Single detector detection and characterization of thermal and epithermal neutrons from an earth formation

摘要

An apparatus for detecting thermal and epithermal neutrons. The apparatus includes a first radiation responsive element configured to absorb substantially all incident thermal neutrons and produce first light scintillations indicative of the absorbed thermal neutrons and a second radiation responsive element configured to produce second light scintillations indicative of at least epithermal neutrons that traverse the first radiation responsive element. Also disclosed are borehole logging methods and apparatuses for estimating formation properties using nuclear radiation, particularly an apparatus and method for estimating parameters of a formation. The method may include using neutron count rate information from a detector to model porosity or salinity. The apparatus includes a processor and storage subsystem with a program that, when executed, implements the method.