Development of temperature measurement control unit for cryosorption pump

Abstract

For the future development needs of fusion, CFETR (China Fusion Engineering Test Reactor, referred to as CFETR) negative ion based neutral beam injector (referred to as NNBI) verification prototype is designed with large cryosorption pump as the main vacuum acquisition equipment. The temperature of the cryogenic adsorption surface and the radiation shield baffle need to be monitored in real time at key locations. In order to control the regeneration of the cryosorption pump, the ability to heat the cryogenic adsorption surface to a set temperature is required. A multi-channel temperature measurement control unit based on the STM32 was designed to meet the temperature measurement requirements of the cryosorption pump of the CFETR NNBI verification prototype, which operates in a complex radiation and electromagnetic environment. The temperature measurement range is from 4 K to 325 K in the helium zone and from 70 K to 450 K in the nitrogen zone. It not only measures 8 points simultaneously and transmits the data remotely to the upper computer, but also allows the temperature to be set by the upper computer. In addition, it is possible to control the regeneration process of the cryosorption pump by controlling the heating of the heating wire via the STM32. The temperature measurement control unit has been tested on a small cryosorption pump bench, it is capable of multi-channel temperature measurement and real-time display on the upper computer's display system,it can also control the heating. It not only lays the foundation for the construction of a temperature measurement control unit for the NNBI verification prototype cryosorption pump, but also provides a design reference for similar requirements.