METHOD OF INDIRECTLY MONITORING THE OUTPUT OF A PULSED NEUTRON SOURCE

摘要

The specification discloses a borehole tool for assaying for uranium and having a pulsed neutron source of the accelerator type and a detector for detecting delayed fission neutrons. In operation, the source is periodically actuated to produce very short neutron bursts having a duration of a few microseconds or less. Located adjacent the source is a gamma-ray detector for detecting delayed gamma rays emitted from oxygen in the formations when irradiated with neutrons and resulting from the reaction O16(n,p)N16->O16 + gamma . These gamma rays are recorded to obtain an indirect measure of the neutron output produced by the source.