基于非谐振线圈的磁共振接收前端设计与实现

Design and implementation of receiving front-end based on non-resonant coil of magnetic resonance

文中介绍了一种基于非谐振线圈的磁共振接收前端的设计原理和电路实现,将商用谱仪上的多通道谐振探头改造为非谐振线圈结构,并设计了一款与非谐振线圈匹配的低噪声放大器(Low Noise Amplifier,LNA),不但能够较好地放大非谐振线圈接收的信号,还可以与后级的商用谱仪系统匹配使用,将信号传输到控制台进行数字化处理。在商用300MHz Bruker AVANCE III谱仪上,通过接收前端成功探测到了重水样品的NMR(Nuclear Magnetic Resonance)信号,与谐振电路相比,文中接收前端具有无需重新调谐的优势,实验结果初步验证了该接收前端宽频探测的可行性。

The design principle and implementation of a receiving front-end circuit based on a non-resonant coil of magnetic resonance are introduced.By modification of the probe from the commercial spectrometer into a non-resonant coil,a low noise amplifier(LNA) is designed,which not only can amplify the signal received by the non-resonant coil,but also can be matched with the commercial spectrometer system of the latter stage to transmit to the commercial spectrometer system for further digitization.The modified front-end is applied in a commercial 300 MHz Bruker AVANCE III spectrometer,which acquire NMR signal from deuteroxide.Compared with the commercial resonant circuit,the receiving front-end has an advantage of not need to be tuned again.These experimental results verify the feasibility of the receiving front-end to broadband detect.