System for measuring earth formation thermal neutron lifetime utilizing a harmonically intensity modulated fast neutron source

Patent · Tue Dec 30 00:00:00 EST 1975

OSTI ID:4042789

Pitts, Jr, R W

A system is disclosed for measuring indications of the thermal neutron lifetime of earth materials in the vicinity of a well borehole. A harmonically intensity modulated source of fast neutrons is used to irradiate the earth formations in the vicinity of a borehole with fast neutrons at three different intensity modulation frequencies. Intensity modulated clouds of thermal neutrons at each of the three modulation frequencies are detected by a single spaced detector. The tangent of phase shift of the thermal neutron intensity with respect to the fast neutron population intensity is measured at each of the three frequencies. These measurements may be appropriately combined to derive the thermal neutron lifetime of earth materials in the vicinity of the borehole. (auth)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-33-029397
• Assignee: to Texaco Inc.
• Patent Number(s): US 3930152
• OSTI ID: 4042789
• Resource Relation: Patent File Date: 1974 Jul 17; Other Information: G01t1/16. Orig. Receipt Date: 30-JUN-76
• Country of Publication: United States
• Language: English

Related Subjects

N46200* -Instrumentation-Radiometric Instruments
N68100 - -Physics (Nuclear)-Neutron Interactions with Matter
N44420 -Environmental & Earth Sciences-Radiometric Techniques-Soil
440105* -Instrumentation-Radiation Instrumentation- Radiometric Instruments
*SOILS- NEUTRON TRANSPORT
*THERMAL NEUTRONS- NEUTRON FLUX
*WELL LOGGING- PULSED NEUTRON TECHNIQUES
BOREHOLES
MEASURING METHODS