US4884288A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Neutron and gamma-ray moisture assay
Assignee: Commonwealth Scientific and Industrial Research Organisation
•
Filing: 1986-12-29
•
Granted: 1989-11-28
•
Expires: 2006-12-29
Abstract
Abstract A method and apparatus is disclosed for determining the moisture content of a substance irradiated by a fast neutron and gamma ray source wherein a fast neutron moderator is positioned in the path of the fast neutrons and gamm rays transmitted through the substance. A unitary thick Li glass or LiI glass detector is positioned behind or surrounded by the fast neutron moderator and detects both slow neutrons and gamma rays. Simplified counting circuitry utilizing a single channel analyser determines the intensities of the detected slow neutrons and gamma rays enabling the moisture content of the substance.
Inventors
- 👤 Brian D. Sowerby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:22
CPC Classifications
G; G01; G01N; G01N23/00; G01N23/02; G01N23/06; G01N23/09
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
147 words
A system for measuring the moisture content of a substance comprising: a fast neutron and gamma-ray source disposed in the vicinity of the substance to irradiate the substance with fast neutrons and gamma-rays, a fast neutron moderator positioned in the path of the fast neutrons and gamma-rays transmitted through the substance, a unitary Li glass or LiI slow neutron detector having a thickness ranging from 5 mm to 50 mm which can also detect gamma-rays positioned behind or surrounded by the fast neutron moderator to detect slow neutrons, corresponding to or proportional to fast neutrons transmitted through the substance and to detect gamma-rays transmitted through the substance, counting means operatively associated with the detector for determining the intensities of the detected gamma-rays and the detected slow neutrons, and calculating means operatively associated with the counting means for calculating the moisture content of the substance from the intensities.
Claim 2
Independent Claim
147 words
A system for measuring the moisture content of a substance comprising: a fast neutron and gamma-ray source disposed in the vicinity of the substance to irradiate the substance with fast neutrons and gamma-rays, a fast neutron moderator positioned in the path of the fast neutrons and gamma-rays transmitted through the substance, a unitary Li glass or LiI slow neutron detector having a thickness ranging from 5 mm to 50 mm which can also detect gamma-rays positioned behind or surrounded by the fast neutron moderator to detect slow neutrons, corresponding to or proportional to fast neutrons transmitted through the substance and to detect gamma-rays transmitted through the substance, counting means operatively associated with the detector for determining the intensities of the detected gamma-rays and the detected slow neutrons, and calculating means operatively associated with the counting means for calculating the moisture content of the substance from the intensities.
Claim 3
Dependent Claim
13 words
The system as defined in claim 1 wherein the detector is Li glass.
Claim 4
Dependent Claim
15 words
The system as defined in claim 1 wherein the detector is disposed opposite the source.
Claim 5
Dependent Claim
18 words
The system as defined in claim 1 wherein the detector is of a thickness greater than 5 mm.
Claim 6
Dependent Claim
32 words
The system as defined in claim 1 wherein the counting means is set up to detect the intensities of the slow neutrons and the transmitted gamma-rays in selected substantially non-overlapping energy ranges.
Claim 7
Dependent Claim
29 words
The system as defined in claim 5 wherein the energy range for determining the intensities of slow neutrons is selected so as to include a slow neutron intensity peak.
Claim 8
Dependent Claim
83 words
The system as defined in claim 1 wherein the substance is coal or coke and the calculating means calculates the moisture content of the coal or coke according to the algorithm: ##EQU2## where a, b, c and d are constants; I n and I on are measured neutron intensities with and without a sample of said coal or coke present respectively; and I.sub.γ and I o γ are measured gamma-ray intensities with and without a sample of the coal or coke present respectively.
Claim 9
Dependent Claim
22 words
A system as defined in claim 1 wherein said slow neutron detector has a thickness ranging from 5 mm to 40 mm.
Claim 10
Independent Claim
122 words
A method for measuring the moisture content of a substance comprising: (a) irradiating a side of the substance with gamma-rays and fast neutrons; (b) detecting gamma-rays transmitted through the substance and detecting slow neutrons, corresponding to or proportional to fast neutrons transmitted through the substance, with a unitary Li glass or LiI slow neutron detector having a thickness ranging from 5 mm to 50 mm which can also detect gamma-rays, said detector being surrounded by or positioned behind a fast neutron moderator disposed in the path of the transmitted gamma-rays and the transmitted fast neutrons; (c) determining intensities of the detected gamma-rays and the detected slow neutrons; and (d) calculating the moisture content of the substance from the determined intensities of (c).
Claim 11
Independent Claim
122 words
A method for measuring the moisture content of a substance comprising: (a) irradiating a side of the substance with gamma-rays and fast neutrons; (b) detecting gamma-rays transmitted through the substance and detecting slow neutrons, corresponding to or proportional to fast neutrons transmitted through the substance, with a unitary Li glass or LiI slow neutron detector having a thickness ranging from 5 mm to 50 mm which can also detect gamma-rays, said detector being surrounded by or positioned behind a fast neutron moderator disposed in the path of the transmitted gamma-rays and the transmitted fast neutrons; (c) determining intensities of the detected gamma-rays and the detected slow neutrons; and (d) calculating the moisture content of the substance from the determined intensities of (c).
Claim 12
Dependent Claim
12 words
The method as defined in claim 9 wherein the detector is LiI.
Claim 13
Dependent Claim
57 words
The method as defined in claim 9 wherein a gamma-ray and fast neutron source is disposed in the vicinity of the substance whereby gamma-rays and fast neutrons emanating from the source irradiate a side of the substance adjacent to the source and wherein the detector is disposed on the opposite side of the substance to the source.
Claim 14
Dependent Claim
18 words
The method as defined in claim 9 wherein the detector is of a thickness greater than 5 mm.
Claim 15
Dependent Claim
51 words
The method as defined in claim 9 wherein counting means for determining the intensities of the detected gamma-rays and slow neutrons is operatively associated with the detector and wherein the counting means is set up to detect the intensities of the detected gamma-rays and slow neutrons in selected non-overlapping energy ranges.
Claim 16
Dependent Claim
24 words
The method as defined in claim 13 wherein the selected energy range for determining the detected slow neutrons includes a slow neutron intensity peak.
Claim 17
Dependent Claim
81 words
The method as defined in claim 9 wherein the substance is coal or coke and the moisture content of the coal or coke is calculated according to the algorithm: ##EQU3## where a, b, c and d are constants; I n and I on are measured neutron intensities with and without a sample of said coal or coke present respectively; and I.sub.γ and I o γ are measured gamma-ray intensities with and without a sample of the coal or coke present respectively.
Claim 18
Dependent Claim
58 words
The method as defined in claim 10 wherein a gamma-ray and fast neutron source is disposed in the vicinity of the substance whereby the gamma-rays and fast neutrons emanating from the source irradiate a side of the substance adjacent to the source and wherein the detector is disposed on the opposite side of the substance to the source.
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) | 1992-11-27 | 1993-05-29 | 1993-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-27 | 1997-05-29 | 1997-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-27 | 2001-05-29 | 2001-11-28 | $7700.00 | Window Closed / Lapsed |