基于加速器的硼中子俘获治疗装置的需求与建设，对RFQ加速器的流强和占空比提出了更高的要求。在BNCT装置运行过程中加速器长时间正常稳定运行至关重要。对于RFQ加速器，则是要保证在运行过程中腔体内的谐振频率稳定和工作模式场分布稳定。为保证运行过程中谐振频率的稳定，最有效的方法是通过冷却循环水调谐的方法实现。本项目拟基于四翼型变电压RFQ加速器，在强流及高占空比工作条件下，使用ANSYS进行包括电磁场、流体、温度和结构的整腔三维多物理耦合计算，对RFQ腔体开展水冷物理分析与优化设计，以满足RFQ加速器在不同占空比或馈入功率条件下谐振频率稳定在要求范围内。在清华大学已建成的3MeV RFQ加速器基础上，建设和完善水冷调谐实验平台，通过调谐实验验证整腔三维多物理耦合分析方法。该分析和设计方法预期能对强流高占空比的四翼型RFQ加速器（不限于变电压设计）的成功建造提供技术支持，具有重要的工程应用价值。

Higher requirement on the peak current and duty factor of the RFQ accelerator is needed for the construction of the accelerator-based Boron Neutron Capture Therapy facility. During operation the long-term stable operation of the accelerator is very important. For the RFQ accelerator the resonance frequency and the field distribution inside the cavity shall be stable. The most effective method to stabilize the resonance frequency during operation is to tune the cavity with the cooling water system. In this project, based on the four vane RFQ with ramped inter-vane voltage, 3D couple field analysis of the whole cavity including the electromagnetic field, fluid, temperature and structure is carried out under high current and duty factor condition. The water-cooling physical analysis and design is planned to meet the requirement of the frequency stabilization with different duty factor or peak power. One water-cooling tuning experiment platform is planned to be constructed on the 3 MeV RFQ at Tsinghua university to verify the method of the 3D couple field analysis of the whole cavity. The analysis and design method is expected to provide the technical support of the construction of the four vane RFQ (not limited to the design with the ramped inter-vane voltage) under high current and duty factor condition, and shall be valuable to engineering application.