Systems and methods for ion mobility control
The invention provides, in various embodiments, systems and methods relating to controlling ion behavior in an ion-based analysis system.
1. A system for controlling ion behavior for ion-based chemical analysis, said system comprising:
a flow path for a flow of ions, an ion source coupled to said flow path, an ion filter including electrodes separated by an analytical gap for generating an ion filter field in said flow path for filtering said flow of ions in said flow path, and
a control structure for controlling ion behavior in said flow path, wherein ions are separated according to species, said separation reflecting ion-mobility-based behavior of said ions in said filter field, wherein said control structure is at least partially conducting, having at least some capacity to conduct a charge.
2. The system of claim 1 , wherein said control structure is for generating an influencing field that influences said flow of ions in said device.
3. The system of claim 1 , wherein said control structure governs ion flow in said flow path to control local effects that impact ion behavior in the analytical field.
4. The system of claim 1 , wherein said control structure includes an influencing source that influences the analytical environment within said analyzer.
5. The system of claim 4 , wherein said control structure governs ion flow activity for at least one of focusing, trapping, confining, translating, steering, selecting, filtering, detecting and redirecting ions in said flow path.
6. The system of claim 4 , wherein said control structure further comprises a plurality of control electrodes forming facing control arrays, said control arrays being addressable to control motion of ions in said flow path.
7. The system of claim 1 , wherein said control structure is separated from said filter.
8. The system of claim 1 , wherein said control structure performs multiple control functions, including ion filtering.
9. The system of claim 1 , wherein said system is a DMS system and is operated as at least one of a spectrometer, filter, detector, and separator based on ion behavior in said filter field.
10. The system of claim 1 , wherein said system is operated to determine the time of flight of ions passing along said flow path.
11. The system of claim 1 , wherein said control structure includes a charge-dissipating control material in said flow path, wherein said control material enables control of charge buildup in said flow path.
12. The system of claim 1 , further including an active control structure for controlling field artifacts in said flow path.
13. The system of claim 12 , wherein said artifacts include fringing effects at the edges of said filter electrodes.
14. The system of claim 12 , wherein said control structure includes a grid array of electrodes, wherein said array is driven to selectively control ion flow in said flow path.
15. The system of claim 1 , wherein said control structure includes a control array of electrodes for affecting ion behavior in said flow path.
16. The system of claim 14 , wherein said array is driven to provide a non-uniform field in said flow path.
17. The system of claim 16 , wherein said non-uniform field is ion-focusing in said flow path.
18. The system of claim 17 further including a spacer, wherein said filter electrodes are formed on substrates and said filter electrodes are spaced apart by said spacer for setting said analytical gap and for forming an enclosed flow path.
19. The system of claim 1 , wherein said filter field is non-uniform and ion-focusing in said flow path.
20. A system for controlling ion behavior for ion-based chemical analysis, said system comprising:
a flow path for a flow of ions, an ion source coupled to said flow path, an ion filter including electrodes separated by an analytical gap for generating an ion filter field in said flow path for filtering said flow of ions in said flow path,
a control structure for controlling ion behavior in said flow path, wherein ions are separated according to species, said separation reflecting ion-mobility-based behavior of said ions in said filter field, and
a spacer, wherein said filter electrodes are formed on respective substrates and said filter electrodes are spaced apart by said spacer for setting said analytical gap and for forming an enclosed flow path, said spacer being partially conducting.
21. The system of claim 20 , wherein said spacer is partially conducting and insulated from said substrates.
22. A system for controlling ion behavior for ion-based chemical analysis, said system comprising:
a flow path for a flow of ions, an ion source coupled to said flow path, an ion filter including electrodes separated by an analytical gap for generating an ion filter field in said flow path for filtering said flow of ions in said flow path,
a control structure for controlling ion behavior in said flow path, wherein ions are separated according to species, said separation reflecting ion-mobility-based behavior of said ions in said filter field, and
a spacer, wherein said filter electrodes are formed on respective substrates and said filter electrodes are spaced apart by said spacer for setting said analytical gap and for forming an enclosed flow path, said control structure being formed on said substrates.
23. The system of claim 1 , wherein said control structure is charge dissipating.
24. The system of claim 1 , wherein said control structure is charge dissipating and further including a wall structure extending along said flow path for containing said flow of ions, said control structure being recessed from said wall structure.
25. A system for controlling ion behavior for ion-based chemical analysis, said system comprising:
a flow path for a flow of ions, an ion source coupled to said flow path, an ion filter including electrodes separated by an analytical gap for generating an ion filter field in said flow path for filtering said flow of ions in said flow path,
a control structure for controlling ion behavior in said flow path, wherein ions are separated according to species, said separation reflecting ion-mobility-based behavior of said ions in said filter field, and
a plurality of flow channels joining said flow path, further including a plurality of control structures, said plurality of control structures each being formed as the mouth of a respective said flow channel, wherein said plurality of control structures reduce the likelihood of charge build-up in said flow path.
26. The system of claim 1 , wherein said control structure includes a plurality of separated conductive electrodes whose combined effect is to be partially conducting relative to said filter electrodes, wherein said plurality is isolated from said filter electrodes for dissipating charge build-up in said flow path.
27. The system of claim 1 , wherein said control structure includes partially conducting material selected from the group consisting of: semiconductor material and resistive paint, ceramic, doped glass and ion-implanted material.
28. The system of claim 27 , wherein resistance of said material is in the range of 10 2 ≦ohms/square≦10 14 .
29. The system of claim 28 , wherein said range is within:
10 7 ≦ohms/square≦10 11 .
30. A method for controlling ion behavior in an ion-based analysis system, said method including the steps of:
providing a flow path for a flow of ions,
generating an ion filter field in said flow path for filtering said flow of ions,
controlling behavior of ions in said flow of ions,
separating ions in said flow of ions according to species, said separating being based on ion-mobility-based behavior of said ions in said filter field, and
controlling actively a control structure for reducing field artifacts in said flow path, said control structure being recessed to reduce the effect of charge buildup upon said flow of ions.
31. The method of claim 30 , including the step of generating an influencing field that influences said flow of ions to be separated.
32. The method of claim 31 , wherein said influencing includes taking an action selected from the group consisting of focusing, trapping, confining, translating, selecting, and filtering ions in said flow path.
33. The method of claim 32 , wherein said filter field is a compensated asymmetric high-low varying RF filter field.
34. The method of claim 33 , wherein said system is operated to determine the time of flight of ions passing along said flow path.
35. The method of claim 30 , including the step of providing said control structure with a charge-dissipating control material in said flow path, wherein said control material is coupled to said system to prevent charge buildup in said flow path.
36. The method of claim 30 , wherein said control structure includes an array of electrodes.
37. The method of claim 30 , wherein said control structure is recessed to minimize the effect of charge buildup upon said flow of ions.
38. The method of claim 30 , wherein said recess is formed by the mouth of a flow channel.
39. The method of claim 38 , wherein said flow channel introduces a gas flow into said flow of ions for concentrating said flow of ions.
40. The method of claim 39 including the step of introducing a plurality of gas flows into said flow of ions for concentrating said flow of ions in said flow path.
41. The method of claim 36 including the step of isolating said array from said filter electrodes.
42. The method of claim 36 , wherein said array is partially conducting and is coupled to said system for dissipating charge build-up in said flow path.