The engineering design of quarter size negative beam source for the comprehensive research facility for fusion technology

A high-power radio frequency (RF) beam source is a key component for Negative Neutral Beam Injector (NNBI) in ASIPP. According to the technical route planning of CRAFT-NNBI beam source project, ASIPP started thedevelopment of quarter-size RF negative source and corresponding test facility. The inner diameter of the faradayshield (FS) of RF driver is 240 mm, the outer diameter of the accelerator is 1 m, with three-layer grids extractionsystem, which comprises the plasma grid (PG), extraction grid (EG) and ground grid (GG). The size of PG is512 mm × 396 mm × 9 mm, with two rows of 16 × 6 apertures made of pure molybdenum. The structure designof RF negative beam source and the manufacturing process of key components are presented, with emphasis onthe manufacturing process of FS as well as grids. Furthermore, the fluid-thermal-structural analysis of PG, themechanical analysis and material bonding strength test of the main insulation structure of beam source, as wellas the preliminary layout of the latest test facility are presented.

高功率射频（Radio Frequency，RF）束源是ASIPP负中性束注入器（Negative Neutral Beam Injector，NNBI）的核心组成部件。根据CRAFT-NNBI束源项目的技术路线规划，ASIPP启动了四分之一尺寸射频负源及其配套测试装置的研制工作。该射频驱动腔（RF driver）的法拉第屏蔽罩（Faraday Shield，FS）内径为240 mm，加速器外径达1 m，采用三层栅极引出系统，该系统包含等离子体栅（Plasma Grid，PG）、引出栅（Extraction Grid，EG）与接地栅（Ground Grid，GG）。等离子体栅尺寸为512 mm × 396 mm × 9 mm，设有两排共计16×6个纯钼材质的引出孔。本文阐述了射频负束源的结构设计方案与关键部件的制造工艺，重点聚焦于法拉第屏蔽罩及栅极的制造流程。此外，还涵盖了等离子体栅的流-热-结构耦合分析、束源主绝缘结构的力学分析与材料结合强度测试，以及最新测试装置的初步布局方案。