在边缘场成像实验中,支撑样品运动的机械结构缺少调节环节,运动形式单一,样品外围共振线圈采用固定化形式,无法满足超强磁场周边不规则梯度场变化的要求.本文在前期研究基础上提出了一种多功能调节机械结构,该结构具有独立调节样品以及共振线圈姿态和位置的功能.在一维边缘场成像中保证样品和共振线圈的中心轴线可同时与梯度场中磁场方向平行,并且实现了成像过程中样品沿着磁场方向升降的方式;在三维边缘场魔角旋转成像过程中,可以保证样品和共振线圈均与磁场方向呈魔角角度,并且在样品旋转成像时一旦出现回波信号不好或者无回波的情况,还可以实现样品的实时性暂停和回转,以重新获取样品在该位置的信号.更重要的是该机械结构在三维成像过程中增加了样品的升降功能,可以在更高梯度场中获取样品更精细的图像.
In stray field imaging (STRAFI) experiments, mechanical structures which support the sample motion lack the adjustable function.In addition, the form of the sample motion is single,and the resonance coil is immobilized.These shortcomings cannot satisfy the direction of the irregular gradient at the fringe of the superconducting magnet.This paper proposes a multi-functional adjustable mechanical structure based on the research of the STRAFI.This mechanism involves the function to adiust the posture and the position of the sample as well as the resonance coil in STRAFI.It can guarantee the sample and resonance coil to be parallel to the direc tion of the magnet,and enables the sample to be lifted along the magnet direction when doing one-dimension (1D) STRAFI.In threedimension (3D) STRAFI magic angle spinning (MAS),the adjustable function can ensure the magic angle between the direction of the magnet and the center of the sample and resonance coil.The mechanism can also achieve the real-time susceptive and tuning back when the echo is poor or even is absent in STRAFI-MAS. Furthermore, this mechanism integrates the lifting function into the 3D STRAFI-MAS,which can measure finer samples in higher-gradient fields in STRAFI.