US3733491A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photomultiplier tube circuit
Assignee: Eastman Kodak Co
•
Filing: 1971-07-23
•
Granted: 1973-05-15
•
Expires: 1991-07-23
Abstract
Abstract A voltage difference equal to the sum of the voltage differences appearing between the cathode and first dynode, and between the last dynode and ground of a photomultiplier tube is subtracted from the cathode-to-ground voltage difference of a photomultiplier tube. Optical density is calculated by producing the logarithm of the quotient signal so produced.
Inventors
- 👤 F Holland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:37
CPC Classifications
H; H01; H01J; H01J43/00; H01J43/04; H01J43/30; G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/27
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
159 words
In a circuit having: a. a photomultiplier tube, b. voltage divider means for applying voltage differences between pairs of successive dynodes of the photomultiplier tube, and between the cathode and first dynode thereof, and between the ground and last dynode of the photomultiplier tube, the improvement: wherein the voltage divider means includes voltage regulator means for providing at least saturation level voltages between the cathode and first dynode and between the last dynode of the photomultiplier tube and ground, and wherein said circuit includes: 1. means for producing a correction voltage substantially equal to the sum of the voltages across said cathode and first dynode and across said last dynode and ground, and 2. means for receiving the voltage across the said voltage divider means and said correction voltage for subtracting the correction voltage from said voltage across said voltage divider means, thereby to produce a voltage equal to the voltage appearing across the dynodes of the photomultiplier tube.
Claim 2
Dependent Claim
159 words
In a circuit having: a. a photomultiplier tube, b. voltage divider means for applying voltage differences between pairs of successive dynodes of the photomultiplier tube, and between the cathode and first dynode thereof, and between the ground and last dynode of the photomultiplier tube, the improvement: wherein the voltage divider means includes voltage regulator means for providing at least saturation level voltages between the cathode and first dynode and between the last dynode of the photomultiplier tube and ground, and wherein said circuit includes: 1. means for producing a correction voltage substantially equal to the sum of the voltages across said cathode and first dynode and across said last dynode and ground, and 2. means for receiving the voltage across the said voltage divider means and said correction voltage for subtracting the correction voltage from said voltage across said voltage divider means, thereby to produce a voltage equal to the voltage appearing across the dynodes of the photomultiplier tube.
Claim 3
Dependent Claim
45 words
means for receiving the voltage across the said voltage divider means and said correction voltage for subtracting the correction voltage from said voltage across said voltage divider means, thereby to produce a voltage equal to the voltage appearing across the dynodes of the photomultiplier tube.
Claim 4
Dependent Claim
45 words
means for receiving the voltage across the said voltage divider means and said correction voltage for subtracting the correction voltage from said voltage across said voltage divider means, thereby to produce a voltage equal to the voltage appearing across the dynodes of the photomultiplier tube.
Claim 5
Dependent Claim
13 words
The apparatus of claim 1 wherein said voltage regulator means are zener diodes.
Claim 6
Dependent Claim
77 words
The circuit of claim 1 including: a. means for adjusting the voltage applied across said voltage divider means to maintain constant the anode current of said photomultiplier tube irrespective of the flux received by said photomultiplier tube, and b. means for converting the signal output of said means for subtracting voltages into a signal representing the logarithm of such signal, said logarithmic signal being linearly related to the logarithm of the flux received by said photomultiplier tube.
Claim 7
Dependent Claim
16 words
The circuit of claim 3 including means for converting said logarithmic signal into a visual display.
Claim 8
Dependent Claim
15 words
The circuit of claim 4 including means for adjusting the zero reference of said meter.
References Cited (Backward Citations)
US2412423A
Cited
US2417023A
Cited
US2492901A
Cited
US2454871A
Cited
US2707238A
Cited
US3571599A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-14 | 1976-11-13 | 1977-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-14 | 1980-11-13 | 1981-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-14 | 1984-11-13 | 1985-05-15 | $7700.00 | Window Closed / Lapsed |