Patent ID: 6967485

Claim:
A process for operating a detector comprising: (a) generating a measurement signal from ionization that arises when exposing sample gas to output from a lamp operated at an initial level of a drive power; (b) determining a concentration of ionizable gases using the measurement signal generated in step (a) and a mapping of measurement signal levels to concentrations of the ionizable gases; (c) changing the drive power to a new level in response to a trigger event that indicates that intensity of the output of the lamp may have changed; (d) generating the measurement signal from ionization that arises when exposing sample gas to the output from the lamp operated at the new level; (e) determining a concentration of the ionizable gases using the measurement signal generated in step (d) and the mapping of measurement signal levels to concentrations of the ionizable gases; and repeating steps (c), (d), and (e) at intervals during operation of the detector, wherein repeating steps (c), (d), and (e) occurs between consecutive calibrations of the detector, wherein each calibration of the detector comprises: (a1) selecting a coarse level from a plurality of coarse levels for the drive power; (b1) applying the drive power at the selected coarse level to the lamp; (c1) recording the measurement signal generated from ionization that arises from exposing a gas mixture to the output from the lamp at the selected coarse level; (d1) repeating steps (a1), (b1), and (c1) until the measurement signal for each of the coarse levels have been recorded; and (e1) setting the initial level of the drive power to the coarse level that corresponds to a desired mapping of measurement signal levels to concentrations of ionizable gases.