Photon counting ultraviolet spatial image sensor with microchannel photomultiplying plates

• US 5,461,226 A
• Filed: 10/29/1993
• Issued: 10/24/1995
• Est. Priority Date: 10/29/1993
• Status: Expired due to Term

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Loral Infrared And Imaging Systems, Inc. (Martin Marietta Corporation)
• Inventors: Clark, Warren L., Butler, Neal R., Nicoli, Anthony M., Hirs, John H.
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): NICHOLS, STEVEN
• Application Number:
  US08/145,392
• Time in Patent Office: 725 Days
• Field of Search: 250/214 VT, 250/207, 250/336.1, 250/365, 250/372, 313/527, 313/528, 313/539, 313/105 CM, 313/103 CM
• US Class Current: 250/214.0VT
• CPC Class Codes: G01J 1/429 applied to measurement of ultraviolet light using counting tubes G01T
• CPC Class Codes: G01S 3/782 Systems for determining direction or deviation from predetermined direction
• CPC Class Codes: G01T 1/2957 using channel multiplier arrays channel multipliers H01J43/18; G01T1/1645 takes precedence
• CPC Class Codes: H01J 2231/50021 Ultraviolet
• CPC Class Codes: H01J 2231/50068 Electrical
• CPC Class Codes: H01J 31/49 Pick-up adapted for an input of electromagnetic radiation other than visible light and having an electric output, e.g. for an input of X-rays, for an input of infrared radiation
• CPC Class Codes: H01J 31/507 using a large number of channels, e.g. microchannel plates

Abstract

An integrated optical system illuminates an ultraviolet spatial detector with an image from a field of interest. The ultraviolet spatial detector is comprised of an electron multiplying microchannel plate and a 100 pixel discrete anode array using a high strip current microchannel plate. The discrete anode array preserves the spatial distribution of the image. The ultraviolet spatial sensor has a wide field of view. The ultraviolet spatial detector has a photon counting sensor capable of detecting ultraviolet sources to determine their position to within plus or minus 4.5 degrees.

Claims

1. A spatial sensor apparatus comprising:

(a) an integrated filter-optic means for projecting a view of a scene in a predetermined frequency range having a scene output, where the integrated filter-optic means is comprised of a wide field of view lens integrated with an ultraviolet filter; and

(b) a photon counting spatial detector means for detecting photons of the predetermined frequency range and conserving their spatial position, wherein the photon counting spatial detector means is coupled to the scene output and has an image output.

2. The spatial sensor apparatus of claim 1 further comprising a counting means for counting photons coupled to the image output having a count output proportional to a number of incident photons at predetermined positions.

3. The spatial sensor apparatus of claim 1 wherein the photon counting spatial detector means comprises an anode array having at least 100 pixel anodes and a microchannel electron multiplying plate coupled to the anode array.

4. The spatial sensor apparatus of claim 2 wherein the count output is interfaced to a computer processor.

5. The spatial sensor apparatus of claim 2 wherein the count output is provided to a computer processor through a serial interface.

6. The spatial sensor apparatus of claim 2 wherein the count output is provided at a rate of at least a four kilohertz frame rate.

7. The spatial sensor apparatus of claim 1 wherein the photon counting spatial detector means provides a continuous staring operation with no more than 250 nanoseconds of dead time between frames.

8. The spatial sensor apparatus of claim 1 wherein the integrated filter-optic means detects images in the middle ultraviolet range while rejecting radiation outside the middle ultraviolet range.

9. A radiation sensing spatial sensor apparatus comprising:

(a) an integrated filter-optic means for projecting a view of a scene in a predetermined frequency range having a scene output, where the integrated filter-optic means is comprised of a wide field of view lens integrated with an ultraviolet filter;

(b) an imaging means for capturing radiation having an electron output, the imaging means being positioned to receive radiation transmitted through the integrated filter-optic means;

(c) a spatial distribution preserving electron multiplying means having an electron input coupled to the electron output and wherein the spatial distribution preserving electron multiplying means also has a gain electron output; and

(d) a means for spatially sensing an electron distribution having a spatial distribution input coupled to the gain electron output.

10. The radiation sensing spatial sensor apparatus of claim 9 wherein the imaging means further comprises a lens and a photocathode.

11. The radiation sensing spatial sensor apparatus of claim 9 wherein the spatial distribution preserving electron multiplying means comprises a microchannel plate Z stack.

12. The radiation sensing spatial sensor apparatus of claim 9 wherein the means for spatially sensing comprises a discrete anode array.

13. The radiation sensing spatial sensor apparatus of claim 9 wherein the means for spatially sensing comprises a discrete anode array comprising a plurality of anodes which are regularly spaced in a grid pattern.

14. The radiation sensing spatial sensor apparatus of claim 12 wherein the discrete anode array is arranged in a pattern to match the imaging means.

15. The radiation sensing spatial sensor apparatus of claim 10 where the photocathode is comprised of RbCsTe.

16. The radiation sensing spatial sensor apparatus of claim 9 wherein the radiation is in the ultraviolet range.