Apparatus and method for increasing the sensitivity of a nuclear magnetic resonance probe

摘要

The discovery has been made that coil-to-ground parasitic losses substantially reduce the sensitivity of a nuclear magnetic resonance probe used in nuclear magnetic resonance analyses of lossy dielectic (i.e. , relatively conductive) samples, such as biological tissue. A probe circuit is disclosed in which a balancing impedance is inserted for substantially reducing the influence of coil-to-ground parasitics. The probe circuit resulting from the insertion of the balancing impedance markedly increases sensitivity. Concomittantly, the quality factor of the probe circuit and the signal-to-noise ratio of nuclear magnetic resonance signals are substantially improved. The disclosed probe circuit can be incorporated in nuclear magnetic resonance analysis systems where the sample coil is either implanted or placed on the surface of a sample; where the sample coil forms a portion of a large- scale imaging system; or the sample coil is used in a traditional analytical mode with a sample contained in a glass tube.