Design of wall current monitor for proton accelerators

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.