CPC H01J 49/063 (2013.01) [G01N 30/72 (2013.01); G01N 35/00584 (2013.01); H01J 49/24 (2013.01); H01J 49/42 (2013.01); G01N 2030/326 (2013.01); G01N 2030/328 (2013.01)] | 8 Claims |
1. A mass spectrometer comprising:
a first vacuum chamber;
a first communication hole configured to communicate an atmosphere with the first vacuum chamber;
a first vacuum pump configured to evacuate air from the first vacuum chamber;
an atmospheric pressure relating value acquiring unit configured to acquire an atmospheric pressure relating value relating to an atmospheric pressure;
an adjustment unit configured to adjust an effective exhaust velocity of the first vacuum pump; and
a controller configured to control the adjustment unit,
wherein: the controller acquires the atmospheric pressure relating value and controls the adjustment unit such that a pressure of the first vacuum chamber is a predetermined reference value corresponding to the atmospheric pressure relating value; and
the atmospheric pressure relating value is a value indicating an atmospheric pressure.
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