Downhole NMR tool with receiver on sensor

An apparatus for performing a downhole nuclear magnetic resonance (NMR) experiment on a subsurface material in a volume of interest, the apparatus comprising:

• a carrier configured to be conveyed through a borehole penetrating the subsurface material;
• an NMR sensor assembly disposed on the carrier and comprising a static magnetic field source configured to polarize nuclei of the subsurface material in the volume of interest and an antenna configured to receive NMR signals;
• and
• a receiver circuit disposed on the NMR sensor assembly and configured to process received NMR signals to perform the downhole NMR experiment, wherein the receiver circuit comprises a programmable gain module that receives a signal from the antenna and provides an input signal to a filter that provides a filtered signal to an analog-to-digital converter, the receiver circuit further comprising a feedback loop from the analog-to-digital converter to the programmable gain module to increase dynamic range while avoiding saturation;
• wherein (i) the receiver circuit is disposed in a pressure-excluding enclosure and (ii) the antenna, the static magnetic field source, and the pressure-excluding enclosure are disposed in a pressure-balancing fluid that is at least partially enclosed by an enclosure of non-metallic material.