Carbon-fiber Discharge Plasmas as a Soft X-ray Source for Calibration

我们提出了碳纤维放电等离子体作为软x射线源校准探测器和光谱仪器。研究了两种在放电电极之间安装直径为7 <微> m的脆性碳纤维的方法。(1)在充水的放电室中，用一对微镊子将纤维从纤维夹中夹起。(2)一种装载系统，其带有包含所述纤维的筒体和能够将所述纤维安装在真空室中的真空密封装载器。将1毫米厚的圆盘状塑料闪烁体与光纤相结合，设计了一种紧凑、快速响应的x射线传感器。研究了碳纤维在三种环境条件下的放电特性。(1)在大气压下，冲击波起源于纤维表面并在周围空气中传播。放电电流流经两个区域，即光纤和空气的激波加热等离子体。(2)在水中，电流只在碳等离子体中流动。手掌的电导率由考虑退化状态的理论方程得到。(3)在真空中，纤维的一部分蒸发并达到等离子体状态。提出了一种用石墨插层材料放电碳纤维的可调x射线源。为了验证这个想法，x射线发射是在铜涂层碳纤维放电中测量的。

We proposed carbon-fiber discharge plasmas as a soft X-ray source for calibration of detectors and spectroscopic instruments. Two methods have been developed for installing brittle carbon-fiber of 7 <micro> m in diameter between discharge electrodes. (1) A pair of microtweezers is used to pick up the fiber from a fiber holder in a water-filled discharge chamber. (2) A loading system with a cartridge containing the fiber and a vacuum sealed loader enabled to install the fiber in a vacuum chamber. A compact and fast response X-ray sensor is devised by combining a 1 mm thick disc-shaped plastic scintillator and a optical fiber. Carbon-fiber discharge characteristics have been examined in three environmental conditions. (1) In atomospheric pressure, a shock wave originates at the surface of the fiber and propagates in the surrounding air. The discharge current flows through two regions, namely, the fiber and the shock heated plasma of the air. (2) In water, the current flows in the carbon plasma only. The electrical conductivity of the palsma is obtained by the theoretical equation considering degerated states. (3) In vacuum, a part of the fiber evaporates and comes to a plasma state. A tunable X-ray source is proposed by discharging the carbon-fiber with graphite intercalated materials. To examine this idea, X-ray emission is measured in a copper coated carbon-fiber discharge.