摘要
行星岩石成分原位测量是行星探测的基本需求,X射线荧光分析是开展元素成分测量的重要技术手段。针对深空探测X射线荧光分析仪的需要,设计并研制了一款微型微焦斑X射线闭管,尺寸为Φ15 mm×22 mm,焦斑尺寸230μm,工作时阳极接地,阴极接浮地负高压,最大电压为-50 kV。在微型X射线闭管研制过程中,开展了螺旋型钨丝、直线型钨丝、直线型铼钨丝等常用热阴极的电子发射差异性研究,测量了各型热阴极的电子发射效率。结果显示,在200 V阳极电压下,低铼含量直线型铼钨丝电子发射效率最大为27.87μA·W^(-1),是螺旋型钨丝的4倍,直线型钨丝的9倍;掺铼钨丝电子发射效率远高于纯钨型阴极丝。此外,铼钨丝还具有电子发射快、预热要求低、对真空度要求不高等特点,是深空探测X射线闭管阴极丝较理想的选择。
In-situ measurement of planetary rock composition is the basic requirement of planetary exploration, and X-ray fluorescence analysis is an important technical means to carry out elemental composition measurement. In order to meet the needs of X-ray fluorescence analyzer for deep space detection, a miniature X-ray closed tube with micro-focal spot is designed and developed. It size is Φ15 mm×22 mm,and the focal spot size is 230 μm. The anode is grounded in operation, and the cathode is connected to the floating negative high voltage with the maximum voltage of -50 kV. In this paper, the differences of electron emission of common hot cathodes such as spiral tungsten, linear tungsten and linear rhenium tungsten hot cathodes, are studied in detail, and the electron emission efficiency of each hot cathode is measured. The test results show that the maximum electron emission efficiency of linear rhenium tungsten wire is 27.87 μA·W^(-1)at 200 V anode voltage, which is 4 times that of spiral tungsten wire and 9 times that of linear tungsten wire. In addition, rhenium tungsten wire has the characteristics of fast electron emission, low preheating requirement and low vacuum requirement, so it is an ideal choice for X-ray closed tube cathode wire for deep space exploration.
作者
李帆
曹阳
牟欢
刘亚宁
李海涛
李保权
LI Fan;CAO Yang;MOU Huan;LIU Yaning;LI Haitao;LI Baoquan(National Space Science Center,Chinese Academy of Sciences,Beijing 100190;University of Chinese Academy of Sciences,Beijing 100049)
出处
《空间科学学报》
CAS
CSCD
北大核心
2023年第1期137-143,共7页
Chinese Journal of Space Science
基金
国家重点研发计划项目(2017 YFB0503300)
国家自然科学基金项目(41604152,U1938111)
中国科学院青年创新促进会项目(2018178)共同资助。
关键词
微型X射线闭管
X射线荧光分析
微焦斑
阴极丝
电子发射效率
Micro X-ray closed tube
X-ray fluorescence analysis
Micro focal spot
Cathode filament
Electron emission efficiency