Development of bunching system for high intensity cyclotron at CIAE

A new double-gap buncher is designed for the CYCIAE-10 cyclotron in order to get the high-intensity proton beam with the order of mA. RF simulation is carefully performed to achieve a deep quantitative analysis of the equivalent capacitance and electrical field distribution. Uniform electrical field technology is verified by EM field simulation to get an electrical field uniformity of 94.67%. Type L matching circuit is used to transfer the loading reactance to 50 Ohms. Variable vacuum capacitor with 5-50 pF is selected for its small power loss and the convenience of commissioning. Dynamic calculation of the buncher and mechanical design are also presented in this paper. The open-loop bench test shows that 370 V_peak RF voltage is established in the central electrode with power consumption of 37 W. Alternative redesign and online test are carried out, and more than 1 mA H^- beams are achieved on the inner target, which verify the buncher design. (author)