Mass spectrometer for trace gas leak detection with suppression of undesired ions
AssigneeVarian, Inc.
InventorsJ. Daniel Geist, Jeffrey Diep, Peter Williams, Charles W. Perkins
Life of this patent
Estimating the term…
Abstract
Mass spectrometers for trace gas leak detection and methods for operating mass spectrometers are provided. The mass spectrometer includes an ion source to ionize trace gases, such as helium, a magnet to deflect the ions and a detector to detect the deflected ions. The ion source includes an electron source, such a filament. The method includes operating the electron source at an electron accelerating potential relative to an ionization chamber sufficient to ionize the trace gas but insufficient to form undesired ions, such as triply charged carbon.
Claims8
A method of operating a mass spectrometer, including an ion source to ionize helium, a magnet to deflect the helium ions and a detector to detect the deflected helium ions, the ion source including a filament, the method comprising:
- operating the filament at an electron accelerating potential relative to an ionization chamber sufficient to ionize the helium but insufficient to form triply charged carbon, comprising operating the filament to generate electrons having kinetic energies of 25 to 92 electron volts within the ionization chamber.
A mass spectrometer comprising:
- an ion source including an electron source;
- a power supply to operate the electron source at a voltage relative to an ionization chamber sufficient to produce helium ions but insufficient to produce triply charged carbon, wherein the power supply is configured to operate the electron source to produce electrons having kinetic energies within the ionization chamber of 25 to 92 electron volts;
- a magnet to deflect the helium ions;
- and
- a detector to detect the deflected helium ions.
Dependencies are inferred from the claim text.