Study Of A Small Superconducting Magnet System Cooled By Pulse Tube Refrigerator

Pulse tube cooler has several advantages, such as higher reliability, lower mechanical vibration, lower magnetic noise and longer lifetime, since it has no moving parts at the cold end. It will replace the convenienal G-M cooler to cool the infrared sensors and superconducting magnets with the performance improvement of the pulse tube cooler in the temperature region of liquid helium. And it's also an ideal low-temperature cooler for cooling the small superconducting manget system.This paper reviews the development of the superconducting magnet system directly cooled by small low-temperature cooler, combined the performance of the pulse tube cooler, a small superconducting magnet system is designed cooled by a separated two-stage pulse tube cooler. The magnet coil can be charged with a current of 35A corresponding to a central field of 5T. The commercial software Fluent is used to simulate the temperature distribution of liquid helium dewar and ANSYS is used to simulate the distribution of magnetic field. The main research work is listed as follows:1. Design of a small scale superconducting magnet system cooled by pulse tube cooler.The small scale superconducting magnet is immerged into liquid helium and the liquid helium is used for cooling. The merit of this method is that the temperature of the magnet is uniform and the superconducting magnet can be cooled by the evaporation of the liquid helium when the magnet quenches. The incoming helium gas is pre-cooled which passes through a thin spiral stainless steel tube welded on regenerator using the first and second regenerators, and then flows into the liquid helium dewar. The top flange with fin of the dewar directly connected with the cold head of the two stage of the pulse tube cooler is used to condense the vapored saturated helium gas. The evaporated helium gas obtained by quench of the magnet is stored in ambient temperature container. The heat load of the cold head of the first stage (40K) and the second stage (4.2K) is 5.13W and 99.2W when the operating...