US3702932A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Melting cryogen cooling for radiation logging probe
Assignee: United States Atomic Energy Commission
•
Filing: 1971-04-15
•
Granted: 1972-11-14
•
Expires: 1991-04-15
Abstract
Abstract A borehole logging probe for mineral or petroleum exploration is disclosed having a californium-252 neutron source for activating elements adjacent to the borehole and a solid state detector for sensing resulting radiation. The probe includes an elongated watertight housing having a shielded compartment for the neutron source, and a thermally insulated compartment for containing the radiation detector. A reservoir is filled with a fusible solid cryogen and located within the insulated compartment adjacent to the detector with a thermal conduction member disposed to cool the radiation detector by transferring heat to the solid cryogen.
Inventors
- 👤 Allan B Tanner
- 👤 Frank E Senftle
- 👤 Robert M Moxham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:34
CPC Classifications
G; G21; G21G; G21G4/00; G21G4/02; F; F25; F25D; F25D3/00; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/10; G01V5/101; G01V5/102; F25D19/00; F25D19/006
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
141 words
An improved neutron logging probe disposed within a sealed housing, comprising: a. a Cf-252 neutron source for establishing neutron flux in the vicinity of said probe; b. a lithium drifted germanium radiation detector for sensing radiation produced by the interaction of said neutron flux with substances outside said housing; c. a sealed reservoir disposed adjacent to said detector; d. solid cryogen material selected from the group consisting of propane, chlorodifluoromethane and dichlorodifluoromethane disposed in said reservoir; and e. a straight tubular thermal conduction member longitudinally disposed through said reservoir in thermal communication with said solid cryogen material and sealingly penetrating both ends of said reservoir, said thermal conduction member being closed at one end with an end plate disposed in thermal communication with said radiation detector and at the opposite end with a removable plug member for admitting a liquid refrigerant.
Claim 2
Dependent Claim
141 words
An improved neutron logging probe disposed within a sealed housing, comprising: a. a Cf-252 neutron source for establishing neutron flux in the vicinity of said probe; b. a lithium drifted germanium radiation detector for sensing radiation produced by the interaction of said neutron flux with substances outside said housing; c. a sealed reservoir disposed adjacent to said detector; d. solid cryogen material selected from the group consisting of propane, chlorodifluoromethane and dichlorodifluoromethane disposed in said reservoir; and e. a straight tubular thermal conduction member longitudinally disposed through said reservoir in thermal communication with said solid cryogen material and sealingly penetrating both ends of said reservoir, said thermal conduction member being closed at one end with an end plate disposed in thermal communication with said radiation detector and at the opposite end with a removable plug member for admitting a liquid refrigerant.
Claim 3
Dependent Claim
134 words
In a neutron logging probe, including a Cf-252 radiation source and a lithium drifted germanium radiation detector, the improved method of cooling said detector comprising: a. disposing a solid cryogenic material selected from the group consisting of propane, chlorodifluoromethane and dichlorodifluoromethane within a sealed reservoir adjacent to said detector; b. thermally coupling said detector to said solid cryogenic material with a straight tubular thermal conduction member having a removable plug at the end opposite said detector; c. allowing said solid cryogenic material to melt and absorb heat from said detector through said thermal conduction member; and d. refreezing said cryogenic material by removing said plug; inserting an open spout of an otherwise closed container of liquid nitrogen part way down said tubular member and gravitating liquid nitrogen into said tubular member from said container.
Claim 4
Dependent Claim
134 words
In a neutron logging probe, including a Cf-252 radiation source and a lithium drifted germanium radiation detector, the improved method of cooling said detector comprising: a. disposing a solid cryogenic material selected from the group consisting of propane, chlorodifluoromethane and dichlorodifluoromethane within a sealed reservoir adjacent to said detector; b. thermally coupling said detector to said solid cryogenic material with a straight tubular thermal conduction member having a removable plug at the end opposite said detector; c. allowing said solid cryogenic material to melt and absorb heat from said detector through said thermal conduction member; and d. refreezing said cryogenic material by removing said plug; inserting an open spout of an otherwise closed container of liquid nitrogen part way down said tubular member and gravitating liquid nitrogen into said tubular member from said container.
References Cited (Backward Citations)
US2711084A
Cited
US3253423A
Cited
US3360943A
Cited
US3496360A
Cited
US3611746A
Cited
US3545226A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-14 | 1976-05-15 | 1976-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-14 | 1980-05-15 | 1980-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-14 | 1984-05-15 | 1984-11-14 | $7700.00 | Window Closed / Lapsed |