• High Power Laser Science and Engineering
  • Vol. 9, Issue 2, 02000e29 (2021)
Pengjie Wang1, Guijun Qi1, Zhuo Pan1, Defeng Kong1, Yinren Shou1, Jianbo Liu1, Zhengxuan Cao1, Zhusong Mei1, Shirui Xu1, Zhipeng Liu1, Shiyou Chen1, Ying Gao1, Jiarui Zhao1, and Wenjun Ma1、2、3、*
Author Affiliations
  • 1State Key Laboratory of Nuclear Physics and Technology, Center for Applied Physics and Technology, School of Physics, Peking University, Beijing100871, China
  • 2Beijing Laser Acceleration Innovation Center, Beijing101400, China
  • 3Institute of Guangdong Laser Plasma Technology, Guangzhou510540, China
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    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.

    1 Introduction

    Ultra-intense laser interacting with plasma is a rapidly developing field attracting much attention. It has been demonstrated that multi-gigaelectronvolt electrons[1], approximately 100 MeV ions[24], and copious secondary radiations from extreme ultraviolet bursts[5,6] to gamma rays[7,8] can be generated from the complex interactions. In these studies, targets play the core roles as they determine the properties of the plasma. Many kinds of targets[9] have been employed in the experiments. Gas targets, generated from a supersonic nozzle[10] or contained in a cell, have been widely used for electron acceleration in laser wakefield acceleration scheme. Solid targets, in contrast, are widely employed for ion acceleration. Micrometer-thick metal or plastic foils were firstly used to accelerate protons in target normal sheath acceleration (TNSA)[11] scheme. Later on, other schemes such as radiation pressure acceleration (RPA)[12] and relativistic induced transparency (RIT)[13] were explored in experiments thanks to the successful fabrication of free-standing nanometer-thin foils made of diamond-like carbon (DLC)[14], plastic or metal foils[15,16].