Systems and methods to determine relative elemental concentrations from nuclear spectroscopy measurements

A method for determining a factor of yields to weights value in a borehole of a geological formation comprising:

• emitting neutrons, from a neutron generator, placed into the borehole in the geological formation, to cause capture and inelastic scattering events that generate photons;
• detecting the photons using one or more detectors;
• determining, via a processor, from the detected photons, at least one of:
• a ratio of photon counts between two detectors;
• or
• an apparent sigma;
• determining, via the processor, the factor of yields to weights value based at least in part on the at least one of:
• the ratio of photon counts between two detectors;
• or
• the apparent sigma;
• converting, via the processor, a plurality of relative yields of elements in the geological formation to a plurality of elemental concentrations using the factor of yields to weights value;
• and
• determining, via the processor, a property of the geological formation using at least one of the plurality of elemental concentrations.

A method comprising:

• emitting neutrons, out of a downhole tool placed into a borehole in a geological formation, to cause inelastic scattering events that generate photons;
• detecting the photons using a plurality of detectors;
• determining, via a processor, a count rate ratio of the photons between at least two of the plurality of detectors;
• determining, via the processor, a factor of yields to weights value based at least in part on the count rate ratio;
• converting, via the processor, a plurality of relative yields of corresponding elements in the geological formation to a plurality of elemental relative weights using the factor of yields to weights value;
• and
• determining, via the processor, a property of the geological formation using at least one of the plurality of elemental relative weights.