Thermal Analysis of the 4 K Cryostat within a 1.5 T Conduction-Cooled Superconducting Magnet for Whole-body MRI Application

This paper presented the thermal analysis of the 4 K cryostat of a self-developed 1.5 T conduction-cooled superconducting magnet in order to assess the cooling without liquid helium. Through a two-stage GM cryocooler and some solid thermal links, the NbTi coils achieved 4 K for superconducting state. Whole-body MRI requirements can be satisfied by the superconducting magnet's electromagnetic design, which has a large bore and a homogenous magnetic field. It will take about 278 hours to reach the lowest temperature of 3.73 K through precooling the 4 K cryostat with liquid nitrogen (77 K). Additionally, the FED method was used to evaluate the 4 K cryostat's temperature distribution, and it was determined that the temperature range of 3.99–4.12 K was enough for the magnet to operate safely. The analysis showed that the 1.5 T liquid-helium-free superconducting magnet was feasible and economical, which will be crucial in preserving helium supplies and lowering healthcare expenses.