Patent US3835329A successfully refreshed from Google Patents.
US3835329A
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Method of measuring fast neutron flux using thermoluminescent dosimeter
Assignee: United States Atomic Energy Commission
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Filing: 1973-08-23
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Granted: 1974-09-10
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Expires: 1993-08-23
Abstract
Abstract Thermoluminescent phosphors which are susceptible to neutron activation are exposed to a mixed field of radiation. Thermoluminescence resulting from prompt gamma irradiation is removed by a short period of annealing at a high temperature. The phosphors are then stored in a shielded chamber maintained at a sufficiently low temperature to allow accumulation of radiation dose produced by radionuclides formed on neutron activation. The thermoluminescence attributable to this self-irradiation dose is read and correlated to neutron flux or dose. Through use of separate phosphor materials having different threshold energies for neutron activation, energy spectra of fast neutron flux is obtained.
Inventors
- 👤 P Moran
- 👤 D Pearson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:57
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/02; G01T1/10; G01T1/11
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
33 words
The method of claim 1 wherein both said first and second amounts of stored radiation energy are released as thermoluminescence and are photometrically read to determine total radiation flux and fast neutron fluence.
Claim 2
Dependent Claim
35 words
The method of claim 1 wherein said step of shielding said phosphors is accomplished by maintaining said phosphors at a cryogenic temperature and both said heating and reading steps are begun at said cryogenic temperature.
Claim 3
Dependent Claim
30 words
The method of claim 1 wherein the temperature at which said annealing step is performed is in excess of the temperature range at which said subsequent heating step is performed.
Claim 4
Dependent Claim
36 words
The method of claim 1 wherein said phosphor consists of a substantially pure metallic fluoride salt, said salt being maintained at a temperature below 100* K. while said second amount of stored radiation energy is produced.
Claim 5
Dependent Claim
12 words
The method of claim 5 wherein said phosphor consists essentially of CaF2.
Claim 6
Dependent Claim
38 words
The method according to claim 1 wherein a plurality of said phosphor materials each having a different energy threshold for neutron absorption are exposed, annealed, shielded, heated and photometrically read to determine energy spectrum of said neutron fluence.
Claim 7
Dependent Claim
17 words
The method of claim 7 wherein said plurality of phosphor materials comprise 7LiF, Mg2SiO4:Tb, ZnO:Tm and CaSO4:Dy.
Claim 8
Dependent Claim
33 words
The method of claim 1 wherein said step of shielding said phosphor is performed at near ambient temperature and said phosphor is selected from the group of phosphor materials comprising 7LiF and CaSO4:Dy.
Claim 9
Dependent Claim
44 words
The method of claim 9 wherein said phosphor is CaSO4:Dy and said steps of heating and reading said phosphor are performed after shielding for a period of one day to determine thermal neutron fluence and again after fourteen days to determine fast neutron fluence.
References Cited (Backward Citations)
US3562480A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-09 | 1978-03-11 | 1978-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-09 | 1982-03-11 | 1982-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-09 | 1986-03-11 | 1986-09-10 | $7700.00 | Window Closed / Lapsed |