Particle charge spectrometer

An airflow through a tube is used to guide a charged particle through the tube. A detector may be used to detect charge passing through the tube on the particle. The movement of the particle through the tube may be used to both detect its charge and size.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will now be described in detail with reference to the accompanying drawings, wherein:

FIG. 1 shows a basic layout of the particle sizing device;

FIGS. 2

a and

2

b shows an oscilloscope trace of a particle trace;

FIG. 3 shows a graph of determination of particle size as compared with transition time; and

FIG. 4 shows a block diagram of the electronics layout.

1. A device comprising:

2. A device as in claim 1, wherein said detector produces an output signal indicative of a charge of said particle, and a movement of said particle, and determines size of said particle from said movement of said particle.

3. A device as in claim 1, wherein said airflow producing part includes an air pump.

4. A device as in claim 1, wherein said particle position constraining part includes a capillary tube.

5. A device as in claim 1, wherein said detector includes a Faraday cage.

6. A device as in claim 5, wherein said detector includes a Faraday cage cylindrical electrode.

7. A device as in claim 5, further comprising a transistor, connected to said Faraday cage, and driven by an output of said Faraday cage to produce said signal.

8. A device as in claim 1, wherein said particle constraining part is a glass capillary.

9. A device as in claim 1, wherein said particle constraining part is a capillary having a diameter less than 10 mm.

10. A method, comprising:

11. A method as in claim 10, wherein said producing comprises analyzing a signal produced by said sensing to determine a size of the particle.

12. A method as in claim 10, wherein said using comprises confining said charged particle within a dielectric capillary.

13. A method as in claim 10, wherein said using comprises confining said charged particle within a capillary having a diameter less than ten mm and formed of glass.

14. A method as in claim 10, wherein said sensing comprises using a Faraday cage to sense charge of this charged particle as a function of time.

15. A method as in claim 14 wherein said using a Faraday cage comprises using a cylindrical electrode Faraday cage.

16. A method, comprising:

17. A method as in claim 16, wherein said forcing comprises applying a known airflow to said charged particle.

18. A method as in claim 16, further comprising detecting a size of said charged particle based on a waveform detected by said detecting.

19. A method as in claim 16, wherein said dielectric capillary has a diameter less than one mm.

20. A method as in claim 19, wherein said dielectric capillary is formed of glass.

21. A method, comprising: