Double cup cover ion source filament seat structure for preventing metal spraying

Abstract

The invention relates to the technical field of ion sources, and particularly discloses a double cup cover ion source filament seat structure for preventing metal spraying. The structure adopts a simple double cup cover set shackle structure, and achieves the functional effect of insulation (tungsten filament spraying and plasma bombardment and the like) in bad working conditions by adding insulating parts as least as possible and size change at a position with limited space; an upper cover completely covers a rectangular block structure of a molybdenum rod, thus greatly reducing plasma bombardment which is easily suffered, fully utilizing the safety clearance between a lower cup cover and a ceramic straight tube to achieve better insulation effect and avoiding short-circuit phenomenon of an anode of an ion source metal wall and a filament cathode; by the design structure, the invention solves the problem that short circuit occurs to the ceramic insulation part of the seat body due to the metal plating and filament spraying and plasma bombardment in the research process of large-power ion source, greatly improves experiment safety coefficient and simultaneously prolongs the service life of the filament and the ceramic part.

Description

technical field [0001] The invention belongs to the technical field of ion sources, and in particular relates to an ion source filament seat structure. Background technique [0002] The ion source uses a hot tungsten filament as the discharge cathode, and the metal wall as the anode. Permanent magnets are arranged on the wall and end of the discharge chamber to generate a magnetic field to confine the plasma, resulting in high-density and uniform plasma. Generally speaking, one end flange of the ion source discharge chamber is arranged with filaments and air supply facilities, and the other end is used to extract ion beams. The filament is fixed on the end flange or on the wall of the discharge chamber. The support and insulation structure (also known as the filament seat structure) is an important part of the internal connection structure design of the ion source; since the tungsten filament cathode in the ion source needs to be electrically heated to about 3000K to emit t...

AI Technical Summary

Problems solved by technology

The insulation structure adopts a ceramic straight tube, and the molybdenum rod is set in it. This structure is often due to the fact that after the ion source has been working for a period of time, the tungsten material filament is sprayed on the outer wall of the ceramic straight tube to form a metal coating layer, resulting in the molybdenum rod (filament holder) and the ceramic filament holder. The outer surface of the straight tube and the metal flange of the base (also the discharge anode), the short circuit between the anode of the metal barrel wall of the ion source and the cathode of the filament, and the short circuit between the filaments cause the insulation structure to fail; at the same time, there is no protection at the connection between the filament and the support Susceptible to plasma bombardment, the local temperature is too high, which can easily cause the filament to fuse

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