US4286165A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dosimeter for measuring skin dose and more deeply penetrating radiation
Assignee: United States Department of Energy
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Filing: 1979-07-05
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Granted: 1981-08-25
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Expires: 1999-07-05
Abstract
Abstract A personnel dosimeter includes a plurality of compartments containing thermoluminescent dosimeter phosphors for registering radiation dose absorbed in the wearer's sensitive skin layer and for registering more deeply penetrating radiation. Two of the phosphor compartments communicate with thin windows of different thicknesses to obtain a ratio of shallowly penetrating radiation, e.g. beta. A third phosphor is disposed within a compartment communicating with a window of substantially greater thickness than the windows of the first two compartments for estimating the more deeply penetrating radiation dose. By selecting certain phosphors that are insensitive to neutrons and by loading the holder material with netruon-absorbing elements, energetic neutron dose can be estimated separately from other radiation dose. This invention also involves a method of injection molding of dosimeter holders with thin windows of consistent thickness at the corresponding compartments of different holders. This is achieved through use of a die insert having the thin window of precision thickness in place prior to the injection molding step.
Inventors
- 👤 Donald E. Jones
- 👤 DeRay Parker
- 👤 Paul R. Boren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:21
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/02; G01T1/10; G01T1/11
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
314 words
A personnel dosimeter for measuring radiation dose to a wearer within a skin layer defined between density thickness limits comprising: a holder of thermoplastic material having a front face and a rear wall, said rear wall having an opening therein for access to a plurality of wells; a plug adapted to seat within said rear wall opening, said plug having a plurality of posts each of which corresponding to one of said plurality of wells to define a plurality of compartments for containing TLD phosphors behind windows of predetermined density thicknesses from the front face of said holder; a first window, within said front face at a first compartment, having a density thickness of at least about that of the lesser limit of said skin layer but no more than about the deeper limit of said skin layer; a second window, within said front face at a second compartment, having a density thickness substantially greater than that of said first window and that of the deeper limit of said skin layer, said second window density thickness is greater than that of said first window by at least 5% but no more than 100% of the average density thicness of the phosphors contained within said first and second compartments; a third window, within said front face at a third compartment, having a density thickness of more than that of said second window and more than that of the average density thickness of the phosphors within said first and second compartments to permit estimation of the dose of penetrating radiation into the body of the wearer and thereby determine the ratio of the net dose passing through said first and said second windows being absorbed within the thickness of phosphors within said first and second compartments whereby radiation dose to said defined skin layer can be determined as a function of said ratio of net dose.
Claim 2
Dependent Claim
314 words
A personnel dosimeter for measuring radiation dose to a wearer within a skin layer defined between density thickness limits comprising: a holder of thermoplastic material having a front face and a rear wall, said rear wall having an opening therein for access to a plurality of wells; a plug adapted to seat within said rear wall opening, said plug having a plurality of posts each of which corresponding to one of said plurality of wells to define a plurality of compartments for containing TLD phosphors behind windows of predetermined density thicknesses from the front face of said holder; a first window, within said front face at a first compartment, having a density thickness of at least about that of the lesser limit of said skin layer but no more than about the deeper limit of said skin layer; a second window, within said front face at a second compartment, having a density thickness substantially greater than that of said first window and that of the deeper limit of said skin layer, said second window density thickness is greater than that of said first window by at least 5% but no more than 100% of the average density thicness of the phosphors contained within said first and second compartments; a third window, within said front face at a third compartment, having a density thickness of more than that of said second window and more than that of the average density thickness of the phosphors within said first and second compartments to permit estimation of the dose of penetrating radiation into the body of the wearer and thereby determine the ratio of the net dose passing through said first and said second windows being absorbed within the thickness of phosphors within said first and second compartments whereby radiation dose to said defined skin layer can be determined as a function of said ratio of net dose.
Claim 3
Dependent Claim
23 words
The dosimeter of claim 1 wherein said plug within said rear wall is removable to expose TLD phosphors within said plurality of compartments.
Claim 4
Dependent Claim
45 words
The dosimeter of claim 1 wherein a fourth window having a density thickness substantially equal to that of said third window is included within said front face at a fourth TLD compartment, said fourth compartment containing a phosphor sensitive to neutrons, beta, gamma and X-radiation.
Claim 5
Dependent Claim
31 words
The dosimeter of claim 3 wherein TLD phosphors are disposed in said first, second and third compartments which are sensitive to beta, gamma, and X-radiation but substantially insensitive to neutron radiation.
Claim 6
Dependent Claim
39 words
The dosimeter of claim 4 wherein said first, second, and third compartments contain TLD phosphors selected from the group consisting of CaF 2 and Li 7 F and said fourth compartment contains a TLD phosphor including Li 6 F.
Claim 7
Dependent Claim
31 words
The dosimeter of claim 3 wherein said thermoplastic material contains particles of neutron-absorbing materials including only elements with atomic number less than about 10 distributed throughout the mass of the holder.
Claim 8
Dependent Claim
26 words
The dosimeter of claim 6 wherein said neutron-absorbing material is selected from the group consisting of BN, B 4 C, LiF, Li 2 BO 4 .
Claim 9
Dependent Claim
38 words
The dosimeter of claim 3 wherein there is included within said front face a fifth window having a density thickness equivalent to about that of an average eye lens at a fifth compartment for containing a TLD phosphor.
Claim 10
Dependent Claim
43 words
The dosimeter of claim 1 wherein said first window has a density thickness of about 4-10 mg/cm 2 , said second window a density thickness of about 30-100 mg/cm 2 and said third window a density thickness of about 500-1000 mg/cm 2 .
Claim 11
Dependent Claim
24 words
The dosimeter of claim 9 wherein said first window comprises a plastic material selected from the group consisting of polyethylene terephthalate and polycarbonate resins.
Claim 12
Dependent Claim
17 words
The dosimeter of claim 10 wherein said first window is of polyethylene terephthalate having an aluminized surface.
Claim 13
Dependent Claim
26 words
The personnel dosimeter of claim 1 wherein said holder is formed of a thermoplastic material selected from the group consisting of polypropylene, acrylonitrile-butadienestyrene and polycarbonate resins.
References Cited (Backward Citations)
US3399301A
Cited
US3761710A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-24 | 1985-02-23 | 1985-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-24 | 1989-02-23 | 1989-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-24 | 1993-02-23 | 1993-08-25 | $7700.00 | Window Closed / Lapsed |