Cryogenic Probe with Low-Loss Transmission Line for Nuclear Magnetic Resonance

Abstract

In the design and construction of NMR probes, it is frequently useful to have the tuning elements remote from the NMR coil and sample space. In such cases, a transmission line is an integral part of the resonance circuit. The characteristics of transmission lines are considered and a design for a low-loss transmission line probe is given. The impedance transformation characteristics of low-loss transmission lines are used in several cryogenic probes including singly and doubly tuned probes. Although a low-loss transmission line improves the efficiency of the probe, it may not be the dominant factor in maximizing energy transfer to the NMR coil.