2015 IMP & HIRFL Annual Report · 305 · The charging and discharging trigger signals for kickpower supplies are sent when the kicker control system receives the event code for beam extraction and the RF signal. The waveform of discharge for extraction captured by an oscilloscope is shown in Fig. 2. All delay times can be adjusted individually, and the digital delayer achieved a precision of 2.5 ns. A pre-trigger signal is provided to synchronize by the controller for the beam diagnostic system and physics experiments. Experimental results indicate that the phenomena of “missed kick” and “inefficient kick” were not observed, and the beam transport efficiency was improved compared to the original system. The Chinese “12th five-year plan” major project projects( The major of China’s 12 th five year plan)– HIAF(High Intensity Heavy-ion Accelerator Facility) will use Barrier Bucket longitudinal stacking to achieve high gain stacked high current heavy ion beam. For the HIAF pre-research project, a new controller is designed by our research group and the test experiment using the new controller is completed successfully to capture the two beam phases. We plan to have an experiment in-beam based on the new designed controller under the Barrier Bucket dual-ring mode and two-RF mode at the HIRFL in 2016. References [1] Wenxiong Zhou, Yanyu Wang, Detai Zhou, et al., Nuclear Instruments and Methods in Physics Research A, 728(2013)112. [2] Yanyu Wang, Wenxiong Zhou, Jinfu Luo, et al., Nuclear Instruments and Methods in Physics Research A, 738(2013)50. [3] D. T. Zhou, Y. Wang, Y. Li, et al., Nuclear Physics Review, 31(2014)48. (in chinese) 6 - 30 Design of the Tuning Capacitor with the DTL2 RF Cavity Tian Ruixia, Jin Peng and Fu Xin SSC-LINAC is as a linear injector for the cyclotron accelerator SSC. DTL2 RF cavity is designed to install in SSC-LINAC intermediate energy beam line, whose working frequency is 53.667 MHz and working mode is cw. DTL2 cavity adopts drift tube structure with IH-mode, which having high shunt impedance, high quality, etc. Tuning of DTL2 RF cavity is designed based on the perturbation [1] theory, which used to compensate frequency drift of cavity which caused by machining and manufacturing process, the temperature and other factors. The DTL2 RF cavity is designed with two tuning capacitors, a coarse tuning capacitor and a fine tuning capacitor. The coarse tuning capacitor is used to compensate the frequency error caused by the production and processing accuracy of the cavity, which regulating frequency range is 0∼1.0 MHz. The fine tuning capacitor is used for real time frequency tuning to coordinate Low Level Control System [2] in the actual operation of the cavity, which regulating frequency range is 0∼0.1MHz. The resonant frequency of the cavity could be adjusted with two tuning capacitor to make the cavity working on the resonance frequency point stability. This paper mainly elaborate the design of the coarse tuning capacitor. Fig. 1 (color online)The position of the coarse tuning capacitor in the cavity. According to the physical requirements of the cavity, the CST simulation model was established (see Fig.1) and the electromagnetic field distribution of the cavity could be obtained through simulating calculating. Depending on the electromagnetic field intensity of different area, the installation position of the coarse tuning capacitor could be determined, as shown in Fig. 2.