共查询到18条相似文献,搜索用时 187 毫秒
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百太瓦飞秒激光驱动复合靶产生质子的特性研究 总被引:1,自引:0,他引:1
在SILEX-I激光装置上实验研究了超强超短激光与Au/CH复合靶相互作用中在靶背法线方向发射的质子束的空间分布特征。 保持复合靶前表面的Au厚度不变,质子束流随着后表面的C8H8层厚度的增加而减小, 同时质子空间分布呈现环状、成丝和圆盘状分布。 实验没有发现高于2.75 MeV的高能质子产生。实验进一步完善了超短超强激光等离子体相互作用的物理模型。Proton beam behavior at the normal direction of the rear surface of the target produced from ultra intense short pulse laser irradiated Au/CH double layers targets was explored on SILEX I laser facility. With the same thickness of Au layer,the proton beam flux decreases with the increasing of CH layer thickness,and the corresponding spatial profile of proton beam shows ring, filament,and disc like distribution. The energy of proton beam was not beyond 2.75 MeV in our experiment. 相似文献
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K-shell X-ray emission from a Cu nanowire target irradiated by an ultraintense femtosecond laser pulse is studied using an elliptically bent quartz crystal and imaging plate. The designed bent crystal spectrometer has better spectral resolution, which is higher than 1 000. The absolute Kα radiation photon yields are obtained from the experimental results and the Monte-Carlo model. The conversion efficiency of the Cu Kα line is estimated to be 0.019% from the interaction of 4 J, 50-fs laser pulse irradiated on a Cu nanowire target. The high yield of K shell X-ray has important applications in X-ray emission source. 相似文献
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A vacuum ultraviolet VUV spectrometer with spatial and temporal resolutions was presented in this paper. The sensitivity of the spectrometer has been calibrated in situ by using the VUV bremsstrahlung continuum radiation of the HL-2A plasma. The sensitivity coefficients of two gratings were given. The absolute density profile of carbon radiation was thus obtained based on the absolutely radial profile measurement of carbon radiation. 相似文献
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Time-resolved measurement of atomic emission enhancement by fs--ns dual-pulsed laser-induced breakdown spectroscopy 下载免费PDF全文
Time-resolved measurement of atomic emission enhancement is performed by using a
500-fs KrF laser pulse incident upon a high density supersonic O_{2} gas jet,
synchronized with an orthogonal ns frequency-doubled Nd:YAG laser pulse. The
ultra-short pulse serves as an igniter of the gas jet, and the subsequent ns-laser
pulse significantly enhances the atomic emission. Analysis shows that the
contributions to the enhancement effect are made mainly by the bremsstrahlung
radiation and cascade ionization. 相似文献
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MA Yan-Liang OUYANG Xiao-Ping ZHANG Jing-Wen ZHANG Zhong-Bing PAN Hong-Bo CHEN Liang LIU Lin-Yue 《中国物理C(英文版)》2010,34(3)
In this paper, properties on pulsed radiation detections of ZnO:Ga crystal grew by a magnetron sputtering method were studied. The time response to pulsed laser,pulsed hard X rays and single α particles, the energy response to pulsed hard X ray, the scintillation efficiency to γ rays, the response to pulsed proton, and the relations of the light intensity varied with the proton energy were measured and analyzed in detail. Results show that the ZnO:Ga crystal has potential applications in the regime of pulse radiation detection . 相似文献
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In this paper, properties on pulsed radiation detections of ZnO:Ga crystal grew by a magnetron sputtering method were studied. The time response to pulsed laser, pulsed hard X rays and single α particles, the energy response to pulsed hard X ray, the scintillation efficiency to γ rays, the response to pulsed proton, and the relations of the light intensity varied with the proton energy were measured and analyzed in detail. Results show that the ZnO:Ga crystal has potential applications in the regime of pulse radiation detection. 相似文献
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《中国光学与应用光学文摘》2007,(4)
O434.122007043716光子计数型CCD测量激光等离子体X射线=Measure-ment of X ray in interaction of laser plasmas by photoncounting CCD[刊,中]/熊勇(中物院激光聚变研究中心.四川,绵阳(621900)),黄文忠…//强激光与粒子束.?2007,19(2).?271-273介绍了光子计数型电荷耦合器件 相似文献
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Experimental observation of ionization and shock fronts in foam targets driven by thermal radiation 下载免费PDF全文
The behaviours of ionization and shock propagation in
radiatively heated material is crucial for the understanding of
indirect drive inertial confinement fusion as well as some
astrophysics phenomena. In this work, radiation field with a peak
temperature of up to 155 eV was generated in a gold cavity heated by
four laser beams on the SG-II laser system and was used to irradiate
a plastic foam cylinder at one end. The radiatively ablated foam
cylinder was then backlighted side-on by x-ray from a
laser-irradiated Ti disk. By observing the transmission decrease due
to the shock compression of the foam cylinder, the trajectories of shock
front were measured, and from the onset of the intense thermal
emission from the side of the cylinder, the propagations of
the ionization front were also observed on the same shot. The
experimental measurements were compared to predictions of the
radiation hydrodynamics code Multi-1D and reasonable agreements were
found. 相似文献
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A two-pulse two-wave (Nd and CO2 lasers) scheme is proposed for irradiating a laser target, which ensures the highest factor of laser radiation conversion to the X-ray range (13.5 nm ± 1%). Analytic estimates are obtained for parameters of pulses and of the target made of Xe or Li. Numerical optimization is performed for X-ray emission from a spherical Xe target exposed to a CO2 laser pulse. The maximal factor of conversion of laser radiation to X rays is ~1%. Angular and spectral characteristics of X-ray radiation are obtained. The flux of fast Xe ions ejected from the target and damaging the Mo/Si coating of X-ray mirrors is estimated. 相似文献
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M. Hagedorn J. Kutzner G. Tsilimis H. Zacharias 《Applied physics. B, Lasers and optics》2003,77(1):49-57
Hard X-ray radiation is generated at 1-kHz repetition rate on metal targets using 30-fs sub-millijoule laser pulses. Spinning-disc targets of medium-Z (Ti, Cr, Fe, Ni, Cu, Zn and Mo) and high-Z (Ta) metals are investigated. For medium-Z targets, characteristic K-shell emission (K and K) is observed in the 4–20 keV energy range in addition to a broadband bremsstrahlung background. Whereas in former studies similar results have been obtained by applying laser pulses in the tens-to-hundreds-of-millijoules range, we observe characteristic X-ray generation even at applied pulse energies as low as 100 J. The well-defined emission wavelength, the high intensity and the high brightness of this radiation makes this source a promising tool for time-resolved experiments with high-repetition-rate (10 kHz) small-scale table-top laser systems . PACS 42.65.-k; 52.38.Ph; 52.50.Jm 相似文献
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X-ray radiation of relativistic electrons interacting with a set of parallel atomic planes is considered. The anomalous behavior of the radiation due to the interplay of parametric and coherent bremsstrahlung emission mechanisms, which simultaneously occur under specific conditions, is studied. 相似文献
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黄庆举 《光谱学与光谱分析》2008,28(2):278-281
通过时间分辨的光谱测量技术,测定了308 nm XeCl紫外激光烧蚀金属Cu在氮气环境中诱导产生等离子体的发射光谱及其强度随时间分布,实验结果表明等离子体辐射光谱线主要由原子光谱线、一价离子光谱线及连续辐射背景光组成,各种光谱线的数目、辐射强度、持续时间不同。结合实验结果对等离子辐射机理进行了探讨,认为电子通过逆韧致辐射获得较高的能量,连续辐射主要来自高能电子的韧致辐射,原子和一价离子的激发主要是通过电子与原子、离子的碰撞传能以及电子与离子的复合产生,并用其定性地解释了所观察的实验现象。 相似文献
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We study spontaneous bremsstrahlung emission in a highly intense laser field. In this regime the interaction with the laser field has to be treated nonperturbatively by using the relativistic formalism including Dirac-Volkov propagators, while the interaction with the Coulomb field and the bremsstrahlung radiation can be treated in first-order perturbation theory. For the intermediate electron state a fully laser-dressed propagator is used, including radiative corrections to avoid singularities on the mass shell. We find that the use of the Dirac-Volkov propagator is crucial to obtain correct numerical results. The cross section of the process is evaluated for laser intensities of order 10(20) W/cm(2) and relativistic energies of the initial electron. 相似文献
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《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2009,37(11):2146-2152
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Effective-range theory is developed to describe the processes of multiphoton bremsstrahlung absorption and the emission of laser radiation that accompanies the scattering of electrons from atoms in a laser field. It is found that the cross sections for multiphoton absorption in the plateau region increases resonantly for electron energies corresponding to the thresholds of induced bremsstrahlung (i.e., multiples of the photon energy). It is shown that this effect is caused by the laser-field modified threshold phenomena in the cross sections for multichannel reactions (Baz’ threshold anomalies). 相似文献
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An ionizing radiation hazard produced from the interaction between high intensity lasers and solid targets has been observed. Laser-plasma interactions create "hot" electrons, which generate bremsstrahlung X-rays when they interact with ions in the target. However, up to now only limited studies have been conducted on this laser-induced radiological protection issue. In this paper, the physical process and characteristics of the interaction between high intensity lasers and solid targets are analyzed. The parameters of the radiation sources are discussed, including the energy conversion efficiency from laser to hot electrons, hot electron energy spectrum and electron temperature, and the bremsstrahlung X-ray energy spectrum produced by hot electrons. Based on this information, the X-ray dose generated with high-Z targets for laser intensities between 1014 and 1020 W/cm2 is estimated. The shielding effects of common shielding items such as the glass view port, aluminum chamber wall and concrete wall are also studied using the FLUKA Monte Carlo code. This study provides a reference for the dose estimation and the shielding design of high intensity laser facilities. 相似文献