Ei Ionization - Ametek FlarePro User Manual

Figure 1-1.
Ionizer
components.
As a cloud of electrons accelerates towards the Ionizer Body, the
electrons collide with the sample in the center of the ion volume and
create ions.
Once the ions are formed, they are extracted from the ion region and
focused toward the quadrupole Mass Filter by a difference in potential.
Lens 1 has an applied negative voltage that, due to a difference in
electrostatic potential, attracts the newly formed ions, passing them
through Lens 2. Lens 2, in turn, focuses the electrons into the
quadrupole.

EI Ionization

When a single electron is removed, a positive ion is created – this is
referred to as a molecular ion. When the bombarding electrons cause the
molecular bonds to break, fragment ions form. This ionization process is
known as electron impact ionization (EI).
Operation of the mass spectrometer depends on maintaining low vacuum
pressures. These pressures take into account not only the operational
pressures of the mass spectrometer, but also the pressures of the sample
system environments.
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Overview 1-3