Scientific measuring and teaching apparatus and instruments, in particular spectrometers, analysing apparatus in the nature of residual gas analysers, mass spectrometers, time-of-flight mass spectrometers, ion mobility spectrometers; scientific apparatus, namely, inductively coupled plasma mass spectrometers; scientific apparatus, namely, electronic ionization spectrometers; ion sources for scientific measuring and teaching apparatus and instruments, namely spectrometers, analysing apparatus ...