针对中国散裂中子源快同步环上束团纵向长度和束流强度的测量工作以及“973”束流损失控制实验课题中束团时间结构的测量工作，研制了用于上述两台质子加速器的壁电流探头。介绍了使探头达到足够的带宽所做的改进工作。用高频电磁场仿真软件对探头的性能进行了模拟，验证了适用于壁电流探头的一些理论模型和加入屏蔽腔对探头高频响应曲线产生的影响以及做出相应的改进后所带来的效果。对实物探头的性能进行了测量实验，发现测量系统自身的不匹配对实验结果产生了影响，改进匹配后得到探头的幅频响应曲线在300 kHz~2 GHz的频率范围内基本保持一致。时域上对500 ns脉冲矩形波的测量结果也显示出探头良好的低频响应。

A wall current monitor(WCM) was designed and built for measuring the bunch longitudinal length and beam intensity of the radio frequency quadrupole accelerator supported by “973 Program”. The design method will be used for the WCM of Rapid Cycling Synchrotron of China Spallation Neutron Source. A high frequency electromagnetic field simulation software was used to simulate the performance of WCM with ferrite rings and shielding cavity and corresponding improvements by using a microwave absorber to restrain cavity resonance. Test was done and the original result was affected by the test system. Finally the expected result was obtained by improving the impedance of the unmatched part of the test bench.