US3900731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for stabilizing the gain of a photomultiplier
Assignee: Schlumberger Technology Corp
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Filing: 1973-01-22
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Granted: 1975-08-19
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Expires: 1993-01-22
Abstract
Abstract A photomultiplier gain stabilization system maintains the mean output current of a photomultiplier at a constant level by compensating its variations through a modification of the illumination of its photocathode. The photocathode is coupled to a photoemissive diode, supplied with a current representative of the difference between the value of the mean current of the photomultiplier anode and a reference current value equal to at least the maximum value of the anode current.
Inventors
- 👤 Philippe Chevalier
- 👤 Bronislav Seeman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:35
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/36; G01T1/40; G01T1/16; G01T1/20; G01T1/208; H; H01; H01J; H01J43/00; H01J43/04; H01J43/30
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
63 words
The method of stabilizing the gain of a photomultiplier comprising, providing a source of reference current, continuously detecting variations in the mean or average anode current of the photomultiplier as compared with said reference current, illuminating the photocathode of the photomultiplier with an auxiliary light source, and continuously modifying said illumination in response to said continuously detected variations to stabilize said photomultiplier gain.
Claim 2
Independent Claim
63 words
The method of stabilizing the gain of a photomultiplier comprising, providing a source of reference current, continuously detecting variations in the mean or average anode current of the photomultiplier as compared with said reference current, illuminating the photocathode of the photomultiplier with an auxiliary light source, and continuously modifying said illumination in response to said continuously detected variations to stabilize said photomultiplier gain.
Claim 3
Independent Claim
112 words
A system for stabilizing the gain of a photomultiplier having at least an anode and a photocathode comprising, a light source of variable intensity operative to illuminate said photocathode, means for providing a source of reference current of a selected value, means for determining the mean or average anode current of the photomultiplier, and means coupled to said light source, said anode current determining means, and said source of reference current for continuously varying the intensity of illumination of said light source in response to the difference between the mean or average value of the anode current of said photomultiplier and said selected value of reference current to stabilize said photomultiplier gain.
Claim 4
Independent Claim
112 words
A system for stabilizing the gain of a photomultiplier having at least an anode and a photocathode comprising, a light source of variable intensity operative to illuminate said photocathode, means for providing a source of reference current of a selected value, means for determining the mean or average anode current of the photomultiplier, and means coupled to said light source, said anode current determining means, and said source of reference current for continuously varying the intensity of illumination of said light source in response to the difference between the mean or average value of the anode current of said photomultiplier and said selected value of reference current to stabilize said photomultiplier gain.
Claim 5
Dependent Claim
16 words
A system according to claim 2 wherein said light source is optically coupled to said photocathode.
Claim 6
Dependent Claim
14 words
A system according to claim 2 wherein said light source is a photoemissive diode.
Claim 7
Dependent Claim
21 words
A system according to claim 4 wherein said photoemissive diode is embedded in a light conducting member disposed adjacent said photocathode.
Claim 8
Dependent Claim
30 words
A system according to claim 2, wherein said light source intensity varying means is operative in response to the difference between the mean anode current and said selected reference current.
Claim 9
Dependent Claim
30 words
A system according to claim 2, wherein said light source intenisty varying mEans is operative in response to the difference between the average anode current and said selected reference current.
Claim 10
Independent Claim
136 words
A system for stabilizing the gain of a photomultiplier having at least an anode and a photocathode comprising, a light source of variable intensity operative to illuminate said photocathode, means for providing a source of reference current to a selected value, means for determining the mean or average anode current of the photomultiplier, and means coupled to said light source and said anode current determining means for comparing the mean or average anode current of said photomultiplier and said selected value of reference current and operative continuously to generate a control signal representative of the difference between said mean or average anode current and said selected value of reference current for varying the intensity of illumination of said light source in response to the changes in the value of said difference to stabilize said photomultiplier gain.
Claim 11
Independent Claim
136 words
A system for stabilizing the gain of a photomultiplier having at least an anode and a photocathode comprising, a light source of variable intensity operative to illuminate said photocathode, means for providing a source of reference current to a selected value, means for determining the mean or average anode current of the photomultiplier, and means coupled to said light source and said anode current determining means for comparing the mean or average anode current of said photomultiplier and said selected value of reference current and operative continuously to generate a control signal representative of the difference between said mean or average anode current and said selected value of reference current for varying the intensity of illumination of said light source in response to the changes in the value of said difference to stabilize said photomultiplier gain.
Claim 12
Dependent Claim
20 words
The system of claim 8 including current integrating means connected between the anode of said photomultiplier and said comparing means.
Claim 13
Dependent Claim
16 words
The system of claim 8 wherein said light source of variable intensity is a photoemissive diode.
Claim 14
Dependent Claim
24 words
The system of claim 8 wherein the selected value of the reference current is at least the maximum value of the mean anode current.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |