Patent ID: 8173069

Claim:
An ion analyzing apparatus comprising: a first sensor; a second sensor; at least one counter electrode having openings, the at least one counter electrode being positioned so as to substantially surround the first sensor and the second sensor; a positive bias generating circuit coupled to the first sensor; and a negative bias generating circuit coupled to the second sensor; each of the first sensor and the second sensor includes a quartz crystal and a pair of electrodes positioned on surfaces of the quartz crystal; one of the pair of electrodes of the first sensor is coupled to the positive bias generating circuit, and one of the pair of electrodes of the second sensor is coupled to the negative bias generating circuit; a first oscillation circuit coupled to the pair of electrodes of the first sensor; a second oscillation circuit coupled to the pair of electrodes of the second sensor; and a frequency measuring circuit configured to measure a change in frequency of the first oscillation circuit or the second oscillation circuit.