US4241253A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Epithermal neutron detector
Assignee: Mobil Oil AS
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Filing: 1978-11-24
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Granted: 1980-12-23
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Expires: 1998-11-24
Abstract
Abstract A radioactivity well logging tool employs an epithermal neutron detector having a thermal neutron counter surrounded by a thermal neutron shield. Located between the counter and the shield is a neutron moderating material for slowing down epithermal neutrons penetrating the thermal neutron shield to enable their counting by the thermal neutron counter.
Inventors
- 👤 Linus S. Allen
- 👤 Wyatt W. Givens
- 👤 William R. Mills, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 02:58
CPC Classifications
H; H01; H01J; H01J47/00; H01J47/12; G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/10; G01V5/107
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
108 words
An epithermal neutron detector comprising: (a) a thermal neutron counter, (b) a thermal neutron shield surrounding said counter, and (c) an epithermal neutron moderating material located between said counter and said shield for slowing down epithermal neutrons which penetrate said shield to enable those neutrons to be more readily absorbed by said counter, the thickness of said moderating material and the ratio of the diameter of said counter to the outer diameter of said moderating material being such that said counter yields a maximized neutron counting rate greater than the highest possible counting rate obtainable when said counter completely fills the inside diameter of said thermal neutron shield.
Claim 2
Dependent Claim
108 words
An epithermal neutron detector comprising: (a) a thermal neutron counter, (b) a thermal neutron shield surrounding said counter, and (c) an epithermal neutron moderating material located between said counter and said shield for slowing down epithermal neutrons which penetrate said shield to enable those neutrons to be more readily absorbed by said counter, the thickness of said moderating material and the ratio of the diameter of said counter to the outer diameter of said moderating material being such that said counter yields a maximized neutron counting rate greater than the highest possible counting rate obtainable when said counter completely fills the inside diameter of said thermal neutron shield.
Claim 3
Dependent Claim
12 words
The detector of claim 1 wherein said counter is a proportional counter.
Claim 4
Dependent Claim
14 words
The detector of claim 2 wherein said proportional counter is filled with helium-3 gas.
Claim 5
Dependent Claim
33 words
The detector of claim 3 wherein the minimum diameter of said counter below which no improvement in neutron absorption is achieved by the moderated detector over an unmoderated detector is about one inch.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-23 | 1984-06-23 | 1984-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-23 | 1988-06-23 | 1988-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-23 | 1992-06-23 | 1992-12-23 | $7700.00 | Window Closed / Lapsed |