磁谐振成像系统中高温超导螺旋线圈的温度特性

Study of Temperature Properties of the High Temperature Superconductor Spiral Coil

用混合积分方程与矩量法 ,对磁谐振成像系统中的以LaAlO3 为介质基片的高温超导YBaCuO螺旋线圈的温度特性进行了计算和分析 .YBaCuO材料的电导率及表面阻抗由增强的两流子模型计算得到 ,与传统的两流子模型不同 ,增强的两流子模型中考虑了超电子的散射和损耗 .将计算所得到的结果与测试结果进行比对 ,结果表明 :与采用传统两流子模型计算得到的YBaCuO的电磁特性相比 ,温度为 77K时 ,高温超导螺旋接收线圈的谐振频率的精度提高了 4 % 。

The temperature properties of spiral coil made of high temperature superconducting material YBaCuO thin film on LaAlO 3 substrate in magnetic resonance image system is analyzed by mixed potential integral combined with method of moment. The conductivity and surface impediment of YBaCuO material are provided by enhanced two-fluid model, in which, superelectrons scattering and loss are considered. This is different from the conventional two-fluid model. The simulated data are compared with the experimental results. It shows that accuracy in resonant frequency of high temperature superconducting spiral RF receive coil has 4% improvement and the accuracy in unload Q -factor has shown with one order improvement compared with the conventional two-fluid model.