Author Affiliations
Abstract
1 State Key Laboratory of Nuclear Physics and Technology, Center for Applied Physics and Technology, School of Physics, Peking University, Beijing100871, China
2 Beijing Laser Acceleration Innovation Center, Beijing101400, China
3 Institute of Guangdong Laser Plasma Technology, Guangzhou510540, China
Carbon nanotube foams (CNFs) have been successfully used as near-critical-density targets in the laser-driven acceleration of high-energy ions and electrons. Here we report the recent advances in the fabrication technique of such targets. With the further developed floating catalyst chemical vapor deposition (FCCVD) method, large-area ($>25\kern0.5em {\mathrm{cm}}^2$) and highly uniform CNFs are successfully deposited on nanometer-thin metal or plastic foils as double-layer targets. The density and thickness of the CNF can be controlled in the range of $1{-}13\kern0.5em \mathrm{mg}/{\mathrm{cm}}^3$ and $10{-}200\kern0.5em \mu \mathrm{m}$, respectively, by varying the synthesis parameters. The dependence of the target properties on the synthesis parameters and the details of the target characterization methods are presented for the first time.
carbon nanotube foams laser-driven acceleration near-critical density targets ultraintense laser High Power Laser Science and Engineering
2021, 9(2): 02000e29
中国工程物理研究院 激光聚变研究中心, 等离子体物理重点实验室, 四川 绵阳 621900
基于激光驱动超热电子产生的高品质X射线源是高能量密度实验中有效的诊断技术手段, 对辐射源亮度、穿透性和时空分辨率等特性具有极高的要求。结合粒子模拟和蒙特卡罗模拟研究, 首先利用近临界密度等离子体实现了激光自聚焦通道中的大电量高能电子加速, 通过直接加速机制产生了电量超过600 nC、有效温度可达15 MeV的高能电子; 以此为基础提高电子-光子能量转换率, 有效优化了光子能量和产额, 并通过一定的转换靶参数优化方案产生了微焦点(FWHM小于200 μm)、高能、高亮度X射线, 为高空间分辨(小于200 μm)成像诊断提供了很好的途径, 有望早日实现激光等离子体轫致辐射单脉冲瞬态照相的实际应用。
激光 近临界 大电量 高能X射线 微焦点 laser near-critical high-charge high-energy X-ray micro spot 强激光与粒子束
2017, 29(8): 082003
Author Affiliations
Abstract
1 Department of Physics, University of Texas, Austin, TX, 78712, USA
2 State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, 100871, China
3 Fakultat fur Physik, Ludwig-Maximilians-University, Munich, Germany
The irradiation of few-nm-thick targets by a finite-contrast high-intensity short-pulse laser results in a strong pre-expansion of these targets at the arrival time of the main pulse. The targets decompress to near and lower than critical densities with plasmas extending over few micrometers, i.e. multiple wavelengths. The interaction of the main pulse with such a highly localized but inhomogeneous target leads to the generation of a short channel and further self-focusing of the laser beam. Experiments at the Glass Hybrid OPCPA Scaled Test-bed (GHOST) laser system at University of Texas, Austin using such targets measured non-Maxwellian, peaked electron distribution with large bunch charge and high electron density in the laser propagation direction. These results are reproduced in 2D PIC simulations using the EPOCH code, identifying direct laser acceleration (DLA) <参考文献原文>as the responsible mechanism. This is the first time that DLA has been observed to produce peaked spectra as opposed to broad, Maxwellian spectra observed in earlier experiments <参考文献原文>This high-density electrons have potential applications as injector beams for a further wakefield acceleration stage as well as for pump-probe applications.
Direct laser acceleration Electron acceleration Near critical plasmas PIC simulations Matter and Radiation at Extremes
2016, 1(1): 82
