A Design of Short Dead-Time RF Coil and RF Switch for Low-Field NMR

Based on the ring-down signal generation principle of nuclear magnetic resonance (NMR), we presented here a design scheme of transmitting and receiving separated short dead-time radio frequency (RF) coil composed of loop-gap resonator (LGR) coil and solenoid coil in low-field NMR system, to improve transmission efficiency by optimizing tuning and matching network. We also designed a fast RF switch and driver to fulfill the requirement of the RF coil. Based on the simulation results, the short dead-time RF coil was fabricated and applied to a self-developed 9.51 MHz portable low-field NMR spectrometer. The NMR experiments showed that the dead-time was reduced to less than 10 μs, which verified the feasibility of the design scheme.