Time of flight mass spectrometer

• US 20060192110A1
• Filed: 02/14/2006
• Published: 08/31/2006
• Est. Priority Date: 02/15/2005
• Status: Active Grant

• Current Assignee: Shimadzu Corporation
• Original Assignee: Shimadzu Corporation
• Inventors: Yamaguchi, Shinichi
• Granted Patent: US 7,355,168 B2
• Time in Patent Office: Days
• US Class Current: 250/288
• CPC Class Codes: H01J 49/282 using electrostatic analysers
• CPC Class Codes: H01J 49/408 with multiple changes of direction, e.g. by using electric or magnetic sectors, closed-loop time-of-flight

Abstract

The present invention provides a time of flight mass spectrometer having an ion optics forming a multi-turn track, which is capable of time-focusing the ions while allowing the multi-turn track to be configured in an unlimited and highly variable manner. In a specific form of the invention, a reflector 9 is provided on the flight path between the position where the ions leave the loop orbit P and the ion detector 10 located outside the loop orbit P, and the condition of the electric field generated by the reflector 9 is appropriately determined. Thus, even if the ions cannot be well time-focused by the ion optics 2 creating the sector-shaped electric fields 4 and 7, it is possible to compensate the time-focusing performance with the reflector 9 to achieve a good performance of time-focusing of the ion throughout the overall system wherein the ions leave the ion source 1 and finally reach the ion detector 10. Thereby, the ions can reach the ion detector 10 at approximately the same time even if the ions having the same mass number have different levels of energy at the moment they leave the ion source 1.

Claims

1. A time of flight mass spectrometer, comprising:

an electric field generator for creating a loop type or reciprocal type of multi-turn track for causing ions to travel in substantially a same path one or more times;

an ion source located on or out of the multi-turn track at which the ions begin to fly;

an ion detector located out of the multi-turn track for detecting the ions that have traveled in the multi-turn track one or more times and left the multi-turn track; and

a compensator, located between a position at which the ions leave the multi-turn track and the ion detector or between the ion source and a position at which the ions enter the multi-turn track, for compensating the focusing of ions so as to achieve the time-focusing of the ions throughout an overall flight path along which the ions travel after leaving the ion source until reaching the ion detector.

2. The time of flight mass spectrometer according to claim 1, wherein the compensator is a reflector for creating an electric field that reflects incoming ions.

3. The time of flight mass spectrometer according to claim 1, wherein the compensator is an electrode assembly for creating a sector-shaped electric field.

4. The time of flight mass spectrometer according to claim 1, wherein the multi-turn track is an “

8”

shaped loop orbit.

5. The time of flight mass spectrometer according to claim 1, wherein the ion source is located on the multi-turn track.

6. The time of flight mass spectrometer according to claim 5, wherein the ion source is a three-dimensional quadrupole ion trap composed of a couple of end cap electrodes and a ring electrode, where the end cap electrodes include an entrance-side end cap electrode with an injecting perforation and an exit-side end cap electrode with an ejecting perforation, and the ions enter the ion trap through the injecting perforation and then exit through the ejecting perforation while repeatedly flying along the loop orbit P.