为了掌握微通道板探测器的X射线脉冲信号观测能力, 利用X射线脉冲星地面实验装置, 开展了长时间的不同流强和不同背景噪声强度下的微通道板探测器脉冲信号探测实验, 并建立了一套X射线探测器脉冲观测能力评估方法, 推导出基于光子计时模式下X射线探测器的脉冲信号信噪比、脉冲轮廓相似度、脉冲到达时间精度和最小可探测功率的关系表达式.实验中, 利用面积20 cm2的微通道板探测器开展了8组10 000 s的实验, 采集到有效观测数据, 然后搜索最佳脉冲周期, 重构观测脉冲轮廓, 估计脉冲轮廓特征参数.实验表明, 微通道板探测器具备良好的X射线脉冲信号观测与恢复能力, 在较弱脉冲信号强度(光子流量密度为0.05 ph/cm2/s)和较强背景噪声(背景噪声强度是脉冲信号的16倍)下获取观测脉冲轮廓的信噪比、相似度、脉冲到达时间观测精度分别为35.73、88.38%、51.53 μs和64.89、89.72%、29.24 μs, 验证了微通道板探测器具备一定的暗弱X射线脉冲星观测能力, 且微通道板探测器的脉冲探测能力随着脉冲信号强度增加、背景噪声强度减弱、累积观测时间增加而提升.

For analyzing the X-ray pulsed signal observation capability of micro-channel plate detector, a long-time experiment of micro-channel plate detectors under different radiation flux and different background noise was operated on the X-ray detector ground testing system. Meanwhile, a set of evaluation methods of pulse observation capability of X-ray detectors were established, the expressions of the signal-to-noise ratio, the correlation of pulse profile, the measurement accuracy of pulse arrival time, the minimum detectable power were derived based on the photon counting model. 8 groups of 10 000 s X-ray photon time-of-arrival dataset were received by the 20 cm2 micro-channel plate detectors. Then the effective observation data were dealt with, the pulse period of each dataset was gained, the observable pulse profile was replicated, and their characteristic parameters were estimated. The experimental result shows that the micro-channel plate detector has a good capability of X-ray pulse signal observation and reconstruction, the signal-to-noise ratio, the correlation of pulse profile, the measurement accuracy of pulse arrival time of the observed pulse profile are 35.73, 88.38%, 51.53 μs at the low pulse signal flux (the X-photon flux density is 0.05 ph/cm2/s), while those are 35.73, 88.38%, 51.53 μs at strong background noise(the background noise is 16 times the intensity of the pulse signal). This result has revealed that the micro-channel plate detector has the observation ability of a certain faint X ray pulsar. The pulse detection capability of micro-channel plate detector is improved with the increase of the intensity of the pulse signal, the decrease of the background noise intensity and the increase of the accumulated observation time.