Scintillator based microscope

• US 6,091,796 A
• Filed: 10/28/1996
• Issued: 07/18/2000
• Est. Priority Date: 11/23/1994
• Status: Expired due to Fees

• Current Assignee: Trex Enterprises Corporation
• Original Assignee: Thermotrex Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: Spivey, Brett, Horton, Steve, Trissel, Richard, Morsell, Lee
• Primary Examiner(s): Wong, Don
• Application Number:
  US08/736,716
• Time in Patent Office: 1,359 Days
• Field of Search: 378/43, 378/98.3, 378/98.8, 250/368, 250/361 R, 250/363.01
• US Class Current: 378/43
• CPC Class Codes: G21K 4/00 Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens photographic processes using X-ray intensifiers G03C5/17; discharge tubes comprising luminescent screens H01J1/62; cathode ray tubes for X-ray conversion with optical output H01J31/50
• CPC Class Codes: G21K 7/00 Gamma- or X-ray microscopes

Abstract

A scintillation based microscope. One surface of a single crystal salt crystal scintillator is supported on an optically transparent support plate. The opposite surface, an illumination surface, of the crystal is coated with an optically reflecting material which is transparent to high energy photons (such as x-ray and/or high energy ultraviolet photons) in order to provide a scintillation sandwich having an optical mirror at the illumination surface of the crystal. These high energy photons are directed through a target to create a shadow image of the target on the illumination surface of the scintillator salt crystal. A portion or all of the shadow image is viewed with an optical device such as an eye piece to provide a very high resolution image of the target or portions of the target. In a preferred embodiment an adjustable pin hole unit is described to produce a very small x-ray spot source for producing high resolution geometric magnification of the shadow image of the target.

Claims

1. A scintillator based microscope image system comprising:

a) a source of high energy photons;

b) a substantially rigid optically transparent support plate;

c) a single crystal scintillation crystal in the form of a crystalline plate defining a peak scintillation wavelength and mounted on said support plate, said scintillation crystal defining an illumination surface and a viewing surface, said illumination surface being covered with an optical reflector to define an optically reflecting illumination surface, and both viewing surface and said optically reflecting illumination surface being treated to reduce Fresnel reflections in said crystal at said peak scintillation wavelength to less than about 1.0 percent and to reduce surface roughness to less than about 100 angstroms;

wherein high energy photons from said source are directed through a target to illuminate said optically reflecting illumination surface to produce an image of said target at or near said optically reflecting illumination surface, directly from light created in said crystal and indirectly from light created in said crystal and reflected from said optical reflector; and

d) optical microscopic elements for producing a magnified view of said image at or near said optically reflecting illumination surface.

2. A microscope system as in claim 1 wherein said scintillation crystal is a single crystal CsI crystal.

3. A microscope system as in claim 1 wherein said CsI crystal is doped to produce a CsI (T1) crystal.

4. A microscope system as in claim 1 wherein said optical reflector is attached to said scintillation crystal with an optical grade adhesive.

5. A microscope system as in claim 4 wherein said scintillation crystal has a crystal index of refraction at said wavelength and said optical grade adhesive defines an adhesive index of refraction at said wavelength, said peak scintillation wavelength crystal index of refraction and said adhesive index of refraction being similar enough to reduce Fresnel reflections at said illumination surface to less than about 0.5%.

6. A microscope system as in claim 1 and further comprising an index matching fluid contained between said illumination surface and said optical reflector.

7. A microscope system as in claim 1 wherein said high energy photon source is an x-ray source.

8. A microscope system as in claim 1 wherein said high energy photon source is a high energy ultraviolet source.

9. A microscope system as in claim 1 wherein said high energy photon source is a gamma ray source.

10. A microscope system as in claim 7 and further comprising an adjustable pin hole unit to provide a simulated point high energy photon source.

11. A microscope system as in claim 10 wherein said adjustable pin hole unit comprises two sets of two spaced apart plates each set defining a narrow crack with varying widths.

12. A device for producing microscopic images comprising:

a) a substantially rigid optically transparent support plate;

b) a single crystal scintillation crystal in the form of a crystalline plate, defining a peak scintillation wavelength, mounted on said support plate, said scintillation crystal defining an illumination surface and a viewing surface said illumination surface being covered with an optical reflector transparent to high energy photons to define an optically reflecting illumination surface, and both viewing and said optically reflecting illumination surface being treated to reduce Fresnel reflections in said crystal at said peak scintillation wavelength to less than about 1.0 percent and to reduce surface roughness to less than about 100 angstroms;

c) an optical microscopic system for viewing said image at or near said optically reflecting illumination surface.

13. A device as in claim 12 wherein said scintillation crystal is a single crystal CsI crystal.

14. A device as in claim 12 wherein said CsI crystal is doped to produce a CsI (T1) crystal.

15. A device as in claim 12 wherein said optical reflector is attached to said scintillation crystal with an optical upgrade adhesive.

16. A device as in claim 15 wherein said scintillation crystal defines a crystal index of refraction at said peak sicntillation wavelength and said optical grade adhesive defines an index of refraction at said peak scintillation wavelength, said crystal index of refraction and said adhesive index of refraction being similar enough to reduce Fresnel reflections at said illumination to less than 0.5%.

17. A device as in claim 12 and further comprising an index matching fluid contained between said illumination surface and said optical reflector.

18. A device for producing a magnified x-ray image of a target comprising:

a) a substantially rigid optically transparent support plate;

b) a single crystal scintillation crystal in the form of a crystalline plate, defining a peak x-ray scintillation wavelength, mounted on said support plate, said scintillation crystal defining an x-ray illumination surface and a viewing surface, said illumination surface being covered with an x-ray transparent optical reflector to define an optically reflecting illumination surface, with index matching fluid covering said viewing surface and contained between said illumination surface and said optical reflector to reduce Fresnel reflections in said crystal at said peak x-ray scintillation wavelength to less than about 1.0 percent;

c) an x-ray source positioned to direct x-rays through said target to produce an image of at least a portion of said target at and near said illumination surface; and

d) a microscope for producing a magnified view of said image.

19. A method of making an image of at least a portion of a target utilizing a microscopic optical system and a scintillator comprising a single crystal scintillation crystal in the form of a plate, said scintillation crystal defining an illumination surface, said illumination surface being covered with an x-ray optical reflector transparent to high energy photons and defining an optically reflecting illumination surface, said optically reflecting illumination surface and said viewing surface being treated to reduce Fresnel reflection at each surface to less than about 0.5 percent, comprising the steps of:

a) illuminating said target with a beam of photons having sufficient energy such that a portion of said beam is absorbed in said target and a portion passes through said target to define a shadow x-ray beam;

a portion of said shadow x-ray beam passing through said reflector and being absorbed in said crystal to produce visible light scintillations in said crystal; and

b) focusing said microscopic optical system at or near said optically reflecting illumination surface to provide a magnified view of said image.

20. A method as in claim 19 and further comprising the steps of producing a simulated point photon source using an adjustable pin hole unit comprised of at least two photon absorbing units, each unit having a narrow crack of varying widths.

21. A method as in claim 20 wherein each of said absorbing units are positionable with a micrometer to provide a variable size simulated source.