共查询到20条相似文献,搜索用时 500 毫秒
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WANG Xiaofang XU Zhizhan ZHANG Zhengquan FAN Pinzhong LI Ruxin HAN Shengsheng LU Peixiang FENG XianpingZHANG Linqing SONG Xiangyang SHEN Baifei Xiang Huizhu 《Chinese Journal of Lasers》1995,4(4):319-322
ComparativeExperimentsonXUVEmissionsfromGrooveandPlanarTarget¥WANGXiaofang;XUZhizhan;ZHANGZhengquan;FANPinzhong;LIRuxin;HANSh... 相似文献
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透射光栅时间分辨谱仪 总被引:4,自引:1,他引:3
透射光栅时间分辨谱仪是获取激光等离子体软X光辐射高分辨能谱时间二维信息的实验诊断装置。介绍了在国内首次建立的透射光栅时间分辨谱仪的原理、结构和性能,给出了该谱仪测得的金平面靶软X光辐射能谱时间谱并对其做了初步的讨论。 相似文献
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讨论了利用激光等离子体产生水窗波段X光辐射的可能途径。靶材,即原子序数的选取是决定产生这一波段辐射的基本因素,利用激光等离子体的平衡态和非平衡态特性都可在水窗波段产生亮度X光辐射,提出利用黑体辐射来实现水窗波段X光显微成像研究的方案。 相似文献
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Summary Soft-X-ray generation in aluminium plasmas produced by Nd nano-second laser pulses is investigated analysing time-resolved
spectra ofK-shell line emission. Time histories of line emission and electron temperature as well as the time-integrated X-ray yield
were studied as a function of laser pulse duration and target position along the laser beam propagation axis. The experimental
results suggest that X-ray emission is influenced by self-focusing of laser light in the plasma.
Presently at Laboratoire pour l'Utilisations des Lasers Intenses, Ecole Polytechnique, 91128 Palaiseau Cedex, France. 相似文献
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V K Senecha Y B S R Prasad M P Kamath A S Joshi G S Solanki A P Kulkarni S Gupta R Pareek H C Pant 《Pramana》2000,55(5-6):789-795
An investigation of x-ray emission from Cu plasma produced by 1.054 μm Nd:glass laser pulses of 5 ns duration, at 2 × 1012 − 2 × 1013 W cm−2 is reported. The x-ray emission has been studied as a function of target position with respect to the laser beam focus position.
It has been observed that x-ray emissions from ns duration plasma show a volume effect similar to subnanosecond plasmas. Due
to this effect the x-ray yield increases when target is moved away relative to the best focal plane of the laser beam. This
result supports the theoretical model of Tallents and has also been testified independently using suitably modified theoretical
model for our experimental conditions. While above result is in good agreement with similar experimental results obtained
for sub-nanosecond laser produced plasmas, it differs from result claiming filamentation rather than pure geometrical effect
leading to x-ray enhancement for ns plasmas. 相似文献
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Sailaja S. Naik P.A. Gupta P.D. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2001,29(6):960-964
Quantitative measurement of spectral distribution of soft X-ray emission from laser produced plasmas and estimation of X-ray conversion efficiency are reported. The X-ray emission from planar gold target irradiated by an Nd:glass laser was recorded using a high resolution transmission grating spectrograph. Spectral distribution of X-ray intensity was derived using calibrated film data and a deconvolution procedure to account for contribution of higher diffraction orders. Results of conversion efficiency per unit solid angle, at a laser intensity of ~4×1012 W/cm2 (λL = 1.054 μm), for 10< λ <80 Å and in the water window spectral region (23< λ< 44 Å) are presented. A three-fold increase in conversion efficiency was observed for second harmonic laser irradiation (λL = 0.527 μm) at an intensity of 8×1012 W/cm2 相似文献
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Spatially and temporally resolved emission spectroscopy is used to study the major features of the onset and evolution of
plasmas created by pulsed laser irradiation of targets immersed in liquids. It is shown that double pulse operation provides
an enhanced rate of nanoparticle formation and increases the emission signal from the plasma atoms and ions owing to more
efficient ablation of the target material. The main parameters (density of atoms, electron temperature and density) of laser-induced
plasmas in liquids are estimated. The prospects of laser ablation in liquids as a method for producing nanoparticles are analyzed. 相似文献
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激光等离子体喷射空间特性实验观测 总被引:1,自引:1,他引:0
用1.053μm的高功率激光辐照不同类型的柱形腔靶,采用空间成像技术分别获取激光注入孔、腔内和输运口等离子体喷射空间分辨图像,对激光等离子体喷射空间特性进行了实验观测。还采用了平面靶和特殊构形的转换体靶观测等离子体喷射行为。本文给出了实验中获得的典型结果,并对这些结果进行了简要的分析讨论。 相似文献
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激光等离子体软X射线辐射能谱时间分辨测量研究 总被引:1,自引:1,他引:0
利用(国内最近研制成功的)带聚酰亚胺膜底衬的金透射光栅与软X射线条纹相机相配合,(在LF11~#激光装置上)使用波长为0.53μm的激光打靶,测量了平面Au靶软X射线时间分辨能谱。测量结果观察到了金等离子体的O带辐射强度随时间增加的现象。文章计算了光栅的衍射效率,并讨论了影响测量谱的几个关键因素。 相似文献
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利用神光-Ⅲ原型激光装置实验研究了8束ns激光脉冲从一端注入钛空腔靶产生的keV X射线源的辐射特征,发现keV X射线主要产生于腔轴附近;钛空腔靶内径过大时keV X射线能流的峰值强度较低,内径过小时keV X射线能流的持续时间较短。为了在4空间内使钛空腔靶获得最大的X射线(4~7 keV能段)转换效率,腔内径的最优值在1000~1300 m附近,此时的keV X射线转换效率为4.7%,是相同激光参数下钛平面靶的2倍左右。激光单端注入有底部钛膜和无底部钛膜的空腔靶对比实验显示,底膜能够增强keV X射线的发射。 相似文献
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利用神光Ⅱ第九路2 ns长脉冲激光束作用厚钛固体靶,研究了产生的keV X射线源的辐射区域和总辐射功率的时间行为。结果表明:在长脉冲激光作用厚固体靶时,硬X射线线辐射功率的时间行为以及辐射体积的时间行为与激光脉冲波形一致;长脉冲时,等离子体2维膨胀效应非常显著,keV X射线线辐射的径向辐射区域在激光焦斑尺寸附近达到饱和,导致X射线线辐射功率出现饱和,且keV X射线线辐射的辐射体积正比于焦斑尺寸的3次方。从理论和实验角度研究了在同样入射激光能量下,辐射功率随激光焦斑尺寸的变化关系,发现keV X射线线辐射的饱和辐射功率正比于焦斑尺寸的5/3次方,理论结果与实验结果一致。并讨论了相同基频输出激光能量下,keV X射线辐射总功率随激光波长的变化关系,发现即使考虑了倍频效率的影响,短波长激光仍然有利于keV X射线的发射。 相似文献
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Zhnhan XU Zhengquan ZHANG Pinzhong FAN Shisheng OHEN Peixiang LU Xiaofang WANG Saifei HEN Lihuang LINShanghai Institute of Optics Fine Mechanics Academia Sinica P.O. Box - Shanghai China 《Chinese Journal of Lasers》1992,1(1):1-7
Experimental studies of soft X-ray laser for the sodium-likerecombination scheme conducted at the LF12 Laser Facility of SIOM(Shanghai Instituteof Optics and Fine Mechanics)are reported.Soft X-ray amplification was observed insodium-like copper ions by line-focused laser irradiation of slab targets.Based on thespatially-resolved measurements,the spatial distribution of the laser gain for the transition6g—4f(72.22(?))of sodium-like copper ions was obtained,and the maximums of gaincoefflcients and gain-length products at 550μm from target surface were 2.0 cm~(-1) and 3. 6,respectively.The evolution of spectrally discriminated spatial uniformity of line-shapedplasmas as lasing gain media produced by uniform laser illumination in line-focus isalso investigated.It is found that under this experimental condition the line-shapedplasma is very uniform after laser heating. 相似文献
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微波辅助激光诱导击穿光谱增强大米中Cd发射强度的研究 总被引:1,自引:0,他引:1
食品安全问题已成为全世界关注的焦点,对食品中污染物的绿色检测方法有利于环境的可持续发展。以大米中重金属污染物Cd元素为研究对象,分别采用激光诱导击穿光谱(LIBS)和微波辅助激光诱导击穿光谱(MA-LIBS)对空白和实验室污染处理的大米样品进行检测,并选用Cd Ⅰ 228.802 nm为分析线,探讨目标元素分析谱线等离子体发射强度的增强效果。同时,采用阳极溶出伏安法获取大米中Cd元素的真实含量。研究结果表明,对于实验室配制的浓度范围在2.16~13.69 μg·g-1的大米样品,LIBS仅能检测出其中大米Cd真实含量为13.69 μg·g-1的样品;而在同一实验条件下,MA-LIBS能检测出所有污染后样品中的Cd元素信号,并且与LIBS方法相比,Cd元素谱线发射强度增强了9~27倍,检测灵敏度提高了6.34倍。结果表明,采用MA-LIBS能有效地增强大米中Cd元素等离子体的发射强度并提高其检测灵敏度。 相似文献
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在星光和神光激光装置上,用空间-时间分辨、能量-时间分辨技术,激光探针光技术以及法拉第电荷收集器,研究了平面金靶、玻璃球靶、黑洞腔靶的激光等离子体膨胀过程以及离子发射速度分布。观察到了球靶的球体与支撑杆之间以及激光未照射区的等离子体喷流结构。获得了金柱腔靶在特定功率密度下的解体时间。 相似文献
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激光辐照凹形靶提高激发态离子的丰度 总被引:2,自引:1,他引:1
本文通过分析比较激光辐照平面和凹形结构靶实验产生的等离子体辐射特性,发现在凹形靶的凹域中存在着丰富的高激发态离子并发射强的激光等离子体X射线. 相似文献