US 7,022,982 B2 · Ion source frequency feedback device and method

Abstract

An ion source for an analytical instrument is described. The ion source comprises a capillary tip and counter-electrode interface and a feedback loop control device connected to the capillary tip and counter-electrode interface. The feedback loop control device comprises a transimpedance amplifier, a DC de-coupler, a frequency to voltage converter, a controller, and a voltage-controlled high-voltage power supply that provides a tip to counter-electrode voltage to the capillary tip and counter-electrode interface. The feedback loop control device measures the modulation frequency of ionization currents and provides a feedback adjustment of the tip-to-counter-electrode voltage to maintain ionization efficiency.

Claims21

Dependent claims

An ion source for controlling charged molecules in an ion spray, comprising:

a capillary tip having a central longitudinal axis;
a counter-electrode downstream from the capillary tip having a central axis and an aperture along the central axis for receiving ions ejected from the capillary tip;
and
a closed feedback loop for coupling the capillary tip to the counter-electrode and regulating the ion spray produced from the capillary tip,
wherein the closed feedback loop maintains ionization efficiency by measuring a modulation frequency of ionization currents and adjusting a tip to counter-electrode voltage.

2 more elements

Dependencies are inferred from the claim text.

Ion source frequency feedback device and method

Life of this patent

Ion source frequency feedback device and method

Life of this patent

Abstract

Claims21