Composite support system for 1.5 T whole-body MRI cryostat

Abstract

Support system is one of the most critical components of any MRI cryostat in providing the structural integrity during operation and the transportation. We have designed and analyzed the behavior of the composite support structures designed for a 1.5 T MRI cryostat. Various design criteria including the mechanical strength of the composite support system, mechanical resonance frequency of the cryostat, the heat inleak to 4.2 K etc. need to be considered during designing of the composite support system. The dimensional constraints as well as requirements for structural stability and heat conduction to 4.2 K has been established after identification and consideration of problems associated with superconducting magnet support system in MRI. The design incorporates s-glass support straps with intermediate thermal intercepts at 60 K and has been designed to suspend ∼ 5 tons of cold mass. This paper briefly discusses the static and dynamic stress simulation of cryogenic support link of the MRI cryostat using ANSYS. Based on the material choice, the heat leaks down the cold mass support system to 4.2 K and to 60 K are calculated as 250mW and 4.6 W respectively. The spring constant of the support system is 2.79 × 108 Nm-1.