US4873444A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detection of surface impurity phases in high TC superconductors using thermally stimulated luminescence
Assignee: University of California
•
Filing: 1988-11-23
•
Granted: 1989-10-10
•
Expires: 2008-11-23
Abstract
Abstract Detection of surface impurity phases in high-temperature superconducting materials. Thermally stimulated luminescence has been found to occur in insulating impurity phases which commonly exist in high-temperature superconducting materials. The present invention is sensitive to impurity phases occurring at a level of less than 1% with a probe depth of about 1 μm which is the region of interest for many superconductivity applications. Spectroscopic and spatial resolution of the emitted light from a sample permits identification and location of the impurity species. Absence of luminescence, and thus of insulating phases, can be correlated with low values of rf surface resistance.
Inventors
- 👤 D. Wayne Cooke
- 👤 Muhammad S. Jahan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:14
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/02; G01T1/10; G01T1/11
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
49 words
A method for detecting insulating phases in samples of superconducting materials which comprises the steps of: irradiating the sample with ionizing radiation in order to induce charge trapping in the insulating phases; heating the irradiated sample to yield luminescence; and detecting the luminescence as a function of sample temperature.
Claim 2
Independent Claim
49 words
A method for detecting insulating phases in samples of superconducting materials which comprises the steps of: irradiating the sample with ionizing radiation in order to induce charge trapping in the insulating phases; heating the irradiated sample to yield luminescence; and detecting the luminescence as a function of sample temperature.
Claim 3
Dependent Claim
28 words
The method as described in claim 1, further comprising the step of spectroscopically resolving the luminescence during said irradiated sample heating step before said step of luminescence detecting.
Claim 4
Dependent Claim
28 words
The method as described in claim 1, further comprising the step of spatially resolving the luminescence during said irradiated sample heating step before said step of luminescence detecting.
Claim 5
Dependent Claim
30 words
The method as described in claim 2, further comprising the step of spatially resolving the luminescence during said irradiated sample heating step before said step of spectroscopically resolving the luminescence.
Claim 6
Dependent Claim
24 words
The method as described in claim 1, wherein said step of irradiating the sample with ionizing radiation comprises irradiating the sample with gamma radiation.
Claim 7
Dependent Claim
24 words
The method as described in claim 1, wherein said step of irradiating the sample with ionizing radiation comprises irradiating the sample with high-energy electrons.
Claim 8
Independent Claim
81 words
A method for locating insulating phases in samples of superconducting materials which comprises the steps of: irradiating the sample with ionizing radiation in order to induce charge trapping in the insulating phases; heating the irradiated sample to yield luminescence; scanning the surface of the sample with at least one optical fiber during said heating step; and detecting the luminescence transmitted by the at least one optical fiber as a function of sample temperature and optical fiber position on the sample surface.
Claim 9
Independent Claim
81 words
A method for locating insulating phases in samples of superconducting materials which comprises the steps of: irradiating the sample with ionizing radiation in order to induce charge trapping in the insulating phases; heating the irradiated sample to yield luminescence; scanning the surface of the sample with at least one optical fiber during said heating step; and detecting the luminescence transmitted by the at least one optical fiber as a function of sample temperature and optical fiber position on the sample surface.
Claim 10
Dependent Claim
35 words
The method as described in claim 7, further comprising the step of spectroscopically resolving the luminescence transmitted by the at least one optical fiber during said surface scanning step before said step of luminescence detecting.
Claim 11
Dependent Claim
24 words
The method as described in claim 7, wherein said step of irradiating the sample with ionizing radiation comprises irradiating the sample with gamma radiation.
Claim 12
Dependent Claim
24 words
The method as described in claim 7, wherein said step of irradiating the sample with ionizing radiation comprises irradiating the sample with high-energy electrons.
Claim 13
Independent Claim
98 words
A method for measuring the surface resistance of superconducting materials which comprises in combination: irradiating a sample with ionizing radiation in order to induce charge trapping in the insulating phases; heating the irradiated sample to yield luminescence; measuring the integrated luminescence emitted by the sample as a function of sample temperature; and comparing the integrated luminescence with a calibration curve obtained for similar samples of superconducting materials for which the integrated luminescence of each calibration sample is normalized for the mass of the sample and the surface area emitting the luminescence and related to the surface resistance thereof.
Claim 14
Independent Claim
98 words
A method for measuring the surface resistance of superconducting materials which comprises in combination: irradiating a sample with ionizing radiation in order to induce charge trapping in the insulating phases; heating the irradiated sample to yield luminescence; measuring the integrated luminescence emitted by the sample as a function of sample temperature; and comparing the integrated luminescence with a calibration curve obtained for similar samples of superconducting materials for which the integrated luminescence of each calibration sample is normalized for the mass of the sample and the surface area emitting the luminescence and related to the surface resistance thereof.
References Cited (Backward Citations)
US2573245A
Cited
US3317727A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-09 | 1993-04-10 | 1993-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-09 | 1997-04-10 | 1997-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-09 | 2001-04-10 | 2001-10-10 | $7700.00 | Window Closed / Lapsed |