A 1.5T Liquid-Helium-Free Whole-body MRI Superconducting Magnet: Thermal Analysis and Cool-down Time Estimation

This paper focused on the thermal analysis and cool-down time estimation of a self-developed 1.5 T liquid-helium-free whole-body MRI superconducting magnet, which adopted solid thermal links connected to a two-stage GM cryocooler to realize the cool-down of the superconducting magnet. Under the combined effect of heat leakage and cooling power, the calculation results showed that the thermal shield will come to 45.44 K after about 309 h, and the superconducting magnet precooling to 77 K with liquid-nitrogen will come to 3.73 K after about 372 h. Without liquid-helium, the 1.5 T whole-body MRI superconducting magnet can be cooled to the low-temperature for superconductivity using the special heat conduction structure.