MASS SPECTROMETER

PURPOSE:To permit the analysis of materials from the material sticking to the surface of a sample to the material contained in the sample by providing a primary ion accelerating power source which can be changed over to a low voltage and high voltage to a primary ion source part. CONSTITUTION:This consists of the primary ion source part (1-8), secondary ion source part (9-13), analyzing part (15-17) and detecting part (110-114). The gas supplied from a cylinder 6 to the inside of a chamber 3 is ionized by the electrons emitted from a filament 1 and the ions are accelerated by the voltage of the primary ion accelerating power source 7 so as to be plunged into a chamber 9. The ions collide against the sample on a sample base 10 and ionize the same is the chamber 9. The sample ions are accelerated by the acceleration voltage of a secondary ion accelerating power source 13 and are subjected to mass dispersion by a magnetic field 16. The secondary ions past a collector slit 17 are received in a collector 110 and are recorded as mass spectra in a recorder 113. The primary ion acceleration voltage is changed at every scanning of the magnetic field 16 by feeding a signal from a pulse power source 114 in the above-mentioned manner, by which the inconvenience in ionization is eliminated.