Scientific and teaching apparatus and instruments, particularly spectrometers, analysing apparatus in the nature of residual gas analyzers, mass spectrometers, time of flight mass spectrometers, ion mobility spectrometer; Inductively coupled plasma mass spectrometers; Electron-ionization spectrometers; Ion sources for scientific measuring and teaching apparatus and instruments, namely, spectrometers, analysing apparatus in the nature of residual gas analyzers, mass spectrometers, time of flig...