MASS SPECTROMETER

PURPOSE:To enable efficient measurement by controlling an emitter current controller so as to increase or decrease the emitter current corresponding to the amount of the fragment peak. CONSTITUTION:An emitter 10 applied with a sample is holded on the probe 2 and inserted in the source 1. After the initiation of the measurement, as the emitter current is increased gradually through the emitter current controller 3, ions are generated in the ion source 1 and introduced into the analyzing tube 4 then dispersed according to their mass by the magnetic field of the magnetic device 5 and transported to the collector 6 to be displayed as the fragment peak on the display monitor 7. On the other hand, this signal is inputted to the data processor 8 through the interface 9. The data processor 8 decides whether the total summation of these signals is over a specified value or not, and when the total summation is over the said value the processor controls the emitter current so as to slow down the increasing rate of the current or to keep the current constant. Thereby the measurement can be carried out in high efficiency.