Patent ID: 7491931

Claim:
An ion source for a mass analyzer comprising: a first electrode; a second electrode spaced apart from the first electrode; and a power source electrically coupled to one or more of the first electrode and the second electrode, the power source comprising: a power supply circuit having at least one output node coupled through a switch to at least one of the first electrode and the second electrode, the power supply circuit supplying an electric potential to at least one of the first electrode or the second electrode to establish an electric field at a predetermined time; and a feedback circuit responsive to a DC component and an AC component of an output voltage supplied by the power supply to produce a feedback signal on an output node of the feedback circuit representative of at least one of: (a) a value of the output voltage prior to a charge transfer from a capacitor associated with the power supply to at least one of the first electrode and the second electrode; (b) a value of the output voltage during the charge transfer from the capacitor associated with the power supply to at least one of the first electrode and the second electrode; and (c) a value of the output voltage after the charge transfer from the capacitor associated with the power supply to at least one of the sample support or the first electrode.