Nanocomposite scintillator and detector

• US 20080128624A1
• Filed: 03/27/2007
• Published: 06/05/2008
• Est. Priority Date: 12/21/2005
• Status: Active Grant

• Current Assignee: TRIAD National Security, LLC
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Burrell, Anthony K., McCleskey, T. Mark, Bennett, Bryan L., Ott, Kevin C., Del Sesto, Rico E., Muenchausen, Ross E., McKigney, Edward A., Cooke, D. Wayne
• Granted Patent: US 7,547,888 B2
• Time in Patent Office: Days
• US Class Current: 250/361R
• CPC Class Codes: G01T 1/2023 Selection of materials see provisionally also G01T1/202

Abstract

A nanocomposite scintillator is prepared using fast, bright, rare-earth doped nanopowder phosphor and a binder that is transparent to the emission of the phosphor.

Claims

1. A compact comprising a mixture of a solid binder and at least one nanopowder phosphor chosen from yttrium oxide, yttrium tantalate, barium fluoride, cesium fluoride, bismuth germanate, zinc gallate, calcium magnesium pyrosilicate, calcium molybdate, calcium chlorovanadate, barium titanium pyrophosphate, a metal tungstate, a cerium doped nanophosphor, a bismuth doped nanophosphor, a lead doped nanophosphor, a thallium doped sodium iodide, a doped cesium iodide, a rare earth doped pyrosilicate, or a lanthanide halide.

2. The compact of claim 1, wherein said metal tungstate comprises lead tungstate, zinc tungstate, calcium tungstate, magnesium tungstate or cadmium tungstate.

3. The compact of claim 1, wherein said cerium doped nanophosphor is a cerium doped oxyorthosilicate, or of a formula LaX₃:

Ce wherein X is at least one halide chosen from fluoride, chloride, bromide, and iodide, a cerium doped lanthanum halosilicate of a formula LaSiO₃X;

Ce wherein X is at least one halide chosen from fluoride, chloride, bromide, and iodide, an alkaline earth fluoride of a formula MF₂;

Ce wherein M is at least one alkaline earth chosen from barium, calcium, strontium and magnesium, an alkaline earth sulfate of a formula MSO₄;

Ce wherein M is at least one alkaline earth chosen from barium, calcium, and strontium, an alkaline earth thiogallate of a formula MGa₂S₄;

Ce wherein M is at least one alkaline earth chosen from barium, calcium, strontium and magnesium, alkaline earth aluminates of a formula LMAI₁₀O₁₇;

Ce and CeLMAI₁₁O₁₈;

Ce wherein L, M are at least two alkaline earth chosen from barium, calcium, strontium and magnesium, alkaline earth pyrosilicates of a formula L₂MSi₂O₇;

Ce wherein L, M are at least two alkaline earth chosen from calcium, and magnesium, a cerium doped metal aluminum perovskite MAIO₃;

Ce wherein M is at least one metal chosen from yttrium and lutetium, a cerium doped alkaline earth sulphide of formula MS;

Ce wherein M is at least one alkaline earth chosen from strontium and magnesium, a cerium doped yttrium borate, a cerium doped yttrium aluminum borate, a cerium doped yttrium aluminum garnet, a cerium doped yttrium oxychloride, a cerium doped calcium silicate, a cerium doped calcium aluminum silicate, a cerium doped yttrium phosphate, a cerium doped calcium aluminate, a cerium doped calcium pyroaluminate, a cerium doped calcium phosphate, a cerium doped calcium pyrophosphate, or a cerium doped lanthanum phosphate.

4. The compact of claim 1, wherein said bismuth doped nanophosphor comprises a host lattice chosen from an alkaline earth phosphate of a formula LM₂(PO₄)₂:

Bi wherein M is at least one alkaline earth chosen from barium, calcium, and strontium, a lanthanide metal oxide of a formula M₂O₃;

Bi wherein M is at least one metal chosen from yttrium and lanthanum, a bismuth doped yttrium aluminum borate, a bismuth doped lanthanum oxychloride, a bismuth doped zinc oxide, a bismuth doped calcium oxide, a bismuth doped calcium titanium aluminate, a bismuth doped calcium sulphide, a bismuth doped strontium sulphate, or a bismuth doped gadolinium niobate.

5. The compact of claim 1, wherein said lead doped nanophosphor is chosen from alkaline earth sulfates of formula MSO₄:

Pb wherein M is at least one alkaline earth chosen from calcium and magnesium, alkaline earth borates of formula MB₄O₇;

Pb and MB₂O₄;

Pb wherein M is at least one alkaline earth chosen from calcium and strontium, an alkaline earth chloroborate of a formula M₂B₅O₉Cl;

Pb wherein M is at least one alkaline earth chosen from barium, calcium, and strontium, a lead doped barium oxyorthosilicate, a lead doped calcium oxide, a lead doped calcium sulfide, a lead doped zinc sulfide, a lead doped lanthanum oxide, a lead doped calcium silicate, a lead doped calcium tungstate, a lead doped barium oxyorthosilicate, a lead doped calcium chlorosilicate, a lead doped calcium phosphate, a lead doped calcium thiogallate

6. The compact of claim 1, wherein said doped cesium iodide comprises a dopant chosen from Na and Tl.

7. The compact of claim 1, wherein said rare earth doped pyrosilicate comprises a rare earth dopant chosen from Ce, Sm, Tb, Tm, Eu, Yb, and Pr.

8. The compact of claim 1, wherein said nanopowder phosphor comprises a host lattice chosen from lutetium oxyorthosilicate (LSO), gadolinium oxyorthosilicate (GSO), yttrium oxyorthosilicate (YSO), lutetium yttrium oxyorthosilicate (LYSO), gadolinium yttrium oxyorthosilicate (GYSO), lutetium gadolinium oxyorthosilicate (LGSO), and lanthanum halide.

9. The compact of claim 1, wherein the lanthanide halide is of a formula CeX₃ wherein X is at least one halide chosen from fluoride, chloride, bromide, and iodide.

10. The compact of claim 1, wherein said binder is transparent to light emitted by the rare earth doped nanopowder phosphor.

11. The compact of claim 1, wherein said binder comprises a polymer or a polymer with an index-matching additive.

12. The compact of claim 1, wherein said binder comprises a chalcogenide, flint, or lanthanum flint glass.

13. The compact of claim 1, wherein said nanopowder phosphor comprises a first refractive index and the solid binder comprises a second refractive index, and wherein the first refractive index and the second refractive index are equal.

14. The compact of claim 1, wherein said nanopowder phosphor comprises a first refractive index n_nano and the solid binder comprises a second refractive index n_matrix, and wherein −

0.02≦

n_nano−

n_matrix≦

0.02.

15. The compact of claim 1, wherein said compact comprises an amount of nanopowder phosphor in a range of greater than 1 percent by volume to about 70 percent by volume.

16. The compact of claim 1, wherein said nanopowder phosphor comprises a particle size P, wherein P≦

100 nanometers.

17. The compact of claim 1, wherein said nanopowder phosphor comprises a particle size P, wherein P≦

20 nanometers.

18. The compact of claim 1, wherein said nanopowder phosphor comprises a particle size P, wherein P≦

10 nanometers.

19. The compact of claim 1, wherein said nanopowder phosphor comprises a particle size P, wherein P≦

5 nanometers.

22. The radiation detector of claim 19, wherein said photodetector comprises a photodiode or photomultiplier.

20. A radiation detection method, comprising:

exposing a compact to ionizing radiation, wherein the compact comprises a mixture of a solid binder and at least one nanopowder phosphor chosen from yttrium oxide, yttrium tantalate, barium fluoride, cesium fluoride, bismuth germanate, zinc gallate, calcium magnesium pyrosilicate, calcium molybdate, calcium chlorovanadate, barium titanium pyrophosphate, a metal tungstate, a cerium doped nanophosphor, a bismuth doped nanophosphor, a lead doped nanophosphor, a thallium doped sodium iodide, a doped cesium iodide, a rare earth doped pyrosilicate, or a lanthanide halide; and

detecting luminescence from the compact.

21. A radiation detector, comprising:

a compact comprising a mixture of a solid binder and at least one nanopowder phosphor chosen from yttrium oxide, yttrium tantalate, barium fluoride, cesium fluoride, bismuth germanate, zinc gallate, calcium magnesium pyrosilicate, calcium molybdate, calcium chlorovanadate, barium titanium pyrophosphate, a metal tungstate, a cerium doped nanophosphor, a bismuth doped nanophosphor, a lead doped nanophosphor, a thallium doped sodium iodide, a doped cesium iodide, a rare earth doped pyrosilicate, or a lanthanide halide; and

a photodetector optically coupled to said compact.

23. A composition comprising nanophosphor particles of the formula Ce_nLa₍₁₋

n)X₃(oleic acid), wherein X is chosen from fluoride and bromide, and wherein 1≧

n≧

0.