Patent US3823315A successfully refreshed from Google Patents.
US3823315A
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US
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Automatic gain method and controller for mass spectrometer
Assignee: AUTOMATED MED SYST
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Filing: 1972-10-30
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Granted: 1974-07-09
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Expires: 1992-10-30
Abstract
Abstract A method and apparatus for analyzing relative abundance of the composition of a sample with a mass spectrometer having an electron multiplier controlled with a high voltage supply. When the sample is a gas mixture, the volume per cent of a gas is analyzed. The all-ion peak signal is repetitively sampled and held to produce an analog output voltage. This output voltage is compared with a reference voltage via an error amplifier in a feedback loop to control the high voltage applied to the electron multiplier so that the all-ion peak signal of the mass spectrometer is maintained a constant.
Inventors
- 👤 M Mosharrafa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:15
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/0027; H01J43/00; H01J43/04; H01J43/30
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
126 words
A method of controlling the sensitivity of a mass spectrometer having an electron multiplier producing ion output signals and a high voltage supply controlling the electron multiplier comprising: measuring a selected ion peak with the electron multiplier to provide an output signal, averaging a sample of said output signal with a time constant representative of the period during which said selected ion peak is measured to provide a sample output signal, comparing the sample output signal with a constant reference voltage by applying said output signal and said reference voltage, to an error amplifier, and controlling the high voltage applied to the electron multiplier with the output of the error amplifier so that the selected ion peak sample output signals of the spectrometer are maintained constant.
Claim 2
Independent Claim
126 words
A method of controlling the sensitivity of a mass spectrometer having an electron multiplier producing ion output signals and a high voltage supply controlling the electron multiplier comprising: measuring a selected ion peak with the electron multiplier to provide an output signal, averaging a sample of said output signal with a time constant representative of the period during which said selected ion peak is measured to provide a sample output signal, comparing the sample output signal with a constant reference voltage by applying said output signal and said reference voltage, to an error amplifier, and controlling the high voltage applied to the electron multiplier with the output of the error amplifier so that the selected ion peak sample output signals of the spectrometer are maintained constant.
Claim 3
Dependent Claim
27 words
The method of claim 1 wherein: the output of the amplifier drives a voltage regulator circuit that controls the power input to the high voltage power supply.
Claim 4
Dependent Claim
22 words
The method of claim 1 wherein: the selected ion peak output signal is the all-ion peak output signal of the electron multiplier.
Claim 5
Dependent Claim
111 words
A means for controlling the sensitivity of a mass spectrometer having an ion source, filter means, an electron multiplier receiving ions from said source, and high voltage power supply means for controlling said electron multiplier, the improvement comprising means for holding and averaging over a period of time a sample of a selected ion peak output signal of the electron multiplier so as to produce a sample output signal, and error amplifier means for receiving the sample output signal and a reference voltage, said amplifier means having an output controlling the high voltage applied to the electron multiplier such that the sample ion output signals of the spectrometer are maintained constant.
Claim 6
Dependent Claim
111 words
A means for controlling the sensitivity of a mass spectrometer having an ion source, filter means, an electron multiplier receiving ions from said source, and high voltage power supply means for controlling said electron multiplier, the improvement comprising means for holding and averaging over a period of time a sample of a selected ion peak output signal of the electron multiplier so as to produce a sample output signal, and error amplifier means for receiving the sample output signal and a reference voltage, said amplifier means having an output controlling the high voltage applied to the electron multiplier such that the sample ion output signals of the spectrometer are maintained constant.
Claim 7
Dependent Claim
30 words
The means of claim 4 including: circuit means for controlling the power input to the high voltage power supply means thereby controlling the high voltage applied to the electron multiplier.
Claim 8
Dependent Claim
109 words
A means for improving the stability of a mass spectrometer having an ion source, electron multiplier producing ion output signals, and high voltage source means supplying high voltage to the electron multiplier comprising: first means for sampling a selected ion output signal of the electron multiplier to provide a sample output signal, and a second means for comparing said sample output signal with a constant reference signal and applying the difference between the sample output signal and reference signal to a closed feedback loop to control the gain of the electron multiplier by controlling the high voltage source means to vary the high voltage applied to said electron multiplier.
Claim 9
Dependent Claim
109 words
A means for improving the stability of a mass spectrometer having an ion source, electron multiplier producing ion output signals, and high voltage source means supplying high voltage to the electron multiplier comprising: first means for sampling a selected ion output signal of the electron multiplier to provide a sample output signal, and a second means for comparing said sample output signal with a constant reference signal and applying the difference between the sample output signal and reference signal to a closed feedback loop to control the gain of the electron multiplier by controlling the high voltage source means to vary the high voltage applied to said electron multiplier.
Claim 10
Dependent Claim
20 words
The means of claim 6 wherein: said first means is an instrument to sample the all-ion peak of a substance.
Claim 11
Dependent Claim
13 words
The means of claim 6 wherein: said second means includes an error amplifier.
Claim 12
Dependent Claim
21 words
The means of claim 6 wherein: said second means includes circuit means for controlling the power input of the mass spectrometer.
Claim 13
Dependent Claim
31 words
The means of claim 6 wherein: said second means includes an error amplifier and circuit means connected to the error amplifier for controlling a high voltage supply for the mass spectrometer.
Claim 14
Dependent Claim
124 words
A mass spectrometer for analyzing relative abundance of the composition of a sample comprising: an ion source, filter means for receiving ions from said ion source, electron multiplier means for receiving ions from said filter means, a high voltage suppLy for controlling the electron multiplier means, means for holding and averaging over a period of time a sample of a selected ion peak output signal of the electron multiplier means thereby producing a sample output signal, and error amplifier means for receiving the sample output signal and a reference voltage, said amplifier means having an output controlling the high voltage supply to vary the high voltage applied to the electron multiplier means so that the sample output signals of the spectrometer are maintained constant.
Claim 15
Dependent Claim
124 words
A mass spectrometer for analyzing relative abundance of the composition of a sample comprising: an ion source, filter means for receiving ions from said ion source, electron multiplier means for receiving ions from said filter means, a high voltage suppLy for controlling the electron multiplier means, means for holding and averaging over a period of time a sample of a selected ion peak output signal of the electron multiplier means thereby producing a sample output signal, and error amplifier means for receiving the sample output signal and a reference voltage, said amplifier means having an output controlling the high voltage supply to vary the high voltage applied to the electron multiplier means so that the sample output signals of the spectrometer are maintained constant.
Claim 16
Dependent Claim
30 words
The mass spectrometer of claim 11 including: circuit means for controlling the power input to the high voltage supply thereby controlling the high voltage applied to the electron multiplier means.
Claim 17
Dependent Claim
14 words
The mass spectrometer of claim 11 wherein: the filter means is a quadrupole filter.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-08 | 1978-01-07 | 1978-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-08 | 1982-01-07 | 1982-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-08 | 1986-01-07 | 1986-07-09 | $7700.00 | Window Closed / Lapsed |