lian‐bo Li Yu‐jie Ding Wen‐hong Zhang Wei Li 《等离子体物理论文集》2015,55(8):570-577
In this paper, the effects of inner diameters on the Z‐pinch plasma of capillary discharge soft x‐ray laser were investigated with the 3.2 mm and 4.0 mm inner diameter alumina capillaries. The intensities of the laser emitted from the 3.2 mm and 4.0 mm inner diameter alumina capillaries were measured under different initial pressures. To understand the underlying physics of the experimental measurements, the Z‐pinch plasma simulations had been conducted with a one‐dimensional cylindrical symmetry Lagrangian magneto‐hydrodynamics (MHD) code. The parametric studies of Z‐pinch plasma, such as the electron temperature, the electron density and the Ne‐like Ar ion density, were performed with the MHD code. With the experimental and the simulated results, the discussions had been conducted on the Z‐pinch plasma of Ne‐like Ar 46.9 nm laser with the 3.2 mm and 4.0 mm inner diameter alumina capillaries. The analysis had been made on the difference of the gain coefficients under the optimum pressures with both capillaries. Then, the effects of inner diameters on the optimum pressure and the pressure domain were analyzed. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
2.
以哈尔滨工业大学可调谐激光技术国家重点实验室中的Marx发生器的放电脉冲波形为基础,理论上模拟计算了在不同放电参数下充氩气的毛细管放电产生的等离子体状态和类氖氩离子3p_3s跃迁线的增益系数的时空演变过程。中心模型中,选取内径为3.1 mm 的陶瓷毛细管并充入初始密度为1.07×10-6g·cm-3的氩气,电流脉冲峰值为27.81 kA,脉冲宽度为61.4 ns。改变放电参数进行模拟,结果表明:上升前沿越陡,则增益系数越大,电流脉冲上升时间在20~40 ns,电流峰值在25~40 kA,电流脉冲宽度在50~70 ns范围内,毛细管放电产生的等离子体状态比较理想,可获得较高的增益系数。 相似文献
3.
4.
5.
在一台毛细管快放电软x射线激光实验装置上,在相同主脉冲条件下(电流峰值18—30kA,半周期80ns),通过观测放电产生的软x射线辐射,研究了该装置固有的高幅值(2—5kA)和外加的低幅值(10—20A)两种预脉冲,对聚乙烯毛细管和高纯度陶瓷毛细管(99.9%)放电的管壁烧蚀及等离子体状态的影响.采用装置固有的几kA预脉冲和聚乙烯毛细管,放电 过程中产生了大量的管壁烧蚀,并且这种情况下的等离子体均匀性差,没有可能获得激光输 出.而采用20A的预脉冲和高纯度陶瓷毛细管,管壁烧蚀量大大减少,预电离等离子体的均匀 性好,在这种情况下,实验上利用x射线二极管观测到了激光尖峰信号.
关键词:
预脉冲
毛细管放电
软x射线激光 相似文献
6.
《X射线光谱测定》2003,32(5):402-407
Micro‐synchrotron radiation x‐ray fluorescence has been used to examine the metal distribution across an entire black spruce stem. The results show the individual elements to be transported and sequestered in different ways so that apparent elemental mobility within the stem changes from element to element. The results suggest that a detailed knowledge of the behavior of each element is required before pollution chronologies can be inferred from dendroanalysis. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
7.
S. Barnwal Y. B. S. R. Prasad S. Nigam K. Aneesh M. L. Sharma R. P. Kushwaha P. K. Tripathi P. A. Naik J. A. Chakera C. P. Navathe P. D. Gupta 《Applied physics. B, Lasers and optics》2014,117(1):131-139
Intense lasing had been obtained from argon plasma in the soft X-ray region from a capillary discharge plasma system. Different diagnostics have been used to characterize the lasing properties by recording the temporal, spatial, and spectral profiles of the emission. The divergence measurement indicates that the soft X-ray laser beam has good directionality with a divergence of 3.5 mrad. The spectrum of the laser beam measured using a transmission grating showed intense lasing line at 46.9 nm. Diffraction orders as high as 10th orders were observed. The temporal profile recorded with a vacuum diode showed a distinct laser peak with a pulse width ~1.2 ns (FWHM). In addition, the coherence of the X-ray laser beam was also confirmed from the high-contrast interference fringes (visibility ~85 %) recorded using double slits. 相似文献
8.
9.
10.
利用x射线二极管(XRD),实验上测量了毛细管放电激励下类氖氩469nm软x射线激光的尖 峰信号. 改变毛细管的充气气压和主脉冲放电电流,研究了激光尖峰的产生时间随实验参数 的变化情况. 实验结果表明,激光产生于主脉冲电流波形的前沿,此时的主脉冲电流是其峰 值的65%—75%. 增加毛细管充气气压或者减小主脉冲峰值电流,激光的产生时间将会稍有延 迟. 同时改变毛细管充气气压时,激光尖峰信号在42Pa存在最大值.
关键词:
毛细管放电
软x射线激光
激光产生时间 相似文献
11.
以哈尔滨工业大学可调谐激光技术国家重点实验室中的Marx发生器的放电脉冲波形为基础,理论上模拟计算了在不同放电参数下充氩气的毛细管放电产生的等离子体状态和类氖氩离子3p_3s跃迁线的增益系数的时空演变过程。中心模型中,选取内径为3.1 mm 的陶瓷毛细管并充入初始密度为1.07×10-6g·cm-3的氩气,电流脉冲峰值为27.81 kA,脉冲宽度为61.4 ns。改变放电参数进行模拟,结果表明:上升前沿越陡,则增益系数越大,电流脉冲上升时间在20~40 ns,电流峰值在25~40 kA,电流脉冲宽度在50~70 ns范围内,毛细管放电产生的等离子体状态比较理想,可获得较高的增益系数。 相似文献
12.
V. G. Kohn 《Journal of synchrotron radiation》2012,19(1):84-92
The possibility of using a parabolic refractive lens with initial X‐ray free‐electron laser (XFEL) pulses, i.e. without a monochromator, is analysed. It is assumed that the measurement time is longer than 0.3 fs, which is the time duration of a coherent pulse (spike). In this case one has to calculate the propagation of a monochromatic wave and then perform an integration of the intensity over the radiation spectrum. Here a general algorithm for calculating the propagation of time‐dependent radiation in free space and through various objects is presented. Analytical formulae are derived describing the properties of the monochromatic beam focused by a system of one and two lenses. Computer simulations show that the European XFEL pulses can be focused with maximal efficiency, i.e. as for a monochromatic wave. This occurs even for nanofocusing lenses. 相似文献
13.
Development of picosecond time‐resolved X‐ray absorption spectroscopy by high‐repetition‐rate laser pump/X‐ray probe at Beijing Synchrotron Radiation Facility 下载免费PDF全文
Hao Wang Can Yu Xu Wei Zhenhua Gao Guang-Lei Xu Da-Rui Sun Zhenjie Li Yangfan Zhou Qiu-Ju Li Bing-Bing Zhang Jin-Qiang Xu Lin Wang Yan Zhang Ying-Lei Tan Ye Tao 《Journal of synchrotron radiation》2017,24(3):667-673
A new setup and commissioning of transient X‐ray absorption spectroscopy are described, based on the high‐repetition‐rate laser pump/X‐ray probe method, at the 1W2B wiggler beamline at the Beijing Synchrotron Radiation Facility. A high‐repetition‐rate and high‐power laser is incorporated into the setup with in‐house‐built avalanche photodiodes as detectors. A simple acquisition scheme was applied to obtain laser‐on and laser‐off signals simultaneously. The capability of picosecond transient X‐ray absorption spectroscopy measurement was demonstrated for a photo‐induced spin‐crossover iron complex in 6 mM solution with 155 kHz repetition rate. 相似文献
14.
15.
毛细管放电Z箍缩等离子体软X射线激光器近几年发展非常迅速,已经获得了在46.9nm的波长上近毫焦量级的激光输出,重复频率达到了4Hz.利用这种软X射线激光在等离子诊断、物质烧熔等方面已开展了初步的应用实验研究.文章介绍了毛细管放电泵浦的两种物理机制,阐述了类氖氩离子2p^53p^1S0-2p^53s^1P1能级间粒子数反转的形成及毛细管放电等离子体柱的演变过程.深入理解这些物理过程,对发展毛细管放电软X射线激光将起到积极作用。 相似文献
16.
Characteristics of a Ne-like Ar 46.9-nm soft X-ray laser in capillary discharge at a low Ar pressure
A capillary discharge-pumped Ne-like Ar 46.9-nm soft X-ray laser at a low Ar pressure (28–46 Pa) is proven. To our knowledge, this is the first time an XRD laser output in the condition of the low threshold of a main-current pulse spike (20–21 kA) is demonstrated. The Al2O3 ceramic capillary tube is 20 cm in length (Mo electrode is 4 cm in length) and 3 mm in diameter. The maximum laser energy of the precalibrated XRD is 3.5 μJ. The maximum gain coefficient g = 0.46 cm?1, the maximum gain-length product is 8.28, the beam divergence is 5.4 mrad, and the laser pulse width is 1.65 ns. In addition, the results show that the laser plasma column became difficult to Z-pinch with a increasing Ar pressure, its Z-pinching state of a higher Ar pressure fluctuates more intensely than that of a lower pressure by analyzing the scattering of the delay time between the pre-and main-current pulse. 相似文献
17.
M. I. Mazuritskiy 《Journal of synchrotron radiation》2012,19(1):129-131
Here, soft X‐ray synchrotron radiation transmitted through microchannel plates is studied experimentally. Fine structures of reflection and XANES Si L‐edge spectra detected on the exit of silicon glass microcapillary structures under conditions of total X‐ray reflection are presented and analyzed. The phenomenon of the interaction of channeling radiation with unoccupied electronic states and propagation of X‐ray fluorescence excited in the microchannels is revealed. Investigations of the interaction of monochromatic radiation with the inner‐shell capillary surface and propagation of fluorescence radiation through hollow glass capillary waveguides contribute to the development of novel X‐ray focusing devices in the future. 相似文献
18.
19.
X‐ray free‐electron lasers (XFELs) generate sequences of ultra‐short spatially coherent pulses of X‐ray radiation. A diffraction focusing spectrometer (DFS), which is able to measure the whole energy spectrum of the radiation of a single XFEL pulse with an energy resolution of ΔE/E? 2 × 10?6, is proposed. This is much better than for most modern X‐ray spectrometers. Such resolution allows one to resolve the fine spectral structure of the XFEL pulse. The effect of diffraction focusing occurs in a single‐crystal plate due to dynamical scattering, and is similar to focusing in a Pendry lens made from a metamaterial with a negative refraction index. Such a spectrometer is easier to operate than those based on bent crystals. It is shown that the DFS can be used in a wide energy range from 5 keV to 20 keV. 相似文献
20.
Motohiro Suzuki Yuichi Inubushi Makina Yabashi Tetsuya Ishikawa 《Journal of synchrotron radiation》2014,21(3):466-472
A diamond phase retarder was applied to control the polarization states of a hard X‐ray free‐electron laser (XFEL) in the photon energy range 5–20 keV. The horizontal polarization of the XFEL beam generated from the planar undulators of the SPring‐8 Angstrom Compact Free‐Electron Laser (SACLA) was converted into vertical or circular polarization of either helicity by adjusting the angular offset of the diamond crystal from the exact Bragg condition. Using a 1.5 mm‐thick crystal, a high degree of circular polarization, 97%, was obtained for 11.56 keV monochromatic X‐rays, whereas the degree of vertical polarization was 67%, both of which agreed with the estimations including the energy bandwidth of the Si 111 beamline monochromator. 相似文献