Method and instrument for mass analyzing samples with a quistor

US4975577A · kind A · utility

Assignee

• The United States of America as represented by the Secretary of the Army · US

Inventors

• Jochen Franzen · Bremen, DE
• Reemt-Holger Gabling · Stuhr, DE
• Gerhard Heinen · Tarmstedt, DE
• Gerhard Weiss · Ludwigshafen, DE

Key dates

• Filing date: Dec 29, 1989
• Grant date: Dec 4, 1990
• Expiry date: Dec 29, 2009

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01J49/429
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A method for the measurement of mass spectra by three dimensional quadrup fields (QUISTORs) is presented, in which the ions are mass-to-charge selectively ejected by a selected nonlinear resonance effect in an inharmonic QUISTOR. In order to enhance scan speed and mass resolution, the ejection of a single kind of ions can be confined to a very small time interval, either by the generation of ions within a small volume outside the field center, or by an excitation of the secular amplitudes by an additional RF voltage across the end electrodes, shortly before the ions encounter the sum resonance condition. An instrument for this method is described.