Driving a mass spectrometer ion trap or mass filter
First Claim
1. A system for driving a mass spectrometer ion trap or mass filter, comprising:
- a frequency and amplitude programmable RF generator producing an RF signal;
an RF gain stage receiving the RF signal and generating an amplified RF signal;
sense circuitry generating a sense signal proportional to a supply current delivered to the RF gain stage;
a transformer having a primary coupled to an output of the RF gain stage and a secondary coupled to form a tank circuit with a capacitance of the mass spectrometer ion trap or mass filter; and
power circuitry receiving the sense signal and generating a feedback control signal to the RF generator that adjusts a frequency of the RF generator to decrease a power level of the RF signal supplied to the RE gain stage.
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Accused Products
Abstract
A radio frequency (RF) drive system and method for driving the ion trap or mass filter of a mass spectrometer has a programmable RF frequency source coupled to a RF gain stage. The RF gain stage is transformer coupled to a tank circuit formed with the ion trap or mass filter. The power of the RF gain stage driving the ion trap or mass filter is measured using a sensing circuit and a power circuit. A feedback value is generated by the power circuit that is used to adjust the RF frequency source. The frequency of the RF frequency source is adjusted until the power of the RF gain stage is at a minimum level. The frequency value setting the minimum power is used to operate the RF drive system at the resonance frequency of the tank circuit formed with the transformer secondary inductance and the ion trap or mass filter capacitance. Driving a mass spectrometer mass selection element this way results in the lower power consumption, an inherently filtered clean drive signal, smaller size, and reduced electromagnetic emissions.
445 Citations
13 Claims
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1. A system for driving a mass spectrometer ion trap or mass filter, comprising:
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a frequency and amplitude programmable RF generator producing an RF signal; an RF gain stage receiving the RF signal and generating an amplified RF signal; sense circuitry generating a sense signal proportional to a supply current delivered to the RF gain stage; a transformer having a primary coupled to an output of the RF gain stage and a secondary coupled to form a tank circuit with a capacitance of the mass spectrometer ion trap or mass filter; and power circuitry receiving the sense signal and generating a feedback control signal to the RF generator that adjusts a frequency of the RF generator to decrease a power level of the RF signal supplied to the RE gain stage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A radio frequency (RF) driver system for driving a mass spectrometer ion trap or mass filter comprising:
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a transformer having a secondary coupled to the mass spectrometer ion trap or mass filter; a RF gain stage having an output coupled to a primary of the transformer; and a frequency and amplitude programmable RF source generating a signal coupled to an input of the RF gain stage, circuitry of the programmable RF source configured so that the frequency of the programmable RF source is dynamically adjusted to decrease to a minimum a power level supplied to the RF gain stage when driving the mass spectrometer ion trap or mass filter.
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13. A method of operating a mass spectrometer comprising:
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driving the mass spectrometer with a signal in order to trap ions therein, wherein circuitry for driving the mass spectrometer comprises an RF gain stage coupled to the mass spectrometer via a transformer, and wherein an RF generator is coupled to an input of the RF gain stage; monitoring a power level supplied to the RF gain stage while driving the mass spectrometer and generating a feedback signal proportional to the power level; and coupling the feedback signal to adjust a frequency of the RF generator to decrease the power level supplied to the RF gain stage when driving the mass spectrometer.
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Specification