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US3649907A
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Method and apparatus for mapping the sensitivity of the face of a photodetector specifically a pmt
Assignee: National Aeronautics and Space Administration
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Filing: 1970-03-11
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Granted: 1972-03-14
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Expires: 1990-03-11
Abstract
Abstract Apparatus and technique for obtaining color-coded area sensitivity maps of photomultiplier tubes. First and second oscilloscopes are driven in synchronism to produce rasters on their faces. The raster of the first oscilloscope is optically imaged on the face of the photomultiplier tube being checked. The output of the photomultiplier is applied to a detector which produces an output if and only if the output of the photomultiplier is between two voltages set into the detector. The output of the detector intensity modulates the second oscilloscope and a color camera takes a picture of the face of the second oscilloscope through a color filter. Different voltages are set into the detector and the camera takes another picture through a different color filter. This procedure is continued which results in a color-coded area sensitivity map of the photomultiplier tube. In an alternate embodiment of the invention a color television is used in place of the second oscilloscope, the camera and the color filter. In this embodiment a different detector is needed for each color.
Inventors
- 👤 Otto Youngbluth Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:19
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/24; G01R31/25; G01R31/252
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
145 words
Apparatus for mapping the sensitivity of the face of a photodetector comprising: first and second oscilloscopes; means for driving said first and second oscilloscopes to obtain synchronized rasters on their faces; means for optically imaging the raster on the face of said first oscilloscope on the face of said photodetector; detector means, having first and second voltages set into it, connected to the output of said photodetector for producing a voltage if, and only if, the output of said photodetector after amplification is between said first and second voltages; and means for connecting the output of said detector means to said second oscilloscope to intensity modulate the raster on its face whereby the modulated area of the raster on the face of said second oscilloscope corresponds to the area on the face of said photodetector having a sensitivity determined by said first and second voltages.
Claim 2
Dependent Claim
145 words
Apparatus for mapping the sensitivity of the face of a photodetector comprising: first and second oscilloscopes; means for driving said first and second oscilloscopes to obtain synchronized rasters on their faces; means for optically imaging the raster on the face of said first oscilloscope on the face of said photodetector; detector means, having first and second voltages set into it, connected to the output of said photodetector for producing a voltage if, and only if, the output of said photodetector after amplification is between said first and second voltages; and means for connecting the output of said detector means to said second oscilloscope to intensity modulate the raster on its face whereby the modulated area of the raster on the face of said second oscilloscope corresponds to the area on the face of said photodetector having a sensitivity determined by said first and second voltages.
Claim 3
Dependent Claim
66 words
Apparatus according to claim 1 including a color camera for taking a picture of the face of said second oscilloscope and a colored filter located between said camera and the face of said second oscilloscope whereby the picture taken by said camera is a colored area corresponding to the area of sensitivity on the face of said photodetector represented by the color of said colored filter.
Claim 4
Dependent Claim
49 words
Apparatus according to claim 2 wherein said detector means includes means for changing said first and second voltages, said colored filter is interchangeable with other colored filters, and said camera is a multiexposure camera whereby a color-coded contour sensitivity mapping of the face of said photodetector can be made.
Claim 5
Dependent Claim
128 words
Apparatus according to claim 1 wherein said detector means includes a first circuit connected to said first voltage for producing a third voltage while the output of said photodetector exceeds said first voltage and for producing a fourth voltage while said first voltage exceeds the output of said photodetector; a second circuit connected to said second voltage for producing said third voltage while the output of said photodetector exceeds said second voltage and for producing said fourth voltage while said second voltage exceeds the output of said photodetector; and a difference amplifier connected to the outputs of said first and second circuits whereby said difference amplifier produces an output if and only if the output of said photodetector is at a level between said first and second voltages.
Claim 6
Dependent Claim
143 words
Apparatus for mapping the sensitivity of the face of a photodetector comprising: an oscilloscope; a color television; means for driving said oscilloscope and said color television to obtain synchronized rasters on their faces; means for optically imaging the raster on the face of said oscilloscope on the face of said photodetector; a plurality of detector means with each having first and second voltages set into it and connected to the output of said photodetector for producing a voltage if and only if the output of said photodetector after amplification is between said first and second voltages; and means for connecting the outputs from said plurality of detector means to said color television to produce a different color for each detector means that produces an output signal whereby said color television produces a color-coded mapping of the sensitivity of the face of said photodetector.
Claim 7
Dependent Claim
143 words
Apparatus for mapping the sensitivity of the face of a photodetector comprising: an oscilloscope; a color television; means for driving said oscilloscope and said color television to obtain synchronized rasters on their faces; means for optically imaging the raster on the face of said oscilloscope on the face of said photodetector; a plurality of detector means with each having first and second voltages set into it and connected to the output of said photodetector for producing a voltage if and only if the output of said photodetector after amplification is between said first and second voltages; and means for connecting the outputs from said plurality of detector means to said color television to produce a different color for each detector means that produces an output signal whereby said color television produces a color-coded mapping of the sensitivity of the face of said photodetector.
Claim 8
Dependent Claim
119 words
Method for mapping the sensitivity of the face of a photodetector comprising the steps of: driving first and second oscilloscopes to obtain synchronized rasters on their faces; optically imaging the raster on the face of said first oscilloscope oN the face of said photodetector; producing a voltage if and only if the resulting output of said photodetector is between two preselected values; intensity modulating the raster on the face of second oscilloscope with said produced voltage; and taking a picture of the face of said second oscilloscope through a colored filter whereby the picture taken is a colored area corresponding to the area of sensitivity on the face of said photodetector represented by the color of said colored filter.
Claim 9
Dependent Claim
119 words
Method for mapping the sensitivity of the face of a photodetector comprising the steps of: driving first and second oscilloscopes to obtain synchronized rasters on their faces; optically imaging the raster on the face of said first oscilloscope oN the face of said photodetector; producing a voltage if and only if the resulting output of said photodetector is between two preselected values; intensity modulating the raster on the face of second oscilloscope with said produced voltage; and taking a picture of the face of said second oscilloscope through a colored filter whereby the picture taken is a colored area corresponding to the area of sensitivity on the face of said photodetector represented by the color of said colored filter.
Claim 10
Dependent Claim
27 words
Method according to claim 6 including the additional step of changing said two preselected values and the color of said colored filter to obtain a multicolored picture.
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) | 1975-03-14 | 1975-09-13 | 1976-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-14 | 1979-09-13 | 1980-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-14 | 1983-09-13 | 1984-03-14 | $7700.00 | Window Closed / Lapsed |