Time of flight tubes and methods of using them

1. A time of flight tube assembly comprising:

an inner tube comprising an effective thickness and sized and arranged to couple to and support a reflectron assembly inside the inner tube, the inner tube comprising a conductive material disposed on an inner surface of the inner tube, the conductive material present in an effective amount to provide a field free region for ions when the conductive material is charged;

an outer tube surrounding the inner tube, the outer tube effective to insulate the inner tube and electrically isolate the inner tube;

an air gap between the inner tube and the outer tube, wherein the outer tube is coupled to the inner tube through blocks to permit removal of the outer tube and inner tube together as a unit; and

a reflectron assembly coupled to the inner tube, the reflectron assembly comprising a lens stack.

2. The time of flight tube assembly of claim 1 , in which the inner tube comprises a material with a coefficient of thermal expansion that is effective to maintain a substantially constant height of the inner tube during operation of the time of flight tube.

3. The time of flight tube assembly of claim 2 , in which the coefficient of thermal expansion of the material is effective to permit longitudinal expansion of the inner tube by about two microns or less.

4. The time of flight tube assembly of claim 1 , in which the conductive material on the inner surface of the inner tube comprises a coated conductive material.

5. The time of flight tube assembly of claim 1 , in which the outer surface of the inner tube is non-conductive.

6. The time of flight tube assembly of claim 1 , further comprising a cap coupled to the inner tube.

7. The time of flight tube assembly of claim 6 , in which the cap is effective to seal the inner tube to permit vacuum operation of the time of flight tube.

8. The time of flight tube assembly of claim 7 , in which the cap is configured to receive a gasket to seal the cap to the inner tube.

9. The time of flight tube assembly of claim 1 , further comprising a conductive element electrically coupled to the conductive material disposed on the inner surface of the inner tube.

10. The time of flight tube assembly of claim 9 , further comprising a second conductive element disposed on the inner surface of the inner tube, in which the second conductive element is electrically coupled to the first conductive element.

11. The time of flight tube assembly of claim 10 , further comprising a contact assembly configured to contact the first conductive element to electrically couple the first conductive element to a power source.

12. The time of flight tube assembly of claim 1 , further comprising at least one heater coupled to an outer surface of the inner tube.

13. The time of flight tube assembly of claim 12 , further comprising a temperature sensor coupled to the outer surface of the inner tube.

14. The time of flight tube assembly of claim 13 , in which the inner tube comprises a material with a coefficient of thermal expansion that is effective to maintain a substantially constant height of the inner tube during operation of the time of flight tube at a temperature provided by the at least one heater.

15. The time of flight tube assembly of claim 14 , in which the coefficient of thermal expansion of the material is effective to permit longitudinal expansion of the inner tube by about two microns or less at the temperature provided by the at least one heater.

16. The time of flight tube assembly of claim 1 , further comprising a plurality of longitudinal rods coupled to the inner tube.

17. A time of flight tube assembly comprising:

an inner tube comprising an effective thickness and sized and arranged to couple to and support a reflectron assembly inside the inner tube, the inner tube comprising a conductive material disposed on an inner surface of the inner tube, the conductive material present in an effective amount to provide a field free region for ions when the conductive material is charged;

an outer tube surrounding the inner tube, the outer tube effective to insulate the inner tube and electrically isolate the inner tube;

an air gap between the inner tube and the outer tube; and

a reflectron assembly coupled to the inner tube, the reflectron assembly comprising a lens stack, in which each lens of the lens stack of the reflectron assembly comprises a planar conductive body comprising a first surface and a second surface, the planar body comprising an aperture between a first side and a second side of the first surface of the planar body, the planar body further comprising a plurality of conductors spanning the aperture from the first side to the second side of the first surface of the planar body, each of the plurality of conductors attached to the planar body at the first side and at the second side of the first surface, in which the plurality of conductors are each substantially parallel to each other and are positioned in the same plane.

18. The time of flight tube assembly of claim 17 , further comprising a plurality of transverse rods coupled to each lens of the lens stack.

19. A time of flight tube assembly comprising:

an inner tube comprising an effective thickness and sized and arranged to couple to and support a reflectron assembly inside the inner tube, the inner tube comprising a conductive material disposed on an inner surface of the inner tube, the conductive material present in an effective amount to provide a field free region for ions when the conductive material is charged;

an outer tube surrounding the inner tube, the outer tube effective to insulate the inner tube and electrically isolate the inner tube;

an air gap between the inner tube and the outer tube; and

a reflectron assembly coupled to the inner tube, the reflectron assembly comprising a lens stack, in which each lens of the lens stack of the reflectron assembly comprises a first planar body comprising a first surface and a second surface, the first planar body comprising an aperture between a first side and a second side of the first surface of the first planar body, the first planar body further comprising a plurality of conductors spanning the aperture from the first side to the second side of the first surface of the first planar body, each of the plurality of conductors attached to the first surface of the first planar body at the first side and at the second side of the first surface, in which the plurality of conductors are each substantially parallel to each other and are positioned in the same plane, in which the first planar body further comprises a conductive element disposed on the first surface of the first planar body and in contact with each of the plurality of conductors to permit current flow from the planar conductive body to the plurality of conductors.

20. The time of flight tube assembly of claim 19 , further comprising a plurality of transverse rods coupled to each lens of the lens stack.