Multi-reflection mass spectrometer

Patent metadata

Field	Value
Publication number	US-2016005585-A1
Application number	US-201514852466-A
Country	US
Kind code	A1
Filing date	Sep 11, 2015
Priority date	Jan 27, 2012
Publication date	Jan 7, 2016
Grant date	—

Abstract

A multi-reflection mass spectrometer is provided comprising two ion-optical mirrors, each mirror elongated generally along a drift direction (Y), each mirror opposing the other in an X direction, the X direction being orthogonal to Y, characterized in that the mirrors are not a constant distance from each other in the X direction along at least a portion of their lengths in the drift direction. In use, ions are reflected from one opposing mirror to the other a plurality of times while drifting along the drift direction so as to follow a generally zigzag path within the mass spectrometer. The motion of ions along the drift direction is opposed by an electric field resulting from the non-constant distance of the mirrors from each other along at least a portion of their lengths in the drift direction that causes the ions to reverse their direction.

First claim

1 . (canceled)

2 . A method of mass spectrometry comprising the steps of:
injecting ions into a multi-reflection mass spectrometer comprising two ion-optical mirrors, each mirror elongated generally along a drift direction Y, each mirror opposing the other in an X direction, the X direction being orthogonal to Y direction; reflecting the ions from one mirror to the other, generally orthogonally to the drift direction, a plurality of times by turning the ions within each mirror whilst the ions proceed along the drift direction Y, wherein the distance between consecutive points in the X-direction at which the ions turn monotonously changes with Y during at least a part of the motion of the ions along the drift direction; and detecting at least some of the ions during or after their passage through the multi-reflection mass spectrometer.

3 . The method of mass spectrometry of claim 1 in which the multi-reflection mass spectrometer further comprises one or more electrically biased compensation electrodes extending along at least a portion of the drift direction, each electrode being located in or adjacent a space between the mirrors.

4 . The method of mass spectrometry of claim 1 in which ions are injected into the multi-reflection mass spectrometer from one end of the opposing ion-optical mirrors in the drift direction, the ion-optical mirrors being closer together in the X direction along at least a portion of their lengths as they extend in the drift direction away from a location of ion injection.

5 . The method of mass spectrometry of claim 3 in which the ions are turned around after passing along the drift length and proceed back along the drift length towards the location of ion injection.

6 . The method of mass spectrometry of claim 1 in which both mirrors are curved to follow a parabolic shape so as to curve towards each other as they extend in the drift direction.

7 . The method of mass spectrometry of claim 2 in which the one or more compensation electrodes comprises a pair of compensation electrodes, each electrode being located either side of the space between the mirrors, and in which each of the compensation electrodes has a surface having a polynomial profile in the X-Y plane such that the said surfaces extend towards each mirror a greater distance in the regions near one or both ends of the mirrors than in the central region between the ends.

8 . The method of mass spectrometry of claim 2 in which the one or more compensation electrodes comprises a pair of compensation electrodes, each electrode being located either side of the space between the mirrors, and in which each of the compensation electrodes has a surface having a polynomial profile in the X-Y plane such that the surfaces extend towards each mirror a lesser distance in the regions near one or both the ends of the mirrors than in a central region between the ends.

9 . The method of mass spectrometry of claim 2 in which the one or more compensation electrodes comprise a plurality of tubes or compartments located at least partially in a space extending between the opposing mirrors.

10 . The method of mass spectrometry of claim 2 in which the one or more compensation electrodes are electrically biased so as to produce, in at least a portion of a space extending between the opposing mirrors, an electrical potential offset which varies as a function of a distance along a drift length.

11 . The method of mass spectrometry of claim 2 in which the one or more compensation electrodes are electrically biased so as to compensate for at least some time-of-flight aberrations generated by the opposing mirrors.

12 . The method of mass spectrometry of claim 2 in which the one or more compensation electrodes are electrically biased so as to compensate for a time-of-flight shift in the drift direction generated by the opposing mirrors and so as to make a total time-of-flight shift of the system substantially independent of variations of an initial ion beam trajectory inclination angle in a X-Y plane.

13 . The method of mass spectrometry of claim 2 in which the multi-reflection mass spectrometer further comprises one or more additional compensation electrodes extending along a first portion of the drift length, each electrode being located either side of the space extending between the mirrors and being electrically biased, and in which the ions oscillate between the opposing mirrors whilst proceeding along at least some of the first portion of the drift length in the Y direction before being turned around and proceeding back towards a location of ion injection.

14 . The method of mass spectrometry of claim 1 in which the mass spectrometer further comprises one or more lenses or diaphragms located in a space between the mirrors so as to affect a phase-space volume of ions within the mass spectrometer.

15 . The method of mass spectrometry of claim 1 in which at least some ions impinge upon a detector located in a region adjacent an ion injector.

16 . The method of mass spectrometry of claim 14 wherein the detector has a detection surface which is arranged parallel to the drift direction Y.

Assignees

• Thermo Fisher Scient Bremen

Inventors

• Grinfeld Dmitry
• Makarov Alexander

Classifications

• H01J49/061

  Ion deflecting means, e.g. ion gates · CPC title

• H01J49/406 Primary

  with multiple reflections · CPC title

• H01J49/0027

  Methods for using particle spectrometers · CPC title

• H01J49/004

  Combinations of spectrometers, tandem spectrometers, e.g. MS/MS, MSn · CPC title