Abstract: According to some embodiments, low-temperature (cryogenic) nuclear magnetic resonance (NMR) probe fixed capacitors include thermally-conductive dielectric layers serving to thermally connect the capacitors to a cryogenic heat sink. For example, a sapphire layer may be metalized on opposite sides to form copper capacitor plates, and along an edge to form a copper heat sink contact. Heat generated by RF currents during an operation of an NMR circuit including such a capacitor is discharged through the thermally-conductive dielectric to the heat sink. Cooling cold-probe circuit components such as capacitors through thermally-conductive capacitor dielectrics allows reducing perturbations introduced into the circuit by components such as heat sinks.

Abstract: According to one aspect, the low-frequency (e.g. lock channel) performance of a nuclear magnetic resonance (NMR) saddle-shaped, distributed-capacitance radio-frequency (RF) coil is improved by connecting a pair of auxiliary inductors across a plurality of leads extending upward from the coil upper ring. The upward-extending leads can be formed from the same foil as a main coil structure. The auxiliary inductors are separated from the coil window, so that magnetic susceptibility discontinuities introduced by the auxiliary inductors can be compensated for. In one embodiment, two half-toroid auxiliary inductors are positioned to form a full toroid shape. Some lost high-frequency performance can be recovered by using a split capacitance band positioned over the lower coil ring. The split capacitance band allows capacitance tuning while maintaining an RF current path close to the coil window.

Abstract: A sample probe and apparatus are provided for magnetic resonance experiments. The probe includes a coil simultaneously tunable to at least two different frequencies. The coil includes a section having a scroll configuration and defines a core into which a sample can be inserted. A multi-resonant circuit transmits RF energy to the coil at two or more different frequencies for exciting nuclei of the sample. The apparatus includes a coil having a scroll configuration. RF transmission circuitry transmits RF energy to the coil at two or more different frequencies. RF receiving circuitry receives an RF signal responsive to excitation. A coil is magnetically coupled with a sample at an RF frequency.

Abstract: NMR coils are formed from transmission line comprising a tuned LC circuit determined substantially from the distributed capacitance and inductance of the transmission line operated in common mode. Introduction of gaps staggered between opposite conductors of 2-conductor transmission line contribute a desired distributed capacitance with reduced effective inductance to sustain resonant behavior at higher frequency than achievable with conventionally tuned coils and with relaxation of dimensional constraints as the resonant half wavelength approaches coil dimensions.

Abstract: NMR coils are formed from transmission line comprising a tuned LC circuit determined substantially from the distributed capacitance and inductance of the transmission line operated in common mode. Introduction of gaps staggered between opposite conductors of 2-conductor transmission line contribute a desired distributed capacitance with reduced effective inductance to sustain resonant behavior at higher frequency than achievable with conventionally tuned coils and with relaxation of dimensional constraints as the resonant half wavelength approaches coil dimensions.