HIAF随机冷却系统slot-ring型pickup/kicker及相应合路器/功分器的设计与仿真

为降低束流发射度，提高束流强度，得到高品质的束流，强流重离子加速器装置(HIAF)高精度环形谱仪(SRing)将建造随机冷却系统。随机冷却系统的关键硬件pickup/kicker在一定程度上决定了其冷却效率。本工作讨论了随机冷却系统pickup/kicker的具体作用及设计指标，介绍了分路阻抗概念。SRing随机冷却系统采用周期性单元结构slot-ring模型，利用高频结构仿真(HFSS)软件对其进行建模并仿真优化。通过对不同结构参数进行扫参，确认了slot-ring结构各参数对pickup/kicker分路阻抗值的影响。仿真结果表明，slot-ring结构有较高的分路阻抗，适用于SRing随机冷却系统。同时，考虑到pickup/kicker工作带宽内分路阻抗的平坦度，提出了采用不同尺寸slot-ring结构进行组合的方式来优化其平坦度。最后设计并加工实测了该slot-ring结构相匹配的十六路功率分配器/功率合成器，实测结果表明:该功分器/合路器具有各端口输出幅度平坦度较好、隔离度大、插入损耗低、电压驻波比小等特点，满足SRing随机冷却系统的要求。

Design and Simulation of Slot-ring Type Pickup/Kicker and Power Combiner/Splitter for HIAF Stochastic Cooling System

In order to reduce beam emittance, improve beam intensity and obtain high quality beam, a stochastic cooling system will be constructed for the high-precision Spectrometer Ring(SRing) in the High-Intensity heavy ion Accelerator Facility(HIAF). The pickup/kicker plays a significant role in the stochastic cooling system and determines its cooling efficiency to a certain extent. The paper discusses the significant function and design specification of the pickup/kicker of the stochastic cooling system, and introduces the concept of shunt impedance. The periodic element slot-ring structure is adopted for the SRing stochastic cooling system, and high frequency structure simulation software(HFSS) is used for modeling and simulation optimization. The effect of slot-ring parameters on shunt impedance of pickup/kicker is studied by sweeping different structural parameters. The simulation results show that the slot-ring structure has high shunt impedance and is suitable for SRing stochastic cooling system. At the same time, considering the flatness of the shunt impedance in the whole operating bandwidth of pickup/kicker, a combination of slot-ring structures of different sizes is proposed to optimize its amplitude flatness. Furthermore, a 16-way power splitter/combiner for the slot-ring structure is designed and fabricated. The measured results show that the combiner/splitter has the performance of a good output amplitude flatness, large isolation, low insertion loss, low voltage standing wave ratio and so on, which meets the requirements of the stochastic cooling system.