CAFe DUMP前刮束器的设计研制

位于中国科学院近代物理研究所的超导直线加速器样机CAFe是一台质子超导直线加速器实验样机，围绕该装置的束流实验研究将为下一步设计研究加速器驱动次临界洁净核能系统(ADS)专用的超导直线加速器打下基础并提供经验。为了实现CAFe的10 mA束流指标，需要设计研制专门的束流收集器(DUMP)和对应的刮束器。本工作就CAFe DUMP前刮束器的研制进行了系统的设计和计算工作。刮束器面向束流侧的材料采用Al6063，确保束流轰击后的剩余放射性活度处于安全范围。基于蒙特卡罗粒子输运模拟，开展放射性核素及剩余剂量分析。结果表明，退役时刮束器外围剂量为可接受的百微希沃特每小时量级。通过ANSYS的热分析，计算了不同束流情况下刮束器的温度分布及温度变化，研究了刮束器在正常运行时移除热量的能力和在异常状况下应急保护的能力。计算结果表明，刮束器可以满足安全移除强流高功率束流束晕的设计需求。在CAFe高功率束流实验中，刮束器及DUMP运行正常，束流监测指标与设计一致，证明研制的刮束器实现了安全移除束晕、监测束流参数和保护DUMP的功能。

Design and Development of the Collimator in Front of the CAFe DUMP

CAFe facility, located at Institute of Modern Physics, Chinese Academy of Sciences, is an experimental prototype of superconducting proton linac. The beam experiment research surrounding this facility can lay a foundation, and provide experience for the design and research of accelerator of Accelerator Driven Subcritical System(ADS) in the future. A special beam DUMP and a corresponding beam collimator before it are needed to achieve CAFe's 10-mA beam goal. In this paper, the systematic design and calculation of the beam collimator are carried out for the development of CAFe DUMP. To ensure that the residual radioactivity after beam bombardment is within a reasonable range, Material of Al6063 is used for the collimator inner element facing the beam. Based on Monte Carlo particle transport simulation, radionuclides and residual dose analysis were carried out. The results show that the peripheral dose of the collimator will be on the order of 100 μSv/h, which is acceptable during decommission. The temperature distribution and temperature raise of the collimator under various beam conditions are simulated with ANSYS code. It is demonstrated that the collimator can safely remove heat from beam power under normal conditions and protect the device under abnormal conditions effectively. The results show that the collimator meet the design requirements of beam halo removal. During the CAFe high power beam commissioning, the collimator and the DUMP were operated normally, with beam current monitoring value consistent with the designed parameters. It proved that the collimator realized the function of beam halo removal, beam parameters diagnostics and DUMP protection.