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GEM探测器的供电一般采用电阻链分压供电模式和多路分立供电模式,在低通量X射线下测量时区别不大,但是在高通量X射线时,电阻链分压供电模式会带来饱和效应引起工作电压的变化,造成探测器工作不稳定。本研究在高通量X射线照射下,研究了有效面积为100 mm×100 mm三层级联GEM探测器的有效增益(稳定性)与不同高压供电模式的关系。通过测量不同分压电阻值(1,2,5到30 M?)的实验研究,发现随着X射线通量的增加,在电阻链分压供电模式下,出现了GEM探测器感应电极的读出电流饱和趋势,分析了可能导致饱和效应出现的原因。结果表明,当入射X射线在探测器上的有效吸收剂量不断增加时,电阻链供电模式需要调整分压单元电阻值,或者采用多路分立供电模式,从而避免因饱和效应引起的GEM探测器有效增益的变化,实现探测器稳定的工作状态。
The power supply of GEM detectors generally adopts the power supply mode of resistor chain voltage division and the mode of multiple separate power supply, and the difference between them is not significant when measuring under low-flux X-ray. However, in high-flux X-ray, To saturation effect caused by changes in operating voltage, resulting in unstable detector. In this study, high-throughput X-ray irradiation, the effective area of 100 mm × 100 mm triple GEM detector effective gain (stability) and different high-voltage power supply mode. By measuring the different partial resistance (1, 2, 5 to 30 MΩ) experimental study found that with the increase of X-ray flux, in the resistive chain voltage division mode, there GEM sensor electrode The trend of current saturation is read out and the possible causes for the saturation effect are analyzed. The results show that when the effective absorbed dose of incident X-ray on the detector increases continuously, the resistive chain power supply mode needs to adjust the voltage divider unit resistance value or adopt the multi-path discrete power supply mode to avoid the GEM detector caused by the saturation effect Gain changes, to achieve a stable working state of the detector.