Mass spectrometer and electric field source for mass spectrometer

1. An electric field source for use in a mass spectrometer, the electric field source comprising:

a substantially cylindrical inner electrode, comprising electrically-isolated conductive segments arranged in tandem, and a substantially cylindrical substrate, wherein the substantially cylindrical substrate is substantially hollow;

a substantially cylindrical outer electrode concentric with the inner electrode, the outer electrode comprising electrically-isolated conductive segments arranged in tandem; and

a voltage source connected to the outer electrode and operative to apply a pattern of voltages to the conductive segments.

2. A electric source as claimed in claim 1 , wherein the pattern of voltages applied to the conductive segments creates a substantially quadro-logarithmic electrical potential between the inner and outer electrodes.

3. An electric field source as claimed in claim 1 , wherein the inner electrode and the outer electrode are both substantially cylindrical.

4. An electric field source as claimed in claim 1 , further comprising a passive electrical component connected between the voltage source and a respective conductive segment of the outer electrode.

5. An electric field source as claimed in claim 1 , wherein the voltage source is connected to the inner electrode is additionally connected to the conductive segments of the inner electrode and is operative to apply a pattern of voltages to the conductive segments of the inner electrode.

6. An electric field source as claimed in claim 1 , wherein the voltage source comprises a multi-channel digital-to-analog converter.

7. An electric field source as claimed in claim 1 , additionally comprising a substantially cylindrical insulating substrate supporting the conductive segments of the outer electrode.

8. An electric field source as claimed in claim 1 , additionally comprising a substantially cylindrical insulating substrate supporting the conductive segments of the inner electrode.

9. A mass spectrometer adapted to dynamically traps ions in an electrostatic field, comprising:

a substantially cylindrical inner electrode, comprising electrically-isolated conductive segments arranged in tandem, and a substantially cylindrical substrate, wherein the substantially cylindrical substrate is substantially hollow;

a substantially cylindrical outer electrode concentric with the inner electrode, the outer electrode comprising electrically-isolated conductive segments arranged in tandem; and

a voltage source connected to the outer electrode and operative to apply a pattern of voltages to the conductive segments;

a spectrum processor adapted to receive signals from at least one of the plurality of conductive segments.

10. A mass spectrometer as claimed in claim 9 , wherein the selectively applied voltage creates a substantially quadro-logarithmic electrical potential between the inner and outer electrodes.

11. A mass spectrometer as claimed in claim 9 , wherein the inner electrode and the outer electrode are both substantially cylindrical.

12. A mass spectrometer as claimed in claim 9 , further comprising a passive electrical component connected between the voltage source and a respective conductive segment of the outer electrode.

13. A mass spectrometer as claimed in claim 9 , wherein the voltage source is connected to the inner electrode is additionally connected to the conductive segments of the inner electrode and is operative to apply a pattern of voltages to the conductive segments of the inner electrode.

14. A mass spectrometer as claimed in claim 9 , wherein the voltage source comprises a multi-channel digital-to-analog converter.

15. A mass spectrometer as claimed in claim 9 , additionally comprising a substantially cylindrical insulating substrate supporting the conductive segments of the outer electrode.

16. A mass spectrometer as claimed in claim 9 , additionally comprising a substantially cylindrical insulating substrate supporting the conductive segments of the inner electrode.

17. A mass spectrometer as claimed in claim 9 , further comprising an amplifier connected to at least one of the plurality of conductive segments of the outer electrode and to the spectrum processor.

18. A mass spectrometer as claimed in claim 17 , wherein the spectrum processor comprises a Fourier Transform spectrum processor.

19. An electric field source for use in a mass spectrometer, the electric field source comprising:

a substantially cylindrical inner electrode, comprising electrically-isolated conductive segments arranged in tandem, and a substantially cylindrical substrate, wherein the substantially cylindrical substrate is substantially hollow;

a substantially cylindrical outer electrode concentric with the inner electrode, the outer electrode comprising electrically-isolated conductive segments arranged in tandem; and

a voltage source connected to the outer electrode, or to the inner electrode, or both, and operative to apply a pattern of voltages to the conductive segments of the inner electrode, or the outer electrode, or both.

20. A mass spectrometer as claimed in claim 19 , additionally comprising a substantially cylindrical insulating substrate supporting the conductive segments of the outer electrode.

21. A mass spectrometer as claimed in claim 19 , additionally comprising a substantially cylindrical insulating substrate supporting the conductive segments of the inner electrode.