Electron Impact Quadrupole Mass Spectrometry (EI-QMS)

A key challenge in many high-mass quantum experiments is post-ionization of the originally neutral molecular beam. For covalently bound and stable molecules up to about 16,000 amu we often opt for electron impact ionization, followed by mass spectrometry in an Extrel Quadrupole Spectrometer (1:2000 resolution).

Even though electron impact suffers typically from a low ionization yield (often smaller than 10-4), the continuous operation and non-resonant (universal) applicability is a distinguishing feature of this technology.

This method has been used in many TLI and all KDTLI experiments, so far.