Design Study of a Schottky Pickup Prototype Cavity for HIAF SRing

Schottky mass spectrometry serves as a powerful tool for studying radioactive decay and decay modes of highly charged ions. The spectrometer ring (SRing) of the high-intensity heavy-ion accelerator facility (HIAF) project plans to employ Schottky cavities for ion mass measurements and decay studies. However, existing cavities exhibit limited signal intensity under weak beam conditions, resulting in insufficient sensitivity. To address the high-resolution single-particle detection requirements of HIAF SRing, this study designed and developed a 1.14 GHz high-quality-factor (Q-factor) Schottky pickup resonant cavity prototype. Through CST simulation optimization, the unloaded Q-factor reached 12000. The prototype features a composite structure with a stainless steel cavity body and copper-plated inner surface, manufactured via precision machining and electron beam welding. Experimental tests confirmed the resonant frequency alignment with simulations, while the measured loaded Q-factor of 6000 revealed that copper plating conductivity was the primary cause of deviation.This research validates the cavity design feasibility, provides critical technical support for high-precision single-particle measurements in HIAF, and establishes a foundation for optimizing heavy-ion storage ring instrumentation.