摘要
微通道板光子计数成像探测器是嫦娥三号极紫外相机的关键成像器件,嫦娥三号极紫外相机被用于探测地球等离子层中极微弱的He+共振散射辐射,为了消除微通道板内部吸附的残余气体产生的离子反馈等背景噪音对探测器微弱信号成像性能的影响,需要对微通道板进行预处理.预处理包括高温真空烘烤和紫外光电子清刷.根据预处理的实验要求,设计了一套微通道板预处理装置,为微通道板预处理实验提供高真空环境和高温加热及保温功能.本文详细介绍了微通道板预处理实验的实现过程,对三片Z型级联的微通道板进行预处理实验后,背景噪音由27.09counts/s·cm2降低为0.53counts/s·cm2、空间分辨率达到125μm,上述实验结果表明MCP在预处理之后其表面、亚表面和体内吸附的杂质气体得以有效去除,获得了稳定的增益,成像性能也得以改善.
A preconditioning process encompassed vacuum baking and burn-in with ultraviolet radiation.An equipment of preconditioning of microchannel plate was designed which could provide vacuum environment(10-5 Pa at least) as well as heating elements.The heating elements were controlled to reach 350℃ and then the vacuum chamber was sustained 350℃ for 18 hours in the procedure of bake-out.The burn-in procedure illuminating with ultraviolet radiation(253.7 nm) from a deuterium lamp was achieved when 0.06 Coulomb cm-2 was extracted from the MCP stack output.After the preconditioning the image spatial resolution reached to 125 μm,the background events rate dropped to be 0.53 counts/s·cm2 from 27.09 counts/s·cm2,the pluse height distribution curve closed to Gauss distribution and turned to be more narrow.
出处
《光子学报》
EI
CAS
CSCD
北大核心
2012年第6期658-663,共6页
Acta Photonica Sinica
基金
国家自然科学基金(No.61077016)资助
关键词
微通道板
预处理
脉冲高度分布
极紫外
Microchannel plate
Preconditioning
Pluse height distribution
Extreme ultraviolet
