Patent ID: 9508534
Filing Date: 2016-11-29
CPC Classification: H01J

Claim Text:
1. A method of operating a mass spectrometer, comprising: supplying a quantity of ions to an ion detector, the ion detector including a conversion dynode operating in a first polarity and an electron multiplier; calibrating the gain of the electron multiplier to determine a first set of calibration parameters; calculating a second set of calibration parameters for the electron multiplier from the first set of calibration parameters, the second set of calibration parameters being for a second polarity of the conversion dynode; configuring the ion detector to operate at the second polarity based on the second set of calibration parameters; calibrating the electron multiplier when the ion detector is operating in the second polarity using the second set of calculated calibration parameters as a starting point; supplying ions of the second polarity to the mass spectrometer; and detecting an ion at a particular mass to charge ratio using the ion detector.