Ionization balance device with shielded capacitor circuit for ion balance measurements and adjustments

摘要

In one example, this disclosure describes a circuit and techniques that may be used to measure the ion balance in an ionization balance device (10). The described circuit comprises a capacitor (22) that includes two conductors (23, 24), wherein a first one (23) of the conductors is exposed to the output of the ionization device, and the second one (24) of the conductors is shielded from the output of the ionization device. The first conductor may accumulate charge so as to quantify the output of the ionization balance device. A switch (29) may be used to discharge the first conductor at periodic intervals in order to measure the accumulated charge on the first conductor, and signal processing may be performed on this discharge measurement in order to generate feedback that can be used to control and adjust the output of an ion source.

主权项

1. An ionization balance device for use with a stream of ions flowing away from the ionization balance device and in a direction generally toward a target area, wherein the stream of ions is comprised of a plurality of ions, the ionization balance device comprising:
an ion source configured to emit the plurality of ions; a capacitor including a first conductor and a second conductor,
wherein the first conductor is configured to be exposed to at least a portion of the plurality of ions; andwherein the second conductor is configured to be shielded from the at least a portion of the plurality of ions and to output a first signal; and a signal conditioning circuit coupled to the second conductor of the capacitor, wherein the signal conditioning circuit is configured to receive the first signal and to output a second signal indicative of ion balance based, at least in part, upon the first signal, and wherein the signal conditioning circuit includes at least one peak and hold detector.