US5068532A
Expired / Lapsed
US
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Analysis using neutrons
Assignee: United Kingdom Atomic Energy Authority
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Filing: 1990-03-19
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Granted: 1991-11-26
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Expires: 2010-03-19
Abstract
Abstract A tool suitable for borehole logging, including production oilwell borehole logging, contains a radioisotope neutron source (14), a fast neutron detector (15) and a gamma-ray detector (16). Gamma-ray detection events are selected for building spectra by coincidence or anticoincidence with detection of the associated neutron. In a development, additional information is derived from identification of which of a series of time intervals encompasses detection of a neutron after detection of a gamma-ray.
Inventors
- 👤 Malcolm R. Wormald
- 👤 Bruce W. Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:36
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/10; G01V5/101; G01V5/104
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
49 words
A method for analysis of material comprising irradiating the material with neutrons, detecting resultant gamma rays, detecting fast neutrons scattered from the material, and registering the number of gamma detection events at at least one selected energy which occur in coincidence or anticoincidence with detection of a scattered neutron.
Claim 2
Independent Claim
49 words
A method for analysis of material comprising irradiating the material with neutrons, detecting resultant gamma rays, detecting fast neutrons scattered from the material, and registering the number of gamma detection events at at least one selected energy which occur in coincidence or anticoincidence with detection of a scattered neutron.
Claim 3
Independent Claim
70 words
A method for analysis of material comprising irradiating the material with fast neutrons, detecting resultant gamma-rays, detecting fast neutrons scattered from the material, effecting a registration of the number of gamma-ray detection events which occur at at least one selected energy, and including in the registration information as to which, if any, of two or more predetermined time intervals after the gamma-ray detection event encompassed detection of a scattered neutron.
Claim 4
Independent Claim
70 words
A method for analysis of material comprising irradiating the material with fast neutrons, detecting resultant gamma-rays, detecting fast neutrons scattered from the material, effecting a registration of the number of gamma-ray detection events which occur at at least one selected energy, and including in the registration information as to which, if any, of two or more predetermined time intervals after the gamma-ray detection event encompassed detection of a scattered neutron.
Claim 5
Dependent Claim
83 words
Apparatus for analysis of material comprising a source of neutrons, a gamma-ray detector, a fast neutron detector, and means for registering the number of gamma detection events at at least one selected energy which occur in coincidence or anticoincidence with detection of a scattered neutron, the source of neutrons being such as to provide neutrons at an energy in excess of the threshold energy for the inelastic scattering reaction which, amongst those reactions of interest for the analysis, has the highest threshold energy.
Claim 6
Dependent Claim
83 words
Apparatus for analysis of material comprising a source of neutrons, a gamma-ray detector, a fast neutron detector, and means for registering the number of gamma detection events at at least one selected energy which occur in coincidence or anticoincidence with detection of a scattered neutron, the source of neutrons being such as to provide neutrons at an energy in excess of the threshold energy for the inelastic scattering reaction which, amongst those reactions of interest for the analysis, has the highest threshold energy.
Claim 7
Dependent Claim
113 words
Apparatus for analysis of material comprising a source of neutrons, the source of neutrons being such as to provide neutrons at an energy in excess of the threshold energy for the inelastic scattering reaction which, amongst those reactions of interest for the analysis, has the highest threshold energy, a gamma-ray detector, a fast neutron detector, registration means for effecting a registration of the number of gamma-ray detection events which occur at at least one selected energy, means for defining two or more predetermined time intervals after each gamma-ray detection event, the said registration means including in the registration information as to which of the said time intervals encompassed detection of a scattered neutron.
Claim 8
Dependent Claim
113 words
Apparatus for analysis of material comprising a source of neutrons, the source of neutrons being such as to provide neutrons at an energy in excess of the threshold energy for the inelastic scattering reaction which, amongst those reactions of interest for the analysis, has the highest threshold energy, a gamma-ray detector, a fast neutron detector, registration means for effecting a registration of the number of gamma-ray detection events which occur at at least one selected energy, means for defining two or more predetermined time intervals after each gamma-ray detection event, the said registration means including in the registration information as to which of the said time intervals encompassed detection of a scattered neutron.
Claim 9
Dependent Claim
57 words
Apparatus as claimed in claim 4, wherein said defining means defines three time intervals predetermined to correspond respectively with reactions likely to have occurred within a predetermined first distance from the source, reactions likely to have occurred between said first distance and a predetermined second distance, and reactions likely to have occurred beyond said predetermined second distance.
Claim 10
Dependent Claim
14 words
Apparatus as claimed in claim 3, wherein the source is a radioisotope neutron source.
Claim 11
Dependent Claim
43 words
Apparatus as claimed in claim 3, wherein the source and the detectors are assembled, together with shielding for preventing direct passage of neutrons or gamma-rays from the source to the detectors, in a tubular housing suitable for feeding into an oil production borehole.
Claim 12
Dependent Claim
14 words
Apparatus as claimed in claim 4, wherein the source is a radioisotope neutron source.
Claim 13
Dependent Claim
14 words
Apparatus as claimed in claim 5, wherein the source is a radioisotope neutron source.
Claim 14
Dependent Claim
43 words
Apparatus as claimed in claim 4, wherein the source and the detectors are assembled, together with shielding for preventing direct passage of neutrons or gamma-rays from the source to the detectors, in a tubular housing suitable for feeding into an oil production borehole.
Claim 15
Dependent Claim
43 words
Apparatus as claimed in claim 5, wherein the source and the detectors are assembled, together with shielding for preventing direct passage of neutrons or gamma-rays from the source to the detectors, in a tubular housing suitable for feeding into an oil production borehole.
Claim 16
Dependent Claim
43 words
Apparatus as claimed in claim 6, wherein the source and the detectors are assembled, together with shielding for preventing direct passage of neutrons or gamma-rays from the source to the detectors, in a tubular housing suitable for feeding into an oil production borehole.
Claim 17
Dependent Claim
43 words
Apparatus as claimed in claim 8, wherein the source and the detectors are assembled, together with shielding for preventing direct passage of neutrons or gamma-rays from the source to the detectors, in a tubular housing suitable for feeding into an oil production borehole.
Claim 18
Dependent Claim
43 words
Apparatus as claimed in claim 9, wherein the source and the detectors are assembled, together with shielding for preventing direct passage of neutrons or gamma-rays from the source to the detectors, in a tubular housing suitable for feeding into an oil production borehole.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-11-25 | 1995-05-27 | 1995-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-11-25 | 1999-05-27 | 1999-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-11-25 | 2003-05-27 | 2003-11-26 | $7700.00 | Window Closed / Lapsed |