二次电子发射直接影响法拉第探测器测量质子束流的精度，减小或消除二次电子发射的影响是提高束流测量精度的关键。根据二次电子补偿原理设计了二次电子补偿型同轴法拉第探测器，实验发现探测器测量质子束流强度时不能完全实现二次电子补偿。为改进和完善探测器的设计，从理论上分析了补偿片未能完全消除二次电子对束流测量影响的原因，是由于补偿片前向发射二次电子数目大于收集极后向发射二次电子数目所致。为此设计了质子束穿过金属箔发射二次电子测量装置，测量得到能量为5~10 MeV质子穿过10 μm厚铜箔时前向与后向发射二次电子产额，验证了理论分析的正确性。

Accurate measurements of an intense high energy proton beam are generally disturbed by high energy proton induced secondary electron emission. In the present work, a compensation coaxial Faraday cup has been designed according to the compensation mechanism for secondary electron emission. The reason of the uncertainty for measuring proton beam intensity has been investigated. It is that the difference between the forward electron emission field and backward electron emission yield from compensation plate. The experiment is carried out at EN 2×6 accelerator in Peking University to measure the forward and backward electron emission yields from cupper foils penetrated by high energy proton in the energy ranging from 5 MeV to 10 MeV. The ratio of the forward electron emission yield to the backward electron emission yield is 1.3 as high energy proton penetrates a 10 μm thick cupper foil. The results are in excellent agreement with the simulation results.