Abstract: A mass spectrometry unit of the present invention includes a mass spectrometry portion that detects ion current values of a gas to be measured according to mass-to-charge ratio, to thereby measure partial pressures of the gas to be measured. The mass spectrometry unit further includes: a control portion for preliminary storing a record of a mass-to-charge ratio of a specific gas that decreases a function of a specific portion of the mass spectrometry unit, in which if an ion current value with the mass-to-charge ratio of the specific gas detected by the mass spectrometry portion is not less than a predetermined value, the control portion outputs a warning signal denoting a functional decrease in the specific portion.

Abstract: A method of controlling a mass spectrometer comprises the steps of: supplying a current to a cathode electrode of an ion source having the cathode electrode and an anode electrode, and ionizing a molecules of a gas to be measured; selecting ions generated in the ion source by mass-to-charge ratio; and detecting an ion current value of the selected ions. When a partial pressure of the gas to be measured is measured based on a detection result of the ion current value, a cathode current is supplied to the cathode electrode such that an emission current flowing between the cathode electrode and the anode electrode becomes constant. When a partial pressure of the gas to be measured is not measured, a constant current having a current value less than that of the cathode current is supplied to the cathode electrode.

Abstract: A method of controlling a mass spectrometer comprises the steps of: supplying a current to a cathode electrode of an ion source having the cathode electrode and an anode electrode, and ionizing a molecules of a gas to be measured; selecting ions generated in the ion source by mass-to-charge ratio; and detecting an ion current value of the selected ions. When a partial pressure of the gas to be measured is measured based on a detection result of the ion current value, a cathode current is supplied to the cathode electrode such that an emission current flowing between the cathode electrode and the anode electrode becomes constant. When a partial pressure of the gas to be measured is not measured, a constant current having a current value less than that of the cathode current is supplied to the cathode electrode.

Abstract: A mass spectrometry unit of the present invention includes a mass spectrometry portion that detects ion current values of a gas to be measured according to mass-to-charge ratio, to thereby measure partial pressures of the gas to be measured. The mass spectrometry unit further includes: a control portion for preliminary storing a record of a mass-to-charge ratio of a specific gas that decreases a function of a specific portion of the mass spectrometry unit, in which if an ion current value with the mass-to-charge ratio of the specific gas detected by the mass spectrometry portion is not less than a predetermined value, the control portion outputs a warning signal denoting a functional decrease in the specific portion.

Abstract: A method of controlling a mass spectrometer comprises the steps of: supplying a current to a cathode electrode of an ion source having the cathode electrode and an anode electrode, and ionizing a molecules of a gas to be measured; selecting ions generated in the ion source by mass-to-charge ratio; and detecting an ion current value of the selected ions. When a partial pressure of the gas to be measured is measured based on a detection result of the ion current value, a cathode current is supplied to the cathode electrode such that an emission current flowing between the cathode electrode and the anode electrode becomes constant. When a partial pressure of the gas to be measured is not measured, a constant current having a current value less than that of the cathode current is supplied to the cathode electrode.