Patent US4365159A successfully refreshed from Google Patents.
US4365159A
Expired / Lapsed
US
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Lithium-6 foil neutron detector
Assignee: United States Department of the Navy
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Filing: 1980-11-03
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Granted: 1982-12-21
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Expires: 2000-11-03
Abstract
Abstract A neutron detection apparatus is provided which includes a selected numberf flat surfaces of lithium-6 foil, and which further includes a gas mixture in contact with each of the flat surfaces for selectively reacting to charged particles emitted by or radiated from the lithium foil. A container is provided to seal the lithium foil and the gas mixture in a volume from which water vapor and atmospheric gases are excluded, the container having one or more walls which are transmissive to neutrons. Monitoring equipment in contact with the gas mixture detects reactions taking place in the gas mixture, and, in response to such reactions, provides notice of the flux of neutrons passing through the volume of the detector.
Inventors
- 👤 Charles A. Young
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 10:42
CPC Classifications
H; H01; H01J; H01J47/00; H01J47/12; H01J47/1227; H01J47/1238; H01J47/1244
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
154 words
Neutron detection apparatus comprising: a selected number of flat surfaces of lithium-6 foil, each said flat surface of lithium-6 foil comprising a flat lithium-6 sheet, the thickness of each of said sheets being less than the range of a triton particle through lithium; a gas mixture in contact with each of said flat lithium foil surfaces for selectively reacting to charged particles radiated from said lithium-6 foil, said gas mixture comprising a counting gas mixture which is readily ionized by triton particles passing through said counting gas mixture; container means for sealing said lithium foil and said reacting gas mixture within a volume from which water vapor and atmospheric gases are excluded, said container means having walls which are transmissive to neutrons; and monitoring means in contact with said gas mixture for detecting reactions in said gas mixture, and for providing an output which is proportional to the flux of neutrons through said apparatus.
Claim 2
Dependent Claim
154 words
Neutron detection apparatus comprising: a selected number of flat surfaces of lithium-6 foil, each said flat surface of lithium-6 foil comprising a flat lithium-6 sheet, the thickness of each of said sheets being less than the range of a triton particle through lithium; a gas mixture in contact with each of said flat lithium foil surfaces for selectively reacting to charged particles radiated from said lithium-6 foil, said gas mixture comprising a counting gas mixture which is readily ionized by triton particles passing through said counting gas mixture; container means for sealing said lithium foil and said reacting gas mixture within a volume from which water vapor and atmospheric gases are excluded, said container means having walls which are transmissive to neutrons; and monitoring means in contact with said gas mixture for detecting reactions in said gas mixture, and for providing an output which is proportional to the flux of neutrons through said apparatus.
Claim 3
Dependent Claim
54 words
The apparatus of claim 1 wherein said monitoring means comprises: a selected number of arrays of count wires which are enclosed within said container means and maintained in spaced parallel relationship with said sheets of lithium-6 foil; and electronic processing means external to said container means which is coupled to said count wire arrays.
Claim 4
Dependent Claim
54 words
The apparatus of claim 1 wherein: said container means comprises a hermetically sealed container of selected interior dimensions; and means are provided for suspending at least one of said flat sheets of lithium-6 foil within said container so that both surfaces of said suspended sheet are in contact with said proportional counting gas mixture.
Claim 5
Dependent Claim
39 words
The apparatus of claim 2 wherein: said container means comprises a hermetically sealed container having a selected number of flat interior surfaces; and one of said flat sheets of lithium-6 foil is bonded to each of said interior surfaces.
Claim 6
Dependent Claim
87 words
The apparatus of claim 2 wherein: said container means comprises a hermetically sealed container having a selected number of flat interior surfaces; means are provided for suspending one or more of said flat sheets of lithium-6 foil within said container so that all of said suspended sheets are in spaced parallel relationship with one another and with each of said flat interior surfaces of said container; and one of said flat sheets of lithium-6 foil is bonded to each of said flat interior surfaces of said container.
Claim 7
Dependent Claim
54 words
The apparatus of claim 5 wherein: one of said count wire arrays is maintained in spaced parallel relationship with each surface of said sheets of lithium-6 foil which is in contact with said counting gas, each of said arrays comprising a selected number of count wires which are maintained in closely spaced parallel relationship.
Claim 8
Dependent Claim
99 words
The apparatus of claim 6 wherein said electronic processing means comprises: means for maintaining a selected positive high voltage on each of said count wires of said count wire arrays; pulse discriminator means for distinguishing voltage pulses provided by said count wires arrays which are of sufficient magnitude to be considered as having been generated within said container by a reaction between a neutron and a lithium-6 nucleus; and scaler means coupled to said pulse discriminator means for representing the level of neutron activity proximate to said container means in response to successive pulse outputs of said pulse discriminator.
Claim 9
Dependent Claim
63 words
The apparatus of claim 7 wherein: the spacing between said sheets of lithium-6 foil is selected to form layers of counting gas which are sufficiently thin that a gamma-ray passing through one of said gas layers is unable to generate a voltage pulse which is indistinguishable from a voltage pulse resulting from one of said reactions between a neutron and a lithium-6 nucleus.
Claim 10
Dependent Claim
21 words
The apparatus of claim 7 wherein; said counting gas mixture comprises a mixture of 90% argon gas and 10% methane gas.
Claim 11
Dependent Claim
21 words
The apparatus of claim 7 wherein: said counting gas mixture comprises a mixture of 80% argon gas and 20% isobutane gas.
Claim 12
Dependent Claim
24 words
The apparatus of claim 7 wherein: said container includes walls in parallel relationship with said sheets of lithium-6 foil which are formed of brass.
Claim 13
Dependent Claim
122 words
Neutron detection apparatus comprising: a plurality of flat sheets of lithium-6 foil which are stacked in spaced-apart parallel relationship; a selected counting gas mixture which is in contact with a number of surfaces of said sheets of lithium-6 foil; an array of count wires in spaced parallel relationship with each of the surfaces of said lithium sheets which is in contact with said counting gas; container means for enclosing said lithium-6 sheets, said counting gas, and said count wire arrays in a hermetically sealed chamber, one or more of the walls of said chamber being formed of material which is transmissive to neutrons; and means penetrating said container means for enabling said count wires to be electrically coupled to electronic processing equipment.
Claim 14
Dependent Claim
122 words
Neutron detection apparatus comprising: a plurality of flat sheets of lithium-6 foil which are stacked in spaced-apart parallel relationship; a selected counting gas mixture which is in contact with a number of surfaces of said sheets of lithium-6 foil; an array of count wires in spaced parallel relationship with each of the surfaces of said lithium sheets which is in contact with said counting gas; container means for enclosing said lithium-6 sheets, said counting gas, and said count wire arrays in a hermetically sealed chamber, one or more of the walls of said chamber being formed of material which is transmissive to neutrons; and means penetrating said container means for enabling said count wires to be electrically coupled to electronic processing equipment.
Claim 15
Dependent Claim
57 words
The apparatus of claim 12 wherein: said container means comprises a container having top and bottom walls which are in parallel relationship with said flat sheets of lithium-6 foil, said top and bottom walls each comprising a flat structure having edges which are all of greater length than the distance which separates said top and bottom walls.
Claim 16
Dependent Claim
38 words
The apparatus of claim 13 wherein: said top wall and said bottom wall each comprises a structure having edges which are 12 inches or less the distance separating said top and bottom walls being less than one inch.
Claim 17
Dependent Claim
32 words
The apparatus of claim 14 wherein: each of said arrays of count wires comprises a selected number of wires maintained in parallel relationship at a spacing which is less than an inch.
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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) | 1985-12-20 | 1986-06-21 | 1986-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-20 | 1990-06-21 | 1990-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-20 | 1994-06-21 | 1994-12-21 | $7700.00 | Window Closed / Lapsed |