| 摘要 |
<p>The specification describes a method and apparatus for logging the formations surrounding a borehole. The apparatus consists of a pulsed source for emitting bursts of high energy neutrons. Radiation emanating from the formations is detected by a radiation detector. The apparatus includes circuit means for generating from the detected radiations first and second measurements of the macroscopic thermal neutron absorption cross-section of the formations. Finally, the apparatus includes circuit means for selectively recording one of the measurements of the macroscopic thermal neutron absorption cross-section of the formations. The selection is based on the macroscopic thermal neutron absorption cross-section of the formation. csm/</p> |
