射频超导腔前向功率耦合器的研制

Development of RF superconducting cavity forward power coupler

25 MeV超导直线加速器是中国加速器驱动次临界反应堆系统(China Initiative Accelerator DrivenSystem,CiADS)的一个预研装置,在该预研装置中,其核心加速部件超导腔的低温性能至关重要。前向功率耦合器是超导腔的重要组成部分。目前国内前向功率耦合器的机械结构大部分采用拉杆结构,其结构简单,低温下(4 K)能够稳定运行,但是空间利用率低,并且不具备普适性。针对25 MeV超导直线加速器多腔型的特点,设计开发了一种能够弥补传统耦合器不足的滑轮式前向功率耦合器,工程内应用结果表明:滑轮式前向功率耦合器结构简单,低温下运行稳定,空间利用率高,能满足工程内各种腔型测试要求。

[Background] The 25 MeV superconducting linac is a pre-research device of the China initiative accelerator driven system (CiADS), which includes a normal temperature front end, a superconducting acceleration section and a high-energy beam transmission line. The beam energy is 2.1 MeV at the normal-temperature front-end exit, and after the superconducting acceleration section, the proton beam is accelerated to 25 MeV. In this preexploration device, the superconducting cavity is the core accelerating component of the entire accelerator whilst the forward power coupler is an important part of it. So far, most of the design of forward power couplers in China adopt drawbar structure which has a simple structure and stable operation at low temperature (4 K), but the space utilization rate is low and not universal.[Purpose] This study aims to develop a new forward power coupler to replace the drawbar structure forward power couplers.[Methods] The characteristics of the multi-cavity type of 25 MeV superconducting linear accelerator was analyzed, a pulley-type forward power coupler structure with simple structure, and low temperature stability was designed and developed. The internal application of the project showed its high space utilization, suitability for various cavity types, and good universality.[Results] This type of forward power coupler has been used to test the cavities of 25 MeV superconducting linac. The test results show that the structure meets the engineering test requirements.[Conclusion] The pulley structure can be applied to different types of cavity.