Patent ID: 9117617
Filing Date: 2015-08-25
Classification: H01J

Abstract:
1. An ion source, comprising: a body comprising an ionization chamber and a sample inlet leading into the ionization chamber, the ionization chamber comprising a first end and a second end, and having a length along a source axis from the first end to the second end; a magnet assembly surrounding the body and configured for generating an axial magnetic field in the ionization chamber; an electron source positioned at the first end and comprising a thermionic cathode and an electron reflector, the electron source configured for accelerating an electron beam through the ionization chamber along the source axis; and a lens assembly comprising an extractor positioned at the second end, a first lens element outside the ionization chamber and spaced from the extractor along the source axis, and a second lens element spaced from the first lens element along the source axis, wherein the extractor is configured for directing an ion beam out from the ionization chamber along the source axis, the first lens element is configured for reflecting the electron beam toward the electron source, and the second lens element is configured for transmitting higher energy ions while reflecting lower energy ions toward the first lens element.