为了解决防离子反馈Al2O3膜污染对三代微光管GaAs光电阴极灵敏度的影响, 用四级质谱计对制管超高真空室残气、无膜微通道板(MCP)和带Al2O3膜MCP在电子轰击时的放气成份进行分析。结果表明, 带Al2O3膜MCP放出有对阴极光电发射有害的C、CO、CO2、NO、H2O2和CXHY化合物, 它们来源于Al2O3膜制备过程的质量污染。经过对制膜工艺质量进行改进, 制备出了放气量小于2×10-9 Pa且无CXHY化合物气体的Al2O3膜。

In order to resolve the pollution effects of ion barrier Al2O3 film on GaAs photocathode sensitivity of third-generation low-light-level(LLL) tube,we used the quadrupole mass spectrometer to analyze the gas composition released from the ultra-high vacuum chamber,the microchannel plate(MCP) without film and the MCP with Al2O3 film under electron bombardment. The results show that the MCP with Al2O3 film releases the residual gases of C, CO, CO2, NO, H2O2 and CXHY, which come from the quality pollution during the preparation process of Al2O3 film .After improving the filming technology, we obtained the Al2O3 film with outgasing amount less than 2×10-9 Pa and without CXHY.