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A deuterium cluster jet produced in the supersonic expansion into vacuum of deuterium gas at liquid nitrogen temperature and moderate backing pressures are studied by Rayleigh scattering techniques. The experimental results show that deuterium clusters can be created at moderate gas backing pressures ranging from 8 to 23 bar, and a maximum average cluster size of 350 atoms per cluster is estimated. The temporal evolution of the cluster jet generated at the backing pressure of 20 bar demonstrates a two-plateau structure. The possible mechanism responsible for this structure is discussed. The former plateau with higher average atom and cluster densities is more suitable for the general laser-cluster interaction experiments. 相似文献
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利用平场光栅谱仪,分别在2和3 kPa的低气压下,测量了脉宽35 fs的圆偏振超强超短激光脉冲与5 mm长氙气体靶相互作用产生的波长在5~60 nm范围内的离子谱线.2kPa时最强的跃迁为XeⅧ:4dd105s(2S1/2)-4d95s5p(2P3/2)的17.085 6nm线,3kPa时最强的跃迁为11.343mm的XeⅦ4d105s2(1S0)-4d95s25f(3P1)跃迁.两种气压下,Xe均被电离到XeⅦ,XeⅧ,XeⅨ态. 相似文献
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Self-Injection and Acceleration of Monoenergetic Electron Beams from Laser Wakefield Accelerators in a Highly Relativistic Regime 下载免费PDF全文
H.Yoshitama ;T.Kameshima ;谷渝秋 ;郭仪 ;焦春晔 ;刘红杰 ;彭翰生 ;唐传铭 ;王小东 ;温贤伦 ;温天舒 ;吴玉迟 ;张保汉 ;朱启华 ;黄晓军 ;安维民 ;黄文会 ;唐传祥 ;林郁正 ;王小东 ;陈黎明 ;H.Kotaki ;M.Kando ;K.Nakajima 《中国物理快报》2008,25(8):2938-2941
Self-injection and acceleration of monoenergetic electron beams from laser wakefield accelerators are first investigated in the highly relativistic regime, using 100 TW class, 27 fs laser pulses. Quasi-monoenergetic multi- bunched beams with energies as high as multi-hundredMeV are observed with simultaneous measurements of side-scattering emissions that indicate the formation of self-channelfing and self-injection of electrons into a plasma wake, referred to as a 'bubble'. The three-dimensional particle-in-cell simulations confirmed multiple self-injection of electron bunches into the bubble and their beam acceleration with gradient of 1.5 GeV/cm. 相似文献
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We demonstrated the interaction of a gold cone target with a femto second(fs) laser pulse above the relativistic intensity of 1.37×10 18 μm 2 W/cm 2.Relativistic electrons with energy above 2 MeV were observed.A 25%-40% increase of the electron temperature is achieved compared to the case when a plane gold target is used.The electron temperature increase results from the guiding of the laser beam at the tip and the intense quasistatic magnetic field in the cone geometry.The behavior of the relativistic electrons is verified in our 2D-PIC simulations. 相似文献
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对三台单光子计数CCD的能量响应特性和探测效率进行实验标定。采用标准放射源对CCD进行照射,将CCD图像进行统计处理后,得到CCD的能量响应曲线。响应曲线近似为线性,不同的CCD响应曲线斜率明显不同。编写了MATLAB程序对多像素事件进行处理,获得CCD的探测效率曲线。在不同的能点处,CCD的探测效率明显不同,在5.1keV附近探测效率达到最大值。标定结果与XOP软件计算得到的吸收效率理论结果比较一致。该标定结果可用于超强激光打靶产生的Kα荧光光子产额和能谱的定量精确处理。 相似文献
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超短超强激光与等离子体相互作用产生的激光尾波场可以在毫米尺度上加速产生高能量的准单能电子束.在SILEX-Ⅰ激光装置上进行的激光尾波场加速实验中,利用超强飞秒激光与超声速锥形喷嘴产生的2.7mm直径氦气气体柱相互作用,获得了能散为15.5%、发散角为15mrad、能量为58MeV的准单能电子束.在70TW激光照射下获得的电子束总电量达到15.4nC.介绍了实验条件、方法和主要实验结果. 相似文献
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A Princeton Instruments PI-LCX 1300 charge-coupled device (CCD) camera used for X-ray spectrum measurements in laser-plasma experiments is calibrated using three radioactive sources and investigated with the Monte Carlo code Geant4. The exposure level is controlled to make the CCD work in single photon counting mode. A summation algorithm for obtaining accurate X-ray spectra is developed to reconstruct the X-ray spectra, and the results show that the developed algorithm effectively reduces the low-energy tail caused by split pixel events. The obtained CCD energy response shows good linearity. The detection efficiency curves from both Monte Carlo simulations and the manufacturer agree well with the experimental results. This consistency demonstrates that event losses in charge collection processes are negligible when the developed summation algorithm of sDlit Dixel events is emDloved. 相似文献