Development and characterization of an electrostatic quadrupole extraction lens for mass spectrometry

A new ion optical element for mass spectrometry has been developed to increase ion-beam transmission into the high-vacuum region of a mass spectrometer. The optic, termed the electrostatic quadrupole extraction lens (EQEL), incorporates quadrupole-like focusing fields into a conventional extraction element. These fields have been established by purposefully positioning openings in an extraction optic and surrounding the optic with a solid, cylindrical barrel unit. Modeling of the EQEL optic shows several regions of high ion beam transmission while, experimentally, the EQEL provides a 35-fold improvement over a conventional extraction optic when used with a glow discharge Mattauch-Herzog geometry mass spectrograph.