| 摘要 |
PROBLEM TO BE SOLVED: To interrupt a process generating noise and decrease a noise by forming a magnetic resonance tomography device so that natural oscillation form of a gradient coil system and Lorentz force are directed vertical to each other as much as possible. SOLUTION: A noise is caused by acting Lorentz force on a conductor part of a gradient coil then being oscillated the gradient coil. Natural oscillation behavior of the gradient coil system is decided by The number and form of natural oscillation. If Lorentz force and natural oscillation form are crossed at right angles to all points of the gradient coil system and all natural oscillation form, scalar product always becomes zero. Such the gradient coil system generates no noise. When a natural oscillation form 4 for such a supporter structure is multiplicated to Lorentz force distribution, a curved line which extends to upper and lower sides of a crossed line S is generated. When the curbed line is integrated along the crossed line S, an apparently little characterization factor is generated. That means that noise is small.
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