US3634754A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for linearly measuring electron capture with an electron capture detector
Assignee: Shell USA Inc
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Filing: 1969-06-23
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Granted: 1972-01-11
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Expires: 1989-06-23
Abstract
Abstract Linear response is obtained from an electron capture measuring device by pulsing an electron capture detector at a variable frequency, automatically varying the frequency in accordance with the detector current, measuring the frequency, and using the frequency measurement as the output of the device.
Inventors
- 👤 James E Lovelock
- 👤 Albert J Davies
- 👤 Frank R Ferris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:44
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/62; G01N27/64; G01N27/66; G01T; G01T1/00; G01T1/16; G01T1/185
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
72 words
The method of linearizing the response of an electron capture measuring circuit including electron capture detector means for measuring concentration of electron capture material comprising the steps of: supplying a pulsed current of variable frequency to said electron capture detector means; sensing the detector current; varying said frequency in accordance with said sensed detector current; and providing an indication of said frequency as an indication of concentration of said electron capture material.
Claim 2
Independent Claim
72 words
The method of linearizing the response of an electron capture measuring circuit including electron capture detector means for measuring concentration of electron capture material comprising the steps of: supplying a pulsed current of variable frequency to said electron capture detector means; sensing the detector current; varying said frequency in accordance with said sensed detector current; and providing an indication of said frequency as an indication of concentration of said electron capture material.
Claim 3
Dependent Claim
23 words
The method of claim 1, in which said frequency is varied in such a manner as to maintain said detector current substantially constant.
Claim 4
Dependent Claim
135 words
A measuring circuit in combination with an electron capture detector for measuring a concentration of an electron capture material, comprising pulse generator means of a type suitable for generating voltage pulses at a certain frequency and arranged to supply these pulses to a pair of terminals to which the detector is connected; electrometer means arranged to sense the current supplied to the detector by the said terminals and to produce at its output a signal varying in accordance with the senseD value; means connected to the electrometer output for adjusting the frequency of the pulse generator in response to the electrometer output signal and thereby opposing the influence of variations in the measured concentration on the detector current; and means for measuring said frequency as an indication of the concentration of said electron capture material.
Claim 5
Dependent Claim
135 words
A measuring circuit in combination with an electron capture detector for measuring a concentration of an electron capture material, comprising pulse generator means of a type suitable for generating voltage pulses at a certain frequency and arranged to supply these pulses to a pair of terminals to which the detector is connected; electrometer means arranged to sense the current supplied to the detector by the said terminals and to produce at its output a signal varying in accordance with the senseD value; means connected to the electrometer output for adjusting the frequency of the pulse generator in response to the electrometer output signal and thereby opposing the influence of variations in the measured concentration on the detector current; and means for measuring said frequency as an indication of the concentration of said electron capture material.
Claim 6
Dependent Claim
37 words
Measuring circuit according to claim 3, in which the changes in frequency effected by the means for adjusting the pulse generator frequency substantially compensate for the influence of variations in the measured concentration on the detector current.
Claim 7
Dependent Claim
28 words
Measuring circuit according to claim 3, in which the relationship according to which the pulse generator frequency is adjusted in dependence on the detector current is substantially linear.
Claim 8
Dependent Claim
30 words
Measuring circuit according to claim 5, comprising means for indicating or recording the output signal of said electrometer means, which signal is a measure of the concentration to be determined.
Claim 9
Dependent Claim
18 words
Measuring circuit according to claim 5, comprising means for counting the pulses generated by said pulse generator means.
Claim 10
Dependent Claim
32 words
Measuring circuit according to claim 3, further comprising means for providing an adjustable bias in the relationship according to which the pulse generator frequency is adjusted in dependence on the detector current.
Claim 11
Dependent Claim
69 words
Measuring circuit according to claim 3, in which the output signal of the electrometer means is a variable DC voltage, while the pulse generator means and the means for adjusting the frequency thereof respectively comprise a blocking oscillator and a transistor, the transistor being arranged to control the discharge current of a condenser of the blocking oscillator (and thereby the pulse frequency) in dependence on the electrometer output voltage.
References Cited (Backward Citations)
GB1048513A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |