An inexpensive, bakeable quadrupole mass spectrometer

The design, construction and operation of a simple and inexpensive quadrupole mass spectrometer is described. The spectrometer covers the mass range 1 to 100 A.U. and the resolving power of the instrument is variable up to about 100. The use of a machinable ceramic material to support the electrodes enables the spectrometer to be baked for outgassing purposes and to be operated over a wide range of temperature. Although the spectrometer described is tuned manually, the instrument has been used in conjunction with a sawtooth waveform generator to obtain an automatic mass scan with a scan period of about 0·1 s.