The vacuum system of the J-TEXT tokamak

Abstract

A new vacuum system is designed and developed on the Joint Texas Experimental tokamak (J-TEXT), which consists of two pumping stations, a Taylor discharge cleaning (TDC) system and gas puffing. With this system, the vacuum vessel of the J-TEXT tokamak can easily reach the vacuum conditions which allow the operation of the machine. The sub-control system of the vacuum pumping systems with the self-protection function is reliable and easy to use. Inside the chamber, the base pressure can be lowered to 6.4×10⁻⁶ Pa, and the total leakage and outgassing rates in 12 h is below 1.5×10⁻⁸ Pa m³/s. Moreover, the TDC sub-system is used to clean the first facing walls of vacuum chamber to guarantee good wall conditions of the device before each run of the experimental campaign on the J-TEXT tokamak. The basic functions of the vacuum system meet the essential requirements for the present experiments on the J-TEXT tokamak.

Keywords:

• pumping system
• Taylor discharge cleaning
• J-TEXT tokamak

Acknowledgements

The authors are grateful to the vacuum group of the institute of plasma physics, Chinese Academy of Science and Southwest Institute of Physics for their assistance. Special appreciation is expressed to Mao Xinqiao for helpful discussion. This work was supported in part by the national basic research program of China with grant No. 2007ID105.