Quasi-Planar Multi-Reflecting Time-of-Flight Mass Spectrometer

Patent metadata

Field	Value
Publication number	US-2016358764-A1
Application number	US-201615244931-A
Country	US
Kind code	A1
Filing date	Aug 23, 2016
Priority date	Jul 16, 2008
Publication date	Dec 8, 2016
Grant date	—

Abstract

A multi-reflecting, time-of-flight (MR-TOF) mass spectrometer including two quasi-planar electrostatic ion mirrors extended along drill direction (Z) and formed of parallel electrodes, separated by a field free region. The MR-TOF includes a pulsed ion source to release ion packets at a small angle to X-direction which is orthogonal to the drill direction Z. Ion packets are reflected between ion mirrors and drill along the drift direction. The mirrors are arranged to provide time-of-flight focusing ion packets on the receiver. The MR-TOF mirrors provide spatial focusing M the Y-direction orthogonal to both drift direction Z and on injection direction X. In a preferred embodiment, at least one mirror has a feature providing periodic spatial focusing of ion packets in the drift Z-direction.

First claim

1 . A multi-reflecting time-of-flight mass spectrometer comprising:
two quasi-planar electrostatic ion mirrors extended along a drift direction (Z) and formed of parallel electrodes, wherein said mirrors are separated by a field free field-free region; a pulsed ion source to release ion packets at small angle to an X direction which is orthogonal to the drift direction Z, such that the ion packets are reflected between the ion mirrors and drift along the drift direction; a receiver to receive the ion packets; wherein said mirrors are positioned to provide time-of-flight focusing on said receiver and provide spatial focusing in a Y-direction orthogonal to both the drift direction Z and the ion injection direction X; and wherein at least one of said mirrors has a periodic feature providing modulation of electrostatic field along the drift Z-direction for the purpose of periodic spatial focusing of the ion packets in the Z-direction.

2 . The apparatus as defined in claim 1 and further including at least one end deflector for reverting ion path in the drift direction.

3 . The apparatus as defined in claim 1 and further including at least one isochronous curved interface between said pulsed ion source and said receiver.

4 . The apparatus as defined in claim 1 and further including at least two lenses in the field free field-free region.

5 . The apparatus as defined in claim 1 , wherein at least one of said mirrors comprises at least four electrodes with at least one electrode having attracting potential applied thereto to provide said time-of-flight focusing and said spatial focusing in the Y-direction.

6 . The apparatus as defined in claim 1 , wherein said periodic feature comprises at least one mirror electrode with the opening varying in height in the Y-direction.

7 . The apparatus as defined in claim 1 , wherein said periodic feature comprises at least one mirror electrode with the varying width along the X direction.

8 . The apparatus as defined in claim 1 , wherein said periodic feature is a set of periodic lenses incorporated into the internal electrode of at least one of said mirrors.

9 . The apparatus as defined in claim 1 , wherein said periodic feature comprises a set of auxiliary electrodes incorporated into at least one mirror electrode and wherein a potential of the auxiliary electrodes varies periodically in the Z-direction.

10 . The apparatus as defined in claim 1 , wherein said periodic feature has a period equal N*ΔZ/2, where N is an integer number and ΔZ is an advance in the drift direction of said ion jigsaw trajectory per reflection.

11 . The apparatus as defined in claim 1 , wherein said periodic feature has a period equal to integer number of periods of said jigsaw trajectory.

12 . A method of time-of-flight analysis comprising the steps of:
forming packets of analyzed ions; passing ion packets between two parallel and quasi-planar ion mirrors extended along a drift Z-direction while retaining relatively small velocity component of the ion packets along the Z-direction such that the ion packets move along a jigsaw ion trajectory; receiving ions at a receiver; focusing the ion packets in time and spatially focused in direction Y; and spatially and periodically modulating an electrostatic field within at least one mirror in order to provide for spatial focusing of the ion packets along the Z-direction.

13 . The method as defined in claim 12 and further comprising a step of reverting the direction of ion drift at the edges of an analyzer.

14 . The method as defined in claim 12 and further comprising injection of ion packets via a curved isochronous interface.

15 . The method as defined in claim 12 and further comprising spatial focusing of ion packets within a drift space between said mirrors by at least two lenses.

16 . The method as defined in claim 12 , wherein said step of periodically modulating electrostatic field within at least one of said mirrors comprises a step of spatial modulation of the shape of at least one mirror electrode.

17 . The method as defined in claim 12 , wherein said step of periodically modulating electrostatic field within at least one of said ion mirrors comprises a step of introducing periodic field of auxiliary electrodes.

18 . The method as defined in claim 12 , wherein the period of said modulation equals to N*ΔZ/2, where N is an integer number and ΔZ is an advance in the drift direction of said ion jigsaw trajectory per reflection.

19 . The method as defined in claim 12 , wherein said step of forming ion packets includes step of ion accumulation of ions coming from a continuous ion source.

20 . The method as defined in claim 12 , wherein the strength of periodic focusing in the Z-direction is adjustable.

Assignees

• Leco Corp

Inventors

• Verentchikov Anatoli N
• Yavor Mikhail I

Classifications

• H01J49/22

  Electrostatic deflection · CPC title

• H01J49/0031

  Step by step routines describing the use of the apparatus (H01J49/0081 takes precedence) · CPC title

• H01J49/406 Primary

  with multiple reflections · CPC title