Title :
Preliminary Mechanical Analysis of a 9.4-T Whole-Body MRI Magnet
Author :
Lankai Li ; Junsheng Cheng ; Zhipeng Ni ; Housheng Wang ; Yinming Dai ; Qiuliang Wang
Author_Institution :
Key Lab. of Appl. Supercond., Inst. of Electr. Eng., Beijing, China
Abstract :
A 9.4-T/800-mm superconducting magnet for whole-body magnetic resonance imaging system has been designed and will be constructed from NbTi conductors. Main coils wound on five aluminum alloy formers provide the center field strength of about 9.4 T. In addition, compensation coils wound on another aluminum alloy former are used to improve the field uniformity of the imaging region. The operating point of the inner main coil is very close to the critical properties of its wire, and its temperature margin is about 0.4 K. It is necessary to know the mechanical stress in the main coils during all operating conditions. The mechanical behavior of the main coils during winding, cooldown, and energizing is analyzed. The effects on mechanical disturbances are predicted, and one available method is proposed to reduce premature quench. In addition, the dimension variations and position changes due to pretension, thermal contraction, and magnetic compression are present.
Keywords :
aluminium alloys; biomedical MRI; biomedical equipment; cooling; internal stresses; niobium alloys; superconducting coils; superconducting magnets; titanium alloys; winding (process); NbTi; NbTi conductor; aluminum alloy former; center field strength; compensation coil; critical wire properties; dimension variation; field uniformity; inner main coil operating point; magnetic compression effect; magnetic flux density 9.4 T; main coil cooldown; main coil energizing; main coil mechanical behavior; main coil mechanical stress; main coil winding; mechanical disturbance; operating condition; position change; premature quench reduction; pretension effect; size 800 mm; superconducting magnet construction; superconducting magnet design; temperature margin; thermal contraction effect; whole-body MRI magnet mechanical analysis; whole-body magnetic resonance imaging system; Coils; Conductors; Equations; Magnetic resonance imaging; Stress; Superconducting magnets; Windings; MRI superconducting magnet; Magnetic resonance imaging (MRI) superconducting magnet; Mechanical disturbance; mechanical disturbance; mechanical stress;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2015.2396934
