Multireflection time-of-flight mass spectrometer

Patent metadata

Field	Value
Publication number	US-9620350-B2
Application number	US-201615131912-A
Country	US
Kind code	B2
Filing date	Apr 18, 2016
Priority date	Dec 21, 2007
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

A method of reflecting ions in a multireflection time of flight mass spectrometer is disclosed. The method includes guiding ions toward an ion mirror having multiple electrodes, and applying a voltage to the ion mirror electrodes to create an electric field that causes the mean trajectory of the ions to intersect a plane of symmetry of the ion mirror and to exit the ion mirror, wherein the ion are spatially focussed by the mirror to a first location and temporally focused to a second location different from the first location. Apparatus for carrying out the method is also disclosed.

First claim

The invention claimed is:

1. A multireflection time of flight mass spectrometer (MR TOF MS) comprising:
a primary ion mirror arrangement ( 10 ) including a first primary ion mirror ( 10 a ) which has electrodes that define a cross section with a first, minor axis of the first primary ion mirror which lies generally in a direction of shift of ions and a second, major transverse axis of the first primary ion mirror, each axis orthogonal to a longitudinal axis of the first primary ion mirror ( 10 a ), wherein the first primary ion mirror ( 10 a ) extends a greater distance in its major axis than in its minor axis and the longitudinal axis being defined generally in the direction of TOF spread of ions in the first primary ion mirror ( 10 a ), the first primary ion mirror ( 10 a ) having a first plane of symmetry that contains the longitudinal axis of the first primary ion mirror ( 10 a ) and major axis of the first primary ion mirror ( 10 a );
a secondary ion mirror arrangement ( 20 ) including a first secondary ion mirror ( 20 ) which has electrodes defining a cross section with a first, minor axis of the first secondary ion mirror and a second, major axis of the first secondary ion mirror, each orthogonal to a longitudinal axis of the first secondary ion mirror ( 20 ) again defined generally in the direction of TOF separation of ions in the first secondary ion mirror;
means for supplying a voltage to the electrodes of the primary and secondary ion mirror arrangements ( 10 , 20 ) so as to establish electric fields therein such that the electric field in the first primary ion mirror ( 10 a ) is configured to cause:
(a) ions to drift in a direction parallel to the minor axis of the first primary ion mirror ( 10 a );
(b) the mean trajectory of ions to intercept the first plane of symmetry of the first primary ion mirror ( 10 a );
(c) spatial focusing of the ions in a direction parallel to the direction of shift of ions in the mirror; and

an ion guiding means ( 30 , 150 ) configured to introduce ions from an ion acceleration region into the MR TOF MS in a direction which is non-parallel to the first plane of symmetry of the first primary ion mirror ( 10 a ) so as to cause ions so introduced to reflect between the primary and secondary ion mirror arrangements at least once prior to exiting them for subsequent processing or detection.

2. The multireflection time of flight mass spectrometer (MR TOF MS) of claim 1 wherein the primary ion mirror arrangement ( 10 ) comprises a second primary ion mirror ( 10 b ) configured to receive ions reflected out of the secondary ion mirror arrangement ( 20 ), and wherein the means for supplying a voltage to the electrodes of the primary ion mirror arrangement ( 10 ) is so as to establish electric fields therein such that the electric field in the second primary ion mirror ( 10 b ) is configured to cause ions to drift in a direction parallel to the minor axis of the second primary ion mirror ( 10 b ).

3. The multireflection time of flight mass spectrometer (MR TOF MS) of claim 2 wherein the primary ion mirror arrangement ( 10 ) comprises a third primary ion mirror ( 10 c ) and a fourth primary ion mirror ( 10 d ) each configured to receive ions reflected out of the secondary ion mirror arrangement ( 20 ), and wherein the means for supplying a voltage to the electrodes of the primary ion mirror arrangement ( 10 ) is so as to establish electric fields therein such that the electric fields in the third and fourth primary ion mirrors ( 10 c , 10 d ) are configured to cause ions to drift in a direction parallel to the minor axis of the third primary ion mirror ( 10 c ) and the fourth primary ion mirror ( 10 d ).

4. The multireflection time of flight mass spectrometer (MR TOF MS) of claim 2 wherein the secondary ion mirror arrangement ( 20 ) comprises a second secondary ion mirror configured to receive ions reflected out of the second primary ion mirror ( 10 b ).

5. The multireflection time of flight mass spectrometer (MR TOF MS) of claim 4 wherein the secondary ion mirror arrangement ( 20 ) comprises a third secondary ion mirror and a fourth secondary ion mirror and wherein the ion mirrors are configured such that ions flow through the ion mirrors in the following order: first primary ion mirror ( 10 a ), first secondary ion mirror, second primary ion mirror ( 10 b ), second secondary ion mirror, third primary ion mirror ( 10 c ), third secondary ion mirror, fourth primary ion mirror ( 10 d ), and fourth secondary ion mirror.

6. The multireflection time of flight mass spectrometer (MR TOF MS) of claim 2 wherein the major axis of each of the first and second primary ion mirrors ( 10 a , 10 b ) is:
(a) mutually parallel; and
(b) orthogonal to the major axis of the secondary ion mirror.

7. The multireflection time of flight mass spectrometer (MR TOF MS) of claim 1 wherein the major axis of the first primary ion mirror ( 10 a ) is parallel to the major axis of the first secondary ion mirror and offset in the direction of the minor axis of the primary ion mirror arrangement ( 10 ).

8. The multireflection time of flight mass spectrometer (MR TOF MS) of claim 1 wherein the major axis of the first primary ion mirror ( 10 a ) is orthogonal to the major axis of the first secondary ion mirror ( 20 ).

9. The multireflection time of flight mass spectrometer (MR TOF MS) of claim 5 wherein the ion mirrors are in a generally circular arrangement oriented towards a common center, the circular arrangement comprising a first semicircle and a second semicircle, wherein all primary ion mirrors occupy the first semicircle and all secondary ion mirrors occupy a second semicircle, the multireflection time of flight mass spectrometer comprising a circular lens at the center of the circular arrangement.

10. The multireflection time of flight mass spectrometer (MR TOF MS) of claim 1 wherein all of the primary ion mirrors ( 10 a , 10 b , 10 c , 10 d ) and/or all of the secondary ion mirrors have a cross section which has one of the following shapes:
(a) rectangular; and
(b) elliptical.

11. The multireflection time of flight mass spectrometer (MR TOF MS) of claim 1 wherein the ion guiding means comprises a linear trap ( 150 ).

12. The multireflection time of flight mass spectrometer (MR TOF MS) of claim 1 and further comprising one or more deflectors ( 40 , 43 ) configured to straighten the ion trajectories on their entrance into the secondary ion mirror as they exit a final primary ion mirror ( 10 d ) of the primary ion mirror arrangement ( 10 ) such that ions reflect in the secondary ion mirror ( 20 ) and return to the final primary ion mirror ( 10 d ) of the primary ion mirror arrangement ( 10 ) exactly on the incoming trajectory.

Assignees

• Thermo Fisher Scient (Bremen) Gmbh

Inventors

• Makarov Alexander A
• Grinfeld Dmitry E
• Monastyrskiy Mikhail A

Classifications

• H01J49/061

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

• H01J49/406 Primary

  with multiple reflections · CPC title

• H01J49/405

  characterised by the reflectron, e.g. curved field, electrode shapes · CPC title

• H01J49/40

  Time-of-flight spectrometers (H01J49/36 takes precedence) · CPC title

• H01J49/06 Primary

  Electron- or ion-optical arrangements · CPC title