Title:
【発明の名称】多重極質量分析計における軸方向射出
Document Type and Number:
Japanese Patent JP2002517888
Kind Code:
A
Abstract:
A method of operating a mass spectrometer having an elongated multipole rod set, in which a two dimensional RF field radially contains trapped ions in a mass to charge range of interest, and in which the ions are contained axially by a barrier field on an end lens and to which a low voltage DC is applied. Trapped ions are axially mass selectively ejected by taking advantage of the mixing of the degrees of freedom induced by the fringing fields and other anti-harmonicities in the vicinity of the end lens. Thus, ions can be mass selectively ejected at the exit end at the same time as ions are being admitted into the entrance end of the rod set, thereby taking better advantage of the ion flux from a continuous ion source. The axial mass selective ejection is performed by applying an auxiliary AC voltage to the end lens, or to the rods themselves, or both, and by scanning either the auxiliary AC voltage or the RF voltage on the rod set. Trapped ions can be concentrated near the exit lens by applying an axial field in the direction of the lens, or can be depleted by applying the axial field in the opposite direction. The axial field can be oscillated to dissociate trapped ions.
Inventors:
Hager, james
Application Number:
JP2000552706A
Publication Date:
June 18, 2002
Filing Date:
June 01, 1999
Export Citation:
Assignee:
MDS Incorporated
International Classes:
H01J49/42; (IPC1-7): H01J49/42
Attorney, Agent or Firm:
Seiji Yanagida (1 person outside)