Claims
- 1. An imaging camera, comprising:
a Fresnel lens having a center; a photocathode distanced from the Fresnel lens; a housing between the Fresnel lens and the photocathode; and an electron sensor disposed in the center of the Fresnel lens.
- 2. An imaging camera as recited in claim 1, wherein the housing includes an interior surface and the camera further comprises:
at least one conductive layer on the interior surface of the housing.
- 3. An imaging camera as recited in claim 2, wherein the imaging camera has a central axis and the imaging camera further comprises:
at least one optically passive surface established by the Fresnel lens parallel to the central axis; and at least one conductive layer on the optically passive surface.
- 4. An imaging camera as recited in claim 3, further comprising:
an electron lens established by the conductive layer on the interior of the housing and the conductive layer on the Fresnel lens.
- 5. An imaging camera as recited in claim 1, wherein the photocathode comprises a reflection mode photocathode.
- 6. An imaging camera as recited in claim 5, wherein the reflection mode photocathode comprises a 111-V NEA photocathode.
- 7. An imaging camera as recited in claim 5, wherein the reflection mode photocathode comprises a multi-alkali photocathode.
- 8. An imaging camera as recited in claim 1, wherein the electron sensor comprises a multi-pixel electron sensor.
- 9. An imaging camera as recited in claim 1, wherein the imaging camera is at least partially assembled at atmospheric pressure on earth.
- 10. An imaging camera as recited in claim 9, wherein assembly of the imaging camera is completed in space.
- 11. A Fresnel lens, comprising:
at least one optically passive surface parallel to a central axis of the Fresnel lens; and at least one conductive layer disposed on the optically passive surface.
- 12. A Fresnel lens as recited in claim 11, wherein said Fresnel lens is at least partially energizable by application of an electric potential to the conductive layer.
- 13. A Fresnel lens as recited in claim 11, further comprising:
a plurality of concentric optically passive surfaces parallel to the central axis; and a conductive layer disposed on each concentric optically passive surface.
- 14. A Fresnel lens as recited in claim 13, wherein said Fresnel lens is at least partially energizable by application of an electric potential to the conductive layer.
- 15. An imaging camera, comprising:
a housing having a proximal end and a distal end; a Fresnel lens installed in the proximal end of the housing; said Fresnel lens having a center; a photocathode installed in the distal end of the housing; an electron sensor disposed in the center of the Fresnel lens; and an electron lens at least partially established by the housing and the Fresnel lens.
- 16. An imaging camera as recited in claim 15, wherein the housing includes an interior surface and the camera further comprises:
at least one conductive layer on the interior surface of the housing.
- 17. An imaging camera as recited in claim 16, wherein the imaging camera has a central axis and the imaging camera further comprises:
at least one optically passive surface established by the Fresnel lens parallel to the central axis; and at least one conductive layer on the optically passive surface.
- 18. An imaging camera as recited in claim 17, wherein the electron lens is established by the conductive layer on the interior of the housing and the conductive layer on the Fresnel lens.
- 19. An imaging camera as recited in claim 15, wherein the photocathode comprises a reflection mode photocathode.
- 20. An imaging camera as recited in claim 19, wherein the reflection mode photocathode comprises a III-V NEA photocathode.
- 21. An imaging camera as recited in claim 19, wherein the reflection mode photocathode comprises a multi-alkali photocathode.
- 22. An imaging camera as recited in claim 15, wherein the electron sensor comprises a multi-pixel electron sensor.
- 23. An imaging camera as recited in claim 15, wherein the imaging camera is at least partially assembled at atmospheric pressure on earth.
- 24. An imaging camera as recited in claim 23, wherein assembly of the imaging camera is completed in space.
- 25. A method for making an imaging camera, comprising:
coating at least a portion of interior conductive surfaces of the imaging camera with getters; obtaining pieces of a photocathode that are protected by Arsenic; mounting the pieces of the photocathode on a substrate; filling the camera with a clean inert gas; activating the getters in the clean inert gas; launching the camera into space; establishing an ultrahigh vacuum; and removing the Arsenic layer.
- 26. A method as recited in claim 25, wherein the getters comprise evaporable getters.
- 27. A method as recited in claim 25, wherein the getters comprise non-evaporable getters film.
- 28. A method as recited in claim 25, wherein the pieces of the photocathode are grown epitaxially.
- 29. A method as recited in claim 25, wherein the clean inert gas comprises Argon.
- 30. A method as recited in claim 25, further comprising:
heating the photocathode layer to a temperature greater than 400 degrees Celsius.
- 31. A method as recited in claim 30, further comprising:
activating the clean surface of the photocathode.
- 32. A method as recited in claim 31, further comprising:
exposing the cleans surface of the photocathode to Cesium vapors and Oxygen vapors.
- 33. A method as recited in claim 32, further comprising:
alternatingly depositing layers of Cesium and Oxygen on the clean surface of the photocathode.
- 34. A method as recited in claim 33, further comprising:
re-activating the photocathode.
- 35. A method for making an imaging camera, comprising:
coating at least a portion of interior conductive surfaces of the imaging camera with getters; filling the camera with ultrapure inert gas; activating the getters within the in the ultrapure inert gas; providing a clean substrate; placing the substrate in an ultrahigh vacuum chamber; evaporating materials within the vacuum chamber to establish a multi-alkali photocathode on the substrate; filling the vacuum chamber with ultrapure inert gas; opening a load-lock door between the camera and the vacuum chamber; transporting the photocathode to the camera; and mounting the photocathode within the camera.
- 36. A method as recited in claim 35, further comprising:
maintaining the ultraclean inert gas around the photocathode.
- 37. A method as recited in claim 36, further comprising:
continuing purifying the ultraclean inert gas within the camera with the activated getters.
- 38. A method as recited in claim 37, further comprising:
launching the camera into space.
- 39. A method as recited in claim 38, further comprising:
evacuating the camera to remove the inert gas.
- 40. A method as recited in claim 35, wherein the getters comprise evaporable getters.
- 41. A method as recited in claim 35, wherein the getters comprise non-evaporable getters.
- 42. A method as recited in claim 35, wherein the ultrapure inert gas comprises Argon.
- 43. A method as recited in claim 35, wherein the clean substrate comprises a curved metallic substrate.
- 44. A method as recited in claim 35, wherein the ultrahigh vacuum chamber comprises a separate chamber connected to the camera via a load-lock door.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. provisional application serial No. 60/386,984 filed on Jun. 6, 2002, incorporated herein by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60386984 |
Jun 2002 |
US |