Barium iodide and strontium iodide crystals and scintillators implementing the same

• US 9,441,154 B2
• Filed: 03/20/2014
• Issued: 09/13/2016
• Est. Priority Date: 11/16/2007
• Status: Active Grant

• Current Assignee: Fisk University, Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Fisk University, Lawrence Livermore National Security LLC (Government of the United States of America)
• Inventors: Payne, Stephen A., Cherepy, Nerine, Pedrini, Christian, Burger, Arnold
• Primary Examiner(s): Hoban, Matthew E
• Assistant Examiner(s): EDMONDSON, LYNNE RENEE
• Application Number:
  US14/220,904
• Publication Number:
  US 20140361221A1
• Time in Patent Office: 908 Days
• Field of Search: 252/301.4 H, 252/301.4 R, 252/301.17, 250/370.11, 423/497
• US Class Current: 1/1
• CPC Class Codes: C09K 11/7733 with alkali or alkaline earth metals
• CPC Class Codes: C09K 11/7772 Halogenides C09K11/7767 takes precedence
• CPC Class Codes: C09K 11/7791 with alkali or alkaline earth metals
• CPC Class Codes: C30B 11/00 Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method C30B13/00, C30B15/00, C30B17/00, C30B19/00 take precedence; under a protective fluid C30B27/00
• CPC Class Codes: C30B 29/12 Halides
• CPC Class Codes: G01T 1/202 the detector being a crystal
• CPC Class Codes: G01T 1/2023 Selection of materials see provisionally also G01T1/202
• 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

Abstract

In one embodiment, a crystal includes at least one metal halide; and an activator dopant comprising ytterbium. In another general embodiment, a scintillator optic includes: at least one metal halide doped with a plurality of activators, the plurality of activators comprising: a first activator comprising europium, and a second activator comprising ytterbium. In yet another general embodiment, a method for manufacturing a crystal suitable for use in a scintillator includes mixing one or more salts with a source of at least one dopant activator comprising ytterbium; heating the mixture above a melting point of the salt(s); and cooling the heated mixture to a temperature below the melting point of the salts. Additional materials, systems, and methods are presented.

Claims

1. A single crystal, comprising:

at least one metal halide, wherein the at least one metal halide comprises beryllium iodide;

an activator dopant comprising ytterbium, wherein the ytterbium is divalent; and

at least one compound selected from a group consisting of;

a selenide, and a telluride.

2. The crystal of claim 1, wherein the at least one metal halide further comprises an alkaline earth halide comprising a metal selected from a group consisting of strontium, barium and calcium.

3. The crystal of claim 2, comprising:

at least one additional activator dopant, wherein the additional activator dopant comprises europium primarily in the form of Eu²⁺;

wherein the activator dopant is present in an amount ranging from about 0.5 mol % to about 10.0 mol % and the additional activator dopant is present in an amount less than an amount in which the activator dopant is present;

wherein the one or more metal halides comprise;

magnesium iodide;

calcium iodide;

strontium iodide;

barium iodide;

lithium iodide;

sodium iodide;

potassium iodide;

rubidium iodide; and

cesium iodide; and

wherein the crystal has a volume of at least one cubic centimeter; and

wherein the crystal has at least one face with an area of at least approximately one square centimeter.

4. The crystal of claim 1, wherein the crystal has a volume of at least one cubic centimeter.

5. The crystal of claim 1, wherein the crystal has at least one face with an area of at least approximately one square centimeter.

6. The crystal of claim 1, wherein the activator dopant is present in an amount ranging from about 0.5 mol % to about 10.0 mol %.

7. The crystal of claim 1, further comprising at least one additional metal halide, wherein the additional metal halide is selected from a group consisting of a strontium chloride, a barium chloride and a calcium chloride.

8. The crystal of claim 1, further comprising at least one additional activator dopant, wherein the additional activator dopant comprises europium primarily in the form of Eu²⁺.

9. The crystal of claim 8, wherein the additional activator dopant is present in an amount less than an amount in which the activator dopant is present.

10. A scintillator optic, comprising:

at least one metal halide doped with a plurality of activators, the plurality of activators comprising a first activator and a second activator; and

at least one compound selected from a group consisting of;

a selenide, and a telluride;

wherein the at least one metal halide comprises beryllium iodide and magnesium iodide;

wherein the first activator comprises divalent europium; and

wherein the second activator comprises divalent ytterbium.

17. The scintillator optic of claim 10,

wherein the second activator is present in an amount ranging from about 0.5 mol % to about 10.0 mol % and the first activator is present in an amount less than an amount in which the second activator is present;

wherein the at least one metal halide further comprises;

rubidium iodide; and

wherein the optic comprises at least one single crystal formed from the at least one metal halide;

wherein the at least one single crystal has a volume of at least one cubic centimeter; and

wherein the at least one single crystal has at least one face with an area of at least approximately one square centimeter.

11. A method for manufacturing a crystal suitable for use in a scintillator, the method comprising:

mixing one or more salts comprising beryllium iodide, magnesium iodide, and at least one of;

a selenide and a telluride with a source of at least one dopant activator comprising divalent ytterbium;

heating the mixture above a melting point of the salts; and

cooling the heated mixture to a temperature below the melting point of the salts.

12. The method of claim 11, wherein the one or more salts further comprise:

at least one metal cation; and

at least one anion selected from a group consisting of;

a borate, a carbonate, a nitrate, a phosphate, and a sulfide.

13. The method of claim 11, wherein the one or more salts further comprise at least one of:

calcium iodide;

strontium iodide;

barium iodide;

lithium iodide;

sodium iodide;

potassium iodide;

rubidium iodide; and

cesium iodide.

14. The method of claim 11, wherein the at least one dopant activator further comprises europium present in an amount less than the ytterbium, wherein each of the europium and the ytterbium are primarily divalent.

15. The method of claim 11, wherein the crystal is embodied as a single crystal having a volume of at least one cubic centimeter.

16. The method of claim 11, wherein the crystal is embodied as a single crystal having at least one face with an area of at least approximately one square centimeter.