基于光电阴极的超快X射线源设计及调制性能研究

Design and Modulation Performance of Ultrafast Light-controlled Pulsed X-ray Tube with Photocathode

为解决基于热阴极的传统X射线管灯丝发射结构脆弱、能量效率低以及散热等问题,设计了一种新型光控脉冲X射线管装置。通过光电阴极与光源的参数匹配,选择蓝光波段量子效率高的S20阴极与波长为460 nm的LED光源。模拟计算确定X射线管整体结构设计。最终实现最大2.37 mA的管电流,光电阴极电子发射效率为0.288 mA/lm,出射X射线能量0~25 keV可调。另外,基于光控脉冲X射线管出射X射线强度易调制的特性,进行不同频率加载信号还原实验和任意X射线轮廓还原实验。

In order to solve the easy-broken structure,low energy efficiency and heat dissipation of the traditional X-ray tube with filament based on thermionic cathode,a novel light-controlled pulsed X-ray tube device is deostrated in this paper.By matching the parameters of photocathode and light source,S20 cathode with high quantum efficiency and LED with 460 nm wavelength were selected.At the same time,the overall structure design of the X-ray tube is determined by the simulation.Finally,the maximum tube current of 2.37 mA is realized,the electron emission efficiency of photocathode is 0.288 mA/lm,and the output X-ray energy is adjustable from 0 to 25 keV.In addition,based on the characteristics of easy-access to be modulated of the light-controlled pulsed X-ray tube,different frequencies input signal restoration experiment and arbitrary contor X-ray restoration experiment was carried out.