Cooling Large HTS Magnet Coils using a Gas Free-convection Cooling Loop Connected to Coolers

[摘要] The cool-down and liquefaction of helium in free convection cooling loops has been demonstrated in superconducting magnets greater than 2 meters in diameter. At 4.4K, temperature drops between the magnet hot spot and the coolers of less than 0.2 K have been achieved in large coils that are more than 1 meter from the coolers. At temperatures greater than 20 K, larger temperature drops between the magnet and the coolers are permitted. This paper shows that free-convection gas cooling can be viable for both cooling and cooling down large HTS magnets. This paper presents the flow circuit parameters needed to achieve a reasonable cool-down time and a low temperature drop between the magnet and the cooler cold heads with no liquid cryogen in the loop.

[发布机构] Lawrence Berkeley Laboratory, Berkeley; CA; 94720, United States^1

[关键词] Down time;Flow circuits;Free convection cooling;Gas cooling;Hot spot;HTS magnet;Low temperatures;Temperature drops