基于162.5 MHz HWR超导腔的氦压调谐器的设计与测试

Design and test of the helium pneumatic tuner based on 162.5 MHz superconducting cavity

162.5 MHz(?=0.10)半波长谐振型(Half Wave Resonance,HWR)超导腔被用于CIADS(China Initiative Accelerator Driven System)项目注入器II的低能段。氦气压力驱动式调谐器基于上述腔体的调谐范围及机械性能要求进行设计制造。为确保调谐器运行良好,进行了常温测试。铜制模型腔测试中调谐范围达到640 k Hz,满足频率调节范围要求。铌腔测试中得到腔体频率与气体压力关系,调谐敏感度为0.272 k Hz·h Pa-1。采用气体质量流量控制方案并搭建气体驱动控制平台进行分辨率测试,在测试结果显示调谐器满足调谐分辨率要求,分辨率精度达到4.4–15 Hz。计算了超导腔与调谐器间的传热量,其值不超过0.002 W,小于低温恒温器与调谐器之间的热辐射量,表明此调谐器可用于HWR腔体。

Background： 162.5 MHz （-=0.10） Half Wave Resonance （HWR） superconducting cavity is used for the low-energy section of injection II in the China Initiative Accelerator Driven System （CIADS） project. Purpose： The helium pneumatic tuner is designed on the tuning range and performance requirements of the mentioned cavity above. There is no domestic reference. Methods： In order to make sure that it would run well, room temperature test was made. Results： In the test of copper modal cavity, the tuning range reached 640 kHz, which satisfied the tuning range requirements. In the test of Niobium cavity, the connection of the frequency with the gas pressure was satisfied, the tuning sensitivity was 0.272 kHz-hPa-1. Gas mass flow control scheme was put forward. And a pneumatic platform for resolution test was set up. In the test, the tuner met the requirement of the tuning resolution, of which the resolution precision reached 4.4–15 Hz. The heat transfer between superconducting cavity and the tuner was calculated, and its value was no more than 0.002 W, which was lower than the thermal radiation between the cryostat and the tuner. Conclusion： The tuner could be used for HWR cavity.