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US4431920A
Expired / Lapsed
US
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Ionizing radiation dose monitor using silicon-on-sapphire transistor
Assignee: United States Department of the Army
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Filing: 1982-04-14
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Granted: 1984-02-14
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Expires: 2002-04-14
Abstract
Abstract A reusable solid state device is disclosed which monitors ionizing radiat. The device is a silicon-on-sapphire n-channel MOS transistor having a back-channel leakage current which is proportional to total radiation dose. To return the monitor to its original reusable state, the drain-to-source transistor bias is reduced to zero while irradiating the device to an appropriate dose level.
Inventors
- 👤 Joseph R. Srour
- 👤 Orlie L. Curtis
- 👤 Siegfried Othmer
- 👤 Susan C. C. Chen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:35
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/02; G01T1/026
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
92 words
A circuit for monitoring radiation, the circuit comprising: a solid state switching device having gate, source and drain terminals; means for applying a first bias between the gate and source terminals; means for applying a bias between the drain and source terminals during irradiation of the device; means for applying a second bias between the gate and source terminals for a preselected measurement interval; means connected between the drain and source terminals for measuring back-channel leakage current while the second bias is applied; and means for reducing the drain-to-source bias to zero.
Claim 2
Dependent Claim
92 words
A circuit for monitoring radiation, the circuit comprising: a solid state switching device having gate, source and drain terminals; means for applying a first bias between the gate and source terminals; means for applying a bias between the drain and source terminals during irradiation of the device; means for applying a second bias between the gate and source terminals for a preselected measurement interval; means connected between the drain and source terminals for measuring back-channel leakage current while the second bias is applied; and means for reducing the drain-to-source bias to zero.
Claim 3
Dependent Claim
17 words
The structure set forth in claim 1 wherein the solid state switching device is a silicon-on-sapphire transistor.
Claim 4
Dependent Claim
41 words
The subject matter set forth in claim 1 wherein the means for applying the first and second bias conditions between the gate and source terminals comprises switching means having two states, each state corresponding to the application of a respective bias.
Claim 5
Dependent Claim
41 words
The subject matter set forth in claim 1 wherein the means for applying the first and second bias conditions between the drain and source terminals comprises switching means having two states, each state corresponding to the application of a respective bias.
Claim 6
Dependent Claim
109 words
A reusable ionizing radiation dose monitor comprising: a silicon-on-sapphire transistor having gate, source and drain terminals; first switching means for applying (a) a first bias between the gate and source terminals during radiation of the transistor; (b) a second bias between the gate and source terminals during measurement of back-channel leakage current flowing between the drain and source terminals; second switching means for (a) applying a first bias between the drain and source terminals during irradiation of the device; (b) reducing the drain-source bias to zero in the presence of sufficient radiation, after a measurement interval, thereby causing resetting of the transistor to a condition of low leakage current.
Claim 7
Dependent Claim
109 words
A reusable ionizing radiation dose monitor comprising: a silicon-on-sapphire transistor having gate, source and drain terminals; first switching means for applying (a) a first bias between the gate and source terminals during radiation of the transistor; (b) a second bias between the gate and source terminals during measurement of back-channel leakage current flowing between the drain and source terminals; second switching means for (a) applying a first bias between the drain and source terminals during irradiation of the device; (b) reducing the drain-source bias to zero in the presence of sufficient radiation, after a measurement interval, thereby causing resetting of the transistor to a condition of low leakage current.
Claim 8
Dependent Claim
93 words
A reusable method for monitoring ionizing radiation comprising the steps: biasing the drain-source terminals of a silicon-on-sapphire transistor with a preselected voltage; biasing the gate-source terminals of the transistor with a first voltage during irradiation of the transistor; biasing the gate-source terminals with a second voltage during measurement of the back-channel leakage current flowing between the drain and source terminals of the transistor; and reducing the drain-source voltage to zero, wherein the transistor is substantially returned to its original condition characterized by a low back-channel leakage current flow between drain and source terminals.
Claim 9
Dependent Claim
93 words
A reusable method for monitoring ionizing radiation comprising the steps: biasing the drain-source terminals of a silicon-on-sapphire transistor with a preselected voltage; biasing the gate-source terminals of the transistor with a first voltage during irradiation of the transistor; biasing the gate-source terminals with a second voltage during measurement of the back-channel leakage current flowing between the drain and source terminals of the transistor; and reducing the drain-source voltage to zero, wherein the transistor is substantially returned to its original condition characterized by a low back-channel leakage current flow between drain and source terminals.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-02-13 | 1987-08-15 | 1988-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-13 | 1991-08-15 | 1992-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-13 | 1995-08-15 | 1996-02-14 | $7700.00 | Window Closed / Lapsed |