Ion source frequency feedback device and method

摘要

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.