Patent ID: 8426805
Filing Date: 2013-04-23
Classification: H01J

Abstract:
1. A method for operating a mass spectrometer having an ion volume and an electron source for supplying electrons to the ion volume, the method comprising: (a) performing a tuning or calibration of the mass spectrometer using a tuning standard or a calibration standard provided in the ion volume; (b) selecting an operational characteristic so as to be a function of an ion intensity produced by ionization of an analysis standard comprising the same or a different tuning standard or the same or a different calibration standard provided in the ion volume during a subsequent plurality of analytical runs, wherein the analysis standard is selected so as to include an internal standard that is used to evaluate a target ion having a target mass-to-charge ratio; (c) setting, in response to the tuning or calibration, one or more operating parameters that influence a flow of electrons from the electron source into the ion volume so as to establish a low nominal value for an effective emission current from the electron source into the ion volume such that ions produced from a material in the ion volume in response to electrons correspond to a user-specified fixed level of a sensitivity of the mass spectrometer; and (d) repeatedly performing the steps of: