Compact ionization source
A compact ionization source includes first and second electrodes, each having a plurality of fingers that are interdigitated with each other. The spacing between the first and second electrode, preferably less than 1 mm, creates a large electric field when a potential is applied across the first and second electrodes. The large electric field creates an ionization volume between the fingers of the first and second electrode and ionizes a portion of the molecules occupying the ionization volume. The interdigitated fingers of the first and second electrodes allow for a narrow gap separating the electrodes while presenting a large flow area for ionizing molecules for downstream analysis.
1. An ionization source comprising:
a first electrode having a plurality of fingers;
a second electrode having a plurality of fingers, the plurality of fingers of the second electrode disposed between the plurality of fingers of the first electrode; and
a generator for applying a signal between the first and second electrodes, the signal generating an ionization volume between the first and second electrode; and
a diamond-like coating (DLC) layer deposited on the first and second electrodes wherein the DLC layer comprises n-doped tetrahedral amorphous carbon.
2. The ionization source of claim 1 , wherein a distance between the first electrode and the second electrode is between 100 μm and 1 μm.
3. The ionization source of claim 2 , wherein the distance between the first electrode and the second electrode is between 60 μm and 5 μm.
4. The ionization source of claim 3 , wherein the distance between the first electrode and the second electrode is between 40 μm and 10 μm.
5. The ionization source of claim 1 , further comprising a carbon nanotube layer disposed on a side of the first electrode facing a side of the second electrode.
6. The ionization source of claim 5 , wherein the carbon nanotube layer comprises a plurality of carbon nanotubes characterized by a longitudinal axis, the longitudinal axis parallel to a surface normal of the side of the first electrode.
7. The ionization source of claim 1 , wherein the DLC layer is deposited using a filtered cathodic vacuum arc (FCVA).
8. The ionization source of claim 1 , wherein the gap between the first and second electrodes forms a channel that is serpentine in cross-section.
9. An ionization source comprising:
a first electrode having a plurality of fingers, said electrode appearing comb shaped when seen from above; and
a second electrode having a plurality of fingers, said electrode appearing comb shaped when seen from above, the fingers of the second electrode interdigitated with the fingers of the first electrode with a gap between the first and second electrodes that is serpentine in cross-section;
wherein the first and second comb-shaped electrodes are oriented in a flow stream so that they are transverse to the direction of flow of the stream.
10. The ionization source of claim 9 , further comprising a deflector electrode disposed above and/or below the gap between the first and second electrodes to drive ions from between the electrodes to another location for analysis.
11. The ionization source of claim 9 , further comprising a voltage source which applies a voltage potential across the first and second electrodes.
12. The ionization source of claim 9 , further comprising a carbon nanotube layer disposed on a side of the first electrode facing a side of the second electrode.
13. The ionization source of claim 12 , wherein the carbon nanotube layer comprises a plurality of carbon nanotubes characterized by a longitudinal axis, the longitudinal access parallel to a surface normal of the side of the first electrode.
14. An ionization source comprising:
a first electrode having a plurality of substantially parallel planar fingers interconnected at one end; and
a second electrode having a plurality of substantially parallel planar fingers interconnected at one end, the fingers of the second electrode interdigitated with the fingers of the first electrode with a gap between the first and second electrodes;
wherein the first and second electrodes are oriented in a flow stream so that they are transverse to the direction of flow of the stream.
15. The ionization source of claim 14 , further comprising a deflector electrode disposed above and/or below the first and second electrodes to drive ions from between the electrodes to another location for analysis.
16. The ionization source of claim 14 , further comprising a voltage source which applies a voltage potential across the first and second electrodes.
17. The ionization source of claim 14 , further comprising a carbon nanotube layer disposed on a side of the first electrode facing a side of the second electrode.
18. The ionization source of claim 17 , wherein the carbon nanotube layer comprises a plurality of carbon nanotubes characterized by a longitudinal axis, the longitudinal access parallel to a surface normal of the side of the first electrode.