Orthogonal acceleration time-of-flight mass spectrometer and tuning method for the same

An orthogonal acceleration time-of-flight mass spectrometer, comprising:

• an ion source;
• an orthogonal acceleration electrode configured to deflect a flight direction of ions incident from the ion source;
• a flight-path-defining electrode configured to define a flight path of the ions deflected by the orthogonal acceleration electrode;
• an ion detection section configured to detect an ion after a flight of the ion through the flight path is completed;
• a voltage application section configured to apply a pulse voltage which deflects the flight direction of the ions in a predetermined cycle of time, as well as a standby voltage during other periods of time to the orthogonal acceleration electrode, and a voltage to the flight-path-defining electrode;
• a measurement control section configured to acquire a plurality of mass spectrum data which are different in an intensity of a mass peak and a mass-resolving power in the mass spectrum data by conducting a measurement of a predetermined kind of known ion generated from a predetermined amount of known sample, under a plurality of measurement conditions which differ from each other in a value of the standby voltage applied from the voltage application section to the orthogonal acceleration electrode;
• and
• a score-value calculation section configured to calculate a score value based on a predetermined calculation formula, using the intensity of the mass peak and the mass-resolving power in the mass spectrum data acquired under each of the plurality of measurement conditions.