Apparatus and method for inhibiting ionization source filament failure
US9159542B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 17, 2012 |
| Grant date | Oct 13, 2015 |
| Priority date | — |
| Expiry date | Feb 17, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/06308
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An ion source apparatus for a mass spectrometer comprises a refractory metal filament operable to provide a flow of electrons by thermionic emission; an electrical current source electrically coupled to the filament for heating the filament; a vacuum chamber enclosing the filament; an ionization volume within the vacuum chamber capable of receiving the flow of electrons; a source of an oxygen-providing gas or gases; a restrictive fluidic coupling to the source of oxygen-providing gas or gases; and a gas conduit fluidically coupled to the restrictive fluidic coupling, the restrictive fluidic coupling and conduit operable to provide a flow of the oxygen-providing gas or gases into the vacuum chamber so as to maintain a partial pressure of said gas or gases within the vacuum chamber that is sufficiently high so as to inhibit the otherwise formation of a carbonaceous growth on the filament in the presence of a gaseous carbon-containing material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.