Plasma cleaning for mass spectrometers

Patent metadata

Field	Value
Publication number	US-9589775-B2
Application number	US-201514814147-A
Country	US
Kind code	B2
Filing date	Jul 30, 2015
Priority date	Aug 1, 2014
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

A mass spectrometry (MS) system may be cleaned by generating plasma and contacting an internal surface of the system to be cleaned with the plasma. The system may be switched between operating in an analytical mode and in a cleaning mode. In the analytical mode a sample is analyzed, and plasma may or may not be actively generated. In the cleaning mode the plasma is actively generated, and the sample may or may not be analyzed.

First claim

What is claimed is:

1. A mass spectrometry (MS) system, comprising:
an ion source configured for producing analyte ions;
a chamber;
an internal surface located in the chamber;
a plasma source configured for generating or flowing plasma in the chamber effective for cleaning the internal surface, the plasma source comprising a microwave power source, a plasma outlet, and a housing communicating with the chamber via the plasma outlet, wherein the plasma source is configured for applying a microwave power sufficient to generate plasma both in the housing and in the chamber; and
a controller configured for switching between operating the MS system in an analytical mode and a cleaning mode, wherein:
during the analytical mode, the controller is configured for producing analytical data from the ion measurement signals; and
during the cleaning mode the controller is configured for operating the plasma source to generate or flow the plasma in the chamber.

2. The MS system of claim 1 , wherein the plasma source is configured for generating plasma in pulses comprising alternating on and off states of the plasma or alternating high-energy and low-energy states of the plasma.

3. A mass spectrometry (MS) system, comprising:
an ion source configured for producing analyte ions;
a chamber;
an internal surface located in the chamber;
a plasma source configured for generating or flowing plasma in the chamber effective for cleaning the internal surface;
a plasma guide device configured for guiding charged particles of the plasma in the chamber, wherein the plasma guide device comprises a magnet, an electrode, or both a magnet and an electrode; and
a controller configured for switching between operating the MS system in an analytical mode and a cleaning mode, wherein:
during the analytical mode, the controller is configured for producing analytical data from the ion measurement signals; and
during the cleaning mode the controller is configured for operating the plasma source to generate or flow the plasma in the chamber.

4. The MS system of claim 1 , comprising a magnet configured for applying a static magnetic field to a plasma generation region proximate to the internal surface, and a microwave radiation source configured for directing microwave energy to the plasma generation region.

5. The MS system of claim 4 , wherein the magnet and the microwave radiation source are configured for operating at parameters effective for generating plasma in the plasma generation region by electron cyclotron resonance (ECR) excitation.

6. The MS system of claim 4 , wherein the microwave radiation source comprises a patch antenna or a device configured for generating a right-hand circularly polarized electric field in the plasma generation region.

7. The MS system of claim 1 , wherein the plasma source comprises a slot antenna configured for directing microwave radiation into the chamber.

8. The MS system of claim 1 , wherein the controller is configured for determining whether to switch between operating in the analytical mode and in the cleaning mode based on analytical data produced during the analytical mode, during the cleaning mode, or during both the analytical mode and the cleaning mode.

9. The MS system of claim 1 , wherein the controller is configured for:
during the analytical mode, operating the plasma source at a low microwave power sufficient to generate plasma in the housing, wherein the plasma flows into the chamber via the plasma outlet; and
during the cleaning mode, operating the plasma source at a high microwave power sufficient to generate plasma both in the housing and in the chamber.

10. A mass spectrometry (MS) system, comprising:
an ion source configured for producing analyte ions;
a chamber;
an internal surface located in the chamber;
a movement device configured for moving the internal surface toward and away from the chamber;
a plasma source configured for generating or flowing plasma in the chamber effective for cleaning the internal surface; and
a controller configured for switching between operating the MS system in an analytical mode and a cleaning mode, wherein:
during the analytical mode, the controller is configured for producing analytical data from the ion measurement signals; and
during the cleaning mode the controller is configured for operating the plasma source to generate or flow the plasma in the chamber.

11. The MS system of claim 10 , wherein:
the chamber comprises a first chamber and a second chamber;
the plasma source is configured for generating or flowing plasma in the second chamber; and
the movement device is configured for moving the internal surface from the first chamber to the second chamber while switching to the cleaning mode.

12. The MS system of claim 11 , wherein the internal surface is a first internal surface, and further comprising a second internal surface, wherein:
the movement device is configured for moving the first internal surface from the first chamber to the second chamber, and moving the second internal surface from the second chamber to the first chamber, such that the first internal surface is subjected to plasma cleaning while the second internal surface is operated to process analyte ions; and
the movement device is configured for moving the first internal surface from the second chamber to the first chamber, and moving the second internal surface from the first chamber to the second chamber, such that the second internal surface is subjected to plasma cleaning while the first internal surface is operated to process analyte ions.

13. The MS system of claim 10 , wherein the controller is configured for moving the internal surface into proximity with the plasma.

14. The MS system of claim 13 , wherein the controller is configured for, before moving the internal surface into proximity with the plasma, operating the internal surface to process analyte ions.

15. The MS system of claim 3 , wherein the controller is configured for:
during the analytical mode, applying a low-voltage bias to the internal surface effective for guiding the analyte ions; and
during the cleaning mode, applying a high-voltage bias to the internal surface effective for accelerating charged particles of the plasma into contact with the internal surface.

16. The MS system of claim 3 , wherein the plasma guide device is configured for applying a magnetic field, an electric field, or both a magnetic field and an electric field, with a field strength and field orientation effective for accelerating charged particles of the plasma into contact with the internal surface.

17. The MS system of claim 3 , comprising an additional magnet configured for applying a static magnetic field near an inside surface of the chamber effective for reflecting charged species of the plasma away from the inside surface.

Assignees

• Agilent Technologies Inc

Inventors

• Perelman Gershon
• Denning Mark
• Vahidpour Mehrnoosh
• Partridge Guthrie

Classifications

• H01J49/00 Primary

  Particle spectrometers or separator tubes · CPC title