MULTI-COMPONENT RARE-EARTH GARNET SCINTILLATORS
20250313751 ยท 2025-10-09
Assignee
Inventors
- Mariya Zhuravleva (Knoxville, TN, US)
- Kaden Legrand Anderson (Knoxville, TN, US)
- Matheus Pianassola (Knoxville, TN, US)
- Charles L. Melcher (Oak Ridge, TN, US)
Cpc classification
G21K4/00
PHYSICS
C30B29/28
CHEMISTRY; METALLURGY
International classification
C30B29/28
CHEMISTRY; METALLURGY
Abstract
Multi-component rare-earth garnet optical materials comprising at least three different rare-earth elements and an optional activator ion are described. The optical materials include rare-earth garnet scintillators. Methods of preparing powders, ceramics, and single crystals of the optical materials are also described. In addition, radiation detectors comprising the rare-earth garnet scintillators are described.
Claims
1. An optical material comprising a composition of the formula: ##STR00004## wherein: 0y0.1; 0z1; RE is a combination of ions of three or more rare-earth elements selected from the group consisting of Y, Sc, Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Nd, Pr, and La; and X is one or more activator ions selected from the group consisting of a Ce ion, a Tb ion, a Dy ion, a Eu ion, an Yb ion, and a Pr ion.
2. The optical material of claim 1, wherein z is 0.
3. The optical material of claim 1, wherein RE is a combination of ions of three, four, five or six elements selected from the group consisting of Y, Sc, Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Nd, Pr, and La.
4. The optical material of claim 1, wherein RE is a combination of ions of at least three elements selected from the group consisting of Y, Lu, Tb, and Gd.
5. The optical material of claim 1, wherein y is 0.
6. The optical material of claim 1, wherein 0.001y0.1.
7. The optical material of claim 6, wherein 0.005y0.05; optionally wherein y is 0.005, 0.02, or 0.05.
8. The optical material of claim 6 wherein X is a Ce ion, a Pr ion, or a mixture thereof, optionally wherein X is Ce.sup.3+.
9. The optical material of claim 1, wherein the optical material comprises a composition selected from the group consisting of: (Y.sub.0.2Gd.sub.0.2Tb.sub.0.2Y.sub.0.2Lu.sub.0.2).sub.3Al.sub.5O.sub.12; (Y.sub.0.25Gd.sub.0.25Er.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12; (Y.sub.0.25Gd.sub.0.25Ho.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12; (Y.sub.0.2Gd.sub.0.2Tb.sub.0.2Dy.sub.0.2Lu.sub.0.2).sub.3Al.sub.5O.sub.12; (Y.sub.0.25Gd.sub.0.25Tb.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12; (Y.sub.0.2Eu.sub.0.2Gd.sub.0.2Yb.sub.0.2Lu.sub.0.2).sub.3Al.sub.5O.sub.12; (Y.sub.0.1667Eu.sub.0.1667Gd.sub.0.1667Tb.sub.0.1667Yb.sub.0.1667Lu.sub.0.1667).sub.3Al.sub.5O.sub.12; (Y.sub.0.25Gd.sub.0.25Tb.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12; (Y.sub.0.25Nd.sub.0.25Gd.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12; (Y.sub.0.25Pr.sub.0.25Gd.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12; and (Y.sub.0.25La.sub.0.25Gd.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12.
10. The optical material of claim 1, wherein the optical material comprises a composition selected from the group consisting of: (Y.sub.0.199Gd.sub.0.199Tb.sub.0.199Yb.sub.0.199Lu.sub.0.199Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Y.sub.0.24875Gd.sub.0.24875Er.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Y.sub.0.24875Gd.sub.0.24875Ho.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Y.sub.0.199Gd.sub.0.199Tb.sub.0.199Dy.sub.0.199Lu.sub.0.199Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Y.sub.0.24875Gd.sub.0.24875Tb.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Y.sub.0.199Eu.sub.0.199Gd.sub.0.199Yb.sub.0.199Lu.sub.0.199Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Y.sub.0.16583Eu.sub.0.16583Gd.sub.0.16583Tb.sub.0.16583Yb.sub.0.16583Lu.sub.0.16583Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Y.sub.0.24875Sm.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Y.sub.0.24875Nd.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Y.sub.0.24875Pr.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sup.12; (Y.sub.0.24875La.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sup.12; (Y.sub.0.245Gd.sub.0.245Tb.sub.0.245Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sup.12; (Y.sub.0.2375Gd.sub.0.2375Tb.sub.0.2375Lu.sub.0.2375Ce.sub.0.005).sub.3Al.sub.5O.sup.12; (Y.sub.0.2375Gd.sub.0.2375Tb.sub.0.2375Lu.sub.0.2375Ce.sub.0.005).sub.3Al.sub.5O.sup.12; and (Y.sub.0.294Gd.sub.0.294Tb.sub.0.098Lu.sub.0.294Ce.sub.0.02).sub.3Al.sub.5O.sub.12.
11. The optical material of claim 1, wherein the optical material comprises a composition selected from the group consisting of: (Y.sub.0.33167Tb.sub.0.33167Gd.sub.0.33167Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Lu.sub.0.33167Yo.sub.0.33167Gd.sub.0.33167Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Lu.sub.0.33167Yo.sub.0.33167Tb.sub.0.33167Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Lu.sub.0.24875Yo.sub.0.24875Tb.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; and (Lu.sub.0.245Yo.sub.0.245Tb.sub.0.245Ce.sub.0.002).sub.3Al.sub.5O.sub.12; and
12. An optical material of claim 1, wherein the optical material provides light emission from an optically active RE ion upon stimulation of the optical material with high energy radiation, optionally wherein said optically active RE ion is a Tb ion.
13. A radiation detector comprising an optical material of claim 1 and a photon detector, optionally wherein the optical material is an optical material selected from the group consisting of: (Y.sub.0.33167Tb.sub.0.33167Gd.sub.0.33167Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Lu.sub.0.33167Yo.sub.0.33167Gd.sub.0.33167Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Lu.sub.0.33167Yo.sub.0.33167Tb.sub.0.33167Ce.sub.0.005).sub.3Al.sub.5O.sub.12; (Lu.sub.0.24875Yo.sub.0.24875Tb.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; and (Lu.sub.0.245Y.sub.0.245Tb.sub.0.245Gd.sub.0.245Ce.sub.0.02).sub.3Al.sub.5O.sub.12.
14. A method of detecting gamma rays, X-rays, cosmic rays, and/or particles having an energy of 1 keV or greater, the method comprising using the radiation detector of claim 13.
15. Use of a radiation detector of claim 13 in medical imaging, homeland security, or high energy physics research.
16. A method of preparing an optical material of claim 1, wherein the method comprises preparing a single crystal of the optical material from a melt.
17. A method of preparing an optical material of claim 1, wherein the method comprises preparing a powder of the optical material by: (i) preparing a foam by heating an aqueous solution comprising a polymer, optionally polyvinyl alcohol (PVA) or polyethylene glycol (PEG), and a mixture of metal nitrates, wherein the metal nitrates comprise ions of elements that correspond to elements of the optical material, and crushing said foam to provide the powder; or (ii) coprecipitating powder by adding an aqueous solution comprising a mixture of metal nitrates and ammonium sulfate to an aqueous solution of ammonium carbonate, wherein the metal nitrates comprise ions of elements that correspond to elements of the optical material.
18. A method of preparing an optical material of claim 1, wherein the method comprises preparing a ceramic of the optical material by a technique selected from the group consisting of sintering, hot pressing, hot isotactic pressing, and spark plasma synthesis, optionally using binary oxides as starting materials.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
[0151] The presently disclosed subject matter will now be described more fully. The presently disclosed subject matter can, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein below and in the accompanying Examples. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the embodiments to those skilled in the art.
[0152] All references listed herein, including but not limited to all patents, patent applications and publications thereof, and scientific journal articles, are incorporated herein by reference in their entireties to the extent that they supplement, explain, provide a background for, or teach methodology, techniques, and/or compositions employed herein.
I. Definitions
[0153] While the following terms are believed to be well understood by one of ordinary skill in the art, the following definitions are set forth to facilitate explanation of the presently disclosed subject matter.
[0154] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter belongs.
[0155] Following long-standing patent law convention, the terms a, an, and the refer to one or more when used in this application, including the claims.
[0156] The term and/or when used in describing two or more items or conditions, refers to situations where all named items or conditions are present or applicable, or to situations wherein only one (or less than all) of the items or conditions is present or applicable.
[0157] The use of the term or in the claims is used to mean and/or unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and and/or. As used herein another can mean at least a second or more.
[0158] The term comprising, which is synonymous with including, containing, or characterized by is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. Comprising is a term of art used in claim language which means that the named elements are essential, but other elements can be added and still form a construct within the scope of the claim.
[0159] As used herein, the phrase consisting of excludes any element, step, or ingredient not specified in the claim. When the phrase consists of appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause, other elements are not excluded from the claim as a whole.
[0160] As used herein, the phrase consisting essentially of limits the scope of a claim to the specified materials or steps, plus those that do not materially affect the basic and novel characteristic(s) of the claimed subject matter.
[0161] With respect to the terms comprising, consisting of, and consisting essentially of, where one of these three terms is used herein, the presently disclosed and claimed subject matter can include the use of either of the other two terms.
[0162] Unless otherwise indicated, all numbers expressing quantities of time, temperature, light output, atomic (at) or mole (mol) percentage (%), and so forth used in the specification and claims are to be understood as being modified in all instances by the term about. Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.
[0163] As used herein, the term about, when referring to a value is meant to encompass variations of in one example 20% or 10%, in another example 5%, in another example 1%, and in still another example 0.1% from the specified amount, as such variations are appropriate to perform the disclosed methods.
[0164] The term scintillator refers to a material that emits light (e.g., visible light) in response to stimulation by high energy radiation (e.g., X, , , or radiation).
[0165] The term phosphor as used herein refers to a material that emits light (e.g., visible light) in response to irradiation with electromagnetic or particle radiation. Thus, phosphors are materials that can emit light (e.g., of a particular wavelength or wavelength range) upon exposure to ultraviolet or visible light (e.g., of a particular wavelength or wavelength range).
[0166] In some embodiments, the compositional formula expression of an optical material (e.g., a scintillation material or a phosphor) can contain a colon or comma, wherein the composition of the main or base matrix material (e.g., the main rare earth garnet matrix, i.e., RE.sub.3Al.sub.5O.sub.12) is indicated on the left side of the colon or comma, and an activator (or dopant ion) is indicated on the right side of the colon or comma. Alternatively, compositional formula expression can be free of a colon and the activator (or dopant), if present, can be included with the elements that it replaces, e.g., (RE/activator).sub.3Al.sub.5O.sub.12.
[0167] The term high energy radiation can refer to electromagnetic radiation having energy higher than that of ultraviolet radiation, including, but not limited to X radiation (i.e., X-ray radiation), alpha (a) particles, gamma () radiation, and beta (p) radiation. In some embodiments, the high energy radiation refers to gamma rays, cosmic rays, X-rays, and/or particles having an energy of 1 keV or greater. Scintillator materials as described herein can be used as components of radiation detectors in apparatuses such as counters, image intensifiers, and computed tomography (CT) scanners.
[0168] Optical coupling as used herein refers to a physical coupling between a scintillator and a photosensor, e.g., via the presence of optical grease or another optical coupling compound (or index matching compound) that bridges the gap between the scintillator and the photosensor. In addition to optical grease, optical coupling compounds can include, for example, liquids, oils and gels.
[0169] Light output can refer to the number of light photons produced per unit energy deposited, e.g., by a gamma ray being absorbed, typically the number of light photons/MeV.
[0170] As used herein, chemical ions can be represented simply by their chemical element symbols alone (e.g., Eu for europium ion(s) (e.g., Eu.sup.2+) or Sm for samarium ion(s) (e.g., Sm.sup.2+)).
[0171] The term rare earth element as used herein refers to one or more elements selected from a lanthanide (e.g., lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho) erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu)), scandium (Sc), and yttrium (Y).
[0172] The term transition metal element as used herein refers to one or more elements selected from titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), rutherfordium (Rf), dubnium (Db), seborgium (Sg), bohrium (Bh), hassium (Hs), meitnerium (Mt), darmstadtium (Ds), roentgenium (Rg), and copernicium (Cn).
II. Multi-Component Rare-Earth Garnet Materials and Related Devices and Methods
[0173] The presently disclosed subject matter provides multi-component rare-earth garnet optical materials. These optical materials can be phosphors and/or scintillators. In some embodiments, the optical materials comprise or consist of compositions of the general formula (RE.sub.1-yX.sub.y).sub.3(Al.sub.1-zGa.sub.z).sub.5O.sub.12, where RE represents ions of a combination of three or more rare-earth elements (including Y and Sc). The rare earth elements can thus be selected from the group including Y, Sc, Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Nd, Pr, and La. X represents a luminescent activator, e.g., a Ce ion, a Tb ion, a Dy ion, a Eu ion, a Yb ion, or a Pr ion, while y is the relative activator concentration, and is in the range of 0y0.1. Thus, between 0% and 10% of the total amount of rare-earth element ions (RE) can be replaced by one or more activator ions. Although small amounts of X ions (e.g., Ce, Tb, Dy, Eu, Yb, or Pr ions) can act as a luminescent activator, optically active matrix elements, e.g., Yb, Er, Ho, Dy, Tb, Gd, Eu, Sm, Nd, and Pr, which are typically present in larger amounts than the activator, can also contribute to luminescence. The relative concentration of Ga compared to Al in the garnet matrix, represented by variable z, is in the range 0z1. In addition, in some embodiments, some of the Al or Ga content can be replaced by a rare-earth element ion, e.g., a Sc ion.
[0174] The concentrations of rare-earth elements in the optical material main matrix (i.e., i.e., (RE).sub.3(Al.sub.1-zGa.sub.z).sub.5O.sub.12, an optical material without an activator or codopant ion) can be either equimolar or non-equimolar in the melt or alternatively in the finished crystal or ceramic. In the case of a stoichiometric congruently melting compound, in some embodiments, the concentrations of rare-earth elements are equimolar. For example, in a material with ions of four different rare-earth elements, each ion can comprise one fourth (i.e., 25%) of the total amount of RE ions. An exemplary formula with equimolar RE is, for instance, (Lu.sub.1/4Y.sub.1/4Tb.sub.1/4Gd.sub.1/4).sub.3Al.sub.5O.sub.12 (which can also be represented as (Lu.sub.0.25Y.sub.0.25Tb.sub.0.25Gd.sub.0.25).sub.3Al.sub.5O.sub.12, i.e., when the relative amount of particular RE ions in the formula is represented as a percentage rather than as a ratio).
[0175] In the case of an incongruently melting compound, in some embodiments, the concentrations of rare-earth elements can vary from equimolar as needed to obtain congruency. An exemplary formula where the rare-earth elements are not equimolar is, for example (Y.sub.3/8Dy.sub.1/8Tb.sub.1/4Gd.sub.1/4).sub.3Al.sub.5O.sub.12 (which can also be represented as (Y.sub.0.375Dy.sub.0.125Tb.sub.0.25Gd.sub.0.25).sub.3Al.sub.5O.sub.12). In some embodiments, the amount of activator ion X (relative to the total amount of RE ions), if present, such as Ce or Pr, is provided as a percentage (i.e., an atomic percentage) after the colon in an optical material formula (i.e., (RE).sub.3(Al.sub.1-zGa.sub.z).sub.5O.sub.12:X y %), as an alternative representation format to the general formula described above, i.e., (RE.sub.1-yX.sub.y).sub.3(Al.sub.1-zGa.sub.z).sub.5O.sub.12, where the relative amount of activator ion, X, is included as a ratio or percentage inside the parentheses also describing the combination of rare-earth element ions RE.
[0176] In the case of a wide variation in rare-earth element ionic radius, concentrations of rare-earth elements of different ionic radii can be adjusted to stabilize the cubic garnet phase or achieve congruent melting, taking into account the segregation at the solid-liquid interface. Examples of these include, but are not limited to, (Lu.sub.1/4Y.sub.1/4Tb.sub.1/4Gd.sub.1/4).sub.3(Al.sub.1/2Ga.sub.1/2).sub.5O.sub.12:Ce, (Y.sub.3/8Dy.sub.1/8Tb.sub.1/4Gd.sub.1/4).sub.3Al.sub.5O.sub.12:Ce, and (Lu.sub.1/9Y.sub.1/9Tb.sub.2/9Gd.sub.2/9Sm.sub.3/9).sub.3Al.sub.5O.sub.12:Ce.
[0177] In some embodiments, e.g., when doped with an activator such as trivalent Ce or Pr, the presently disclosed optical materials become scintillators suitable for radiation detection applications including medical imaging, homeland security, and high energy physics experiments.
[0178] Accordingly, in some embodiments, the presently disclosed subject matter provides an optical material comprising or consisting of a composition of the formula:
##STR00002##
wherein: 0y0.1; 0z1; RE is a combination of ions of three or more rare-earth elements selected from the group comprising Y, Sc, Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Nd, Pr, and La; and X is one or more activator ions selected from the group comprising a Ce ion, a Tb ion, a Dy ion, a Eu ion, a Yb ion, and a Pr ion. As noted above, the relative concentrations of each of the rare-earth element ions in the optical material can be about the same (i.e., equimolar) or can be different.
[0179] In some embodiments, z is 0. Thus, in some embodiments, the optical material does not include any Ga and the optical material comprises or consists of the formula (RE.sub.1-yX.sub.y).sub.3Al.sub.5O.sub.12.
[0180] In some embodiments, RE is a combination of ions of three, four, five or six elements selected from the group comprising Y, Sc, Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Nd, Pr, and La. In some embodiments, RE is a combination of ions of at least three elements selected from Y, Lu, Tb, and Gd. In some embodiments, RE comprises a Y ion. In some embodiments, RE comprises a Lu ion.
[0181] In some embodiments, y is 0 (and the optical material does not include an activator ion X). For example, in some embodiments, the optical material comprises or consists of a composition selected from the group comprising: [0182] (Y.sub.0.2Gd.sub.0.2Tb.sub.0.2Y.sub.0.2Lu.sub.0.2).sub.3Al.sub.5O.sub.12; (Y.sub.0.25Gd.sub.0.25Er.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12; [0183] (Y.sub.0.25Gd.sub.0.25Ho.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12; (Y.sub.0.2Gd.sub.0.2Tb.sub.0.2Dy.sub.0.2Lu.sub.0.2).sub.3Al.sub.5O.sub.12; [0184] (Y.sub.0.25Gd.sub.0.25Tb.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12; (Y.sub.0.2Eu.sub.0.2Gd.sub.0.2Yb.sub.0.2Lu.sub.0.2).sub.3Al.sub.5O.sub.12; [0185] (Y.sub.0.1667Eu.sub.0.1667Gd.sub.0.1667Tb.sub.0.1667Yb.sub.0.1667Lu.sub.0.1667).sub.3Al.sub.5O.sub.12; (Y0.25Gdo.25 Tb0.25Luo.25) 3Al5012; (Y0.25Ndo.25Gdo.25Lu0.25)3AlsO12; (Y0.25Pro.25Gdo.25LU0.25)3AlsO12; and (Y0.25La0.25Gdo.25LU0.25)3Al5012.
[0186] In some embodiments, the optical material includes at least some amount of one or more activator ion. In some embodiments, 0.001y0.1 (i.e., the optical material includes 0.1% activator (i.e., 0.1 at % activator ion relative to the total amount of RE ions) to 10% activator. In some embodiments, 0.005y0.05 (e.g., 0.005, 0.006, 0.007, 0.008, 0.009, 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, or 0.050). In some embodiments, y is 0.005, 0.02 or 0.05. In some embodiments, X is a Ce ion, a Pr ion, or a Tb ion. In some embodiments, X is a Ce ion, a Pr ion, or a mixture thereof. In some embodiments, X is Ce.sup.3+.
[0187] In some embodiments, the optical material comprises or consists of a composition selected from the group comprising: [0188] (Y.sub.0.199Gd.sub.0.199Tb.sub.0.199Yb.sub.0.199Lu.sub.0.199Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0189] (Y.sub.0.24875Gd.sub.0.24875Er.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0190] (Y.sub.0.24875Gd.sub.0.24875Ho.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0191] (Y.sub.0.199Gd.sub.0.199Tb.sub.0.199Dy.sub.0.199Lu.sub.0.199Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0192] (Y.sub.0.24875Gd.sub.0.24875Tb.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0193] (Y.sub.0.199Eu.sub.0.199Gd.sub.0.199Yb.sub.0.199Lu.sub.0.199Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0194] (Y.sub.0.16583Eu.sub.0.16583Gd.sub.0.16583Tb.sub.0.16583Yb.sub.0.16583Lu.sub.0.16583Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0195] (Y.sub.0.24875Sm.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0196] (Y.sub.0.24875Nd.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0197] (Y.sub.0.24875Pr.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0198] (Y.sub.0.24875La.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0199] (Y.sub.0.245Gd.sub.0.245Tb.sub.0.245Lu.sub.0.245Ce.sub.0.002).sub.3Al.sub.5O.sub.12; [0200] (Y.sub.0.2375Gd.sub.0.2375Tb.sub.0.2375Lu.sub.0.2375Ce.sub.0.05).sub.3Al.sub.5O.sub.12; [0201] (Y.sub.0.2375Gd.sub.0.2375Tb.sub.0.2375Lu.sub.0.2375Ce.sub.0.05).sub.3Al.sub.5O.sub.12; and [0202] (Y.sub.0.294Gd.sub.0.294Tb.sub.0.098Lu.sub.0.294Ce.sub.0.02).sub.3Al.sub.5O.sub.12.
[0203] In some embodiments, the optical material comprises or consists of a composition selected from the group comprising: [0204] (Y.sub.0.33167Tb.sub.0.33167Gd.sub.0.33167Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0205] (Lu.sub.0.33167Y.sub.0.33167Gd.sub.0.33167Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0206] (Lu.sub.0.33167Y.sub.0.33167Tb.sub.0.33167Ce.sub.0.005).sub.3Al.sub.5O.sub.12; [0207] (Lu.sub.0.24875Y.sub.0.24875Tb.sub.0.24875Gd.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12; and [0208] (Lu.sub.0.245Y.sub.0.245Tb.sub.0.245Gd.sub.0.245Ce.sub.0.002).sub.3Al.sub.5O.sub.12; and
[0209] In some embodiments, the optical material provides light emission from an optically active RE ion upon stimulation of the optical material with high energy radiation. In some embodiments, the optically active RE ion is a Dy ion, Er ion, Sm ion, Eu ion, Yb ion, Tb ion, or Pr ion, or any combination of any of the foregoing. In some embodiments, the optically active RE ion is a Tb ion or a Pr ion. In some embodiments, the optically active RE ion is a Tb ion. In some embodiments, the optical material includes an optically active RE ion, such as a Tb ion, as one of the RE ions and further includes another ion as an activator ion, such as, a Ce ion, a Dy ion, a Eu ion, a Yb ion, or a Pr ion. Alternatively, in some embodiments, Tb is used as an activator ion (e.g., at a relative at % compared to other RE ions of 10 atomic % or less) and the optical material includes ions of at least three other RE elements.
[0210] The optical material can be provided as a single crystal, a polycrystalline material, a powder (e.g., a green powder), or a ceramic.
III. Radiation Detectors, Related Devices and Methods
[0211] In some embodiments, the presently disclosed subject matter provides a radiation detector comprising an optical material as described hereinabove or a mixture of such materials. For instance, the radiation detector can comprise an optical material that has the ability to act as a scintillator (which absorbs radiation and emits light) and a photodetector (which detects said emitted light). The photodetector can be any suitable detector or detectors and can be or not be optically coupled to the optical material for producing an electrical signal in response to emission of light from the optical material. Thus, the photodetector can be configured to convert photons to an electrical signal. For example, a signal amplifier can be provided to convert an output signal from a photodiode into a voltage signal. The signal amplifier can also be designed to amplify the voltage signal. Electronics associated with the photodetector can be used to shape and digitize the electronic signal.
[0212] Referring now to
[0213] Referring again to
[0214] In some embodiments, the radiation detector is configured for use as part of a medical or veterinary diagnostic device, a device for oil or other geological exploration (e.g., oil well logging probes), or as a device for security and/or military-related purposes (e.g., as a device for container, vehicle, or baggage scanning or for scanning humans or other animals). In some embodiments, the medical or veterinary diagnostic device is selected from, but not limited to, a positron emission tomography (PET) device, an X-ray computed tomography (CT) device, a radiography device, a single photon emission computed tomography (SPECT) device, or a planar nuclear medical imaging device. For example, the radiation detector can be configured to move (e.g., via mechanical and/or electronic controls) over and/or around a sample, such as a human or animal subject, such that it can detect radiation emitted from any desired site or sites on the sample. In some embodiments, the detector can be set or mounted on a rotating body to rotate the detector around a sample. In some embodiments, the radiation detector is configured for use in CT, radiography, or high energy physics research.
[0215] In some embodiments, the device can also include a radiation source. For instance, an X-ray CT device of the presently disclosed subject matter can include an X-ray source for radiating X-rays and a detector for detecting said X-rays. In some embodiments, the device can comprise a plurality of radiation detectors. The plurality of radiation detectors can be arranged, for example, in a cylindrical or other desired shape, for detecting radiation emitted from various positions on the surface of a sample.
[0216] In some embodiments, the presently disclosed subject matter provides a method for detecting radiation (or the absence of radiation) using a radiation detector comprising a rare-earth garnet optical material (i.e., a scintillator material comprising a rare-earth garnet optical material) as described hereinabove. Thus, in some embodiments, the presently disclosed subject matter provides a method of detecting gamma rays, X-rays, cosmic rays and particles having an energy of 1 keV or greater, wherein the method comprises using a radiation detector comprising a rare-earth garnet optical material as disclosed herein or a mixture of such materials. In some embodiments, the method comprises using the radiation detector in computed tomography, radiography, or high energy physics research.
[0217] In some embodiments, the method can comprise providing a radiation detector comprising a photodetector and rare-earth garnet optical material of the presently disclosed subject matter; positioning the detector, wherein the positioning comprises placing the detector in a location wherein the optical material is in the path of a beam of radiation (or the suspected path of a beam of radiation); and detecting light (or detecting the absence of light) emitted by the optical material with the photodetector. Detecting the light emitted by the optical material can comprise converting photons to an electrical signal. Detecting can also comprise processing the electrical signal to shape, digitize, or amplify the signal. The method can further comprise displaying the electrical signal or processed electrical signal.
[0218] In some embodiments, the presently disclosed subject matter provides for the use of a radiation detector comprising a photon detector and a scintillator material comprising a rare-earth garnet optical material as described hereinabove. In some embodiments, the use is for medical or veterinary diagnostics (e.g., the radiation detector is configured for use in medical or veterinary diagnostics). In some embodiments, the use is in computed tomography, radiography, or high energy physics research.
IV. Methods of Preparation of Optical Materials
[0219] The presently disclosed materials can be prepared by any suitable route, such as but not limited to a crystal synthesis route, a powder synthesis route, or a ceramic synthesis route. Representative, non-limiting examples of such routes are disclosed in the Examples below, and other examples of such routes and other synthesis routes as would be apparent to one of ordinary skill in the art upon a review of the instant disclosure also fall within the scope of the presently disclosed subject matter.
[0220] For example, in some embodiments, the appropriate reactants (e.g., metal nitrates or metal oxides, such as Lu.sub.2O.sub.3, CeO.sub.2, Pr.sub.6O.sub.3, -Al.sub.2O.sub.3, Ga.sub.2O.sub.3, Gd.sub.2O.sub.3, etc.) are melted at a temperature sufficient to form a congruent, molten composition. The melting temperature can depend on the identity of the reactants themselves (e.g., on the melting points of the individual reactants), but is usually in the range of from about 300 C. to about 1350 C. Exemplary techniques for preparing the materials include, but are not limited to, the Bridgman or Bridgman-Stockbarger method, the Czochralski method, the zone-melting method (or floating zone method), the vertical gradient freeze (VGF) method, and temperature gradient methods.
[0221] For instance, in some embodiments, high purity reactants can be mixed and melted to synthesize a compound of the desired composition. A single crystal or polycrystalline material can be grown from the synthesized compound by the Bridgman method, in which a sealed ampoule containing the synthesized compound is transported from a hot zone to a cold zone through a controlled temperature gradient at a controlled speed (i.e., a pulling rate). In some embodiments, high purity reactants can be mixed in stoichiometric ratios depending upon the desired composition of the optical material and loaded into an ampoule, which is then sealed. After sealing, the ampoule is heated and then cooled at a controlled speed. In some embodiments, an optical material (e.g., a scintillator material) of the presently disclosed subject matter is prepared via the vertical Bridgman technique. In some embodiments, the pulling (or translation) rate used in preparing scintillator crystals via the Bridgman technique is about 0.1 millimeters per hour (mm/hr) to about 5 mm/hr (e.g., about 0.1 mm/hr; about 0.5 mm/hr, about 1 mm/hr, about 2 mm/hr, about 3 mm/hr, about 4 mm/hr, or about 5 mm/hr). In some embodiments, the method comprises using a pulling rate of about 3 mm/h.
[0222] In some embodiments, the presently disclosed subject matter provides a method of preparing an optical material comprising a rare-earth garnet (RE).sub.3(AlGa).sub.5O.sub.12, wherein RE is a mixture of ions of at least three rare-earth elements, optionally wherein up to about 10 atomic % of the RE ions are replaced by one or more activator ions of elements selected from Ce, Tb, Dy, Eu, Yb, and Pr. In some embodiments, the method comprises heating a mixture of raw materials (e.g., a mixture of metal oxides in a stoichiometric ratio depending upon the formula of the desired optical material) above their respective melting temperatures (i.e., above the melting temperature of the raw material with the highest melting temperature). In some embodiments, the raw materials are dried prior to, during, or after mixing. In some embodiments, the raw materials are mixed under low humidity and/or low oxygen conditions. In some embodiments, the raw materials are mixed in a dry box and/or under conditions of less than about 0.1 parts-per-million (ppm) moisture and/or oxygen (e.g., less than about 0.1 ppm, less than about 0.09 ppm, less than about 0.08 ppm, less than about 0.07 ppm, less than about 0.06 ppm, less than about 0.05 ppm, less than about 0.04 ppm, less than about 0.03 ppm, less than about 0.02 ppm, or less than about 0.01 ppm moisture and/or oxygen).
[0223] The mixture of raw materials can be sealed in a container (e.g., a quartz ampoule) that can withstand the subsequent heating of the mixture and which is chemically inert to the mixture of raw materials. The mixture can be heated at a predetermined rate to a temperature above the melting temperature of the individual raw materials. In some embodiments, the mixture can be heated to a temperature that is between about 10 C. and about 50 C. (e.g., about 10 C., about 12 C., about 14 C., about 16 C., about 18 C., about 20 C., about 22 C., about 24 C., about 26 C., about 28 C., about 30 C., about 32 C., about 34 C., about 36 C., about 38 C., about 40 C., about 42 C., about 44 C., about 46 C., about 48 C., or about 50 C.) above the melting temperature of the raw material with the highest melting temperature. In some embodiments, the mixture is heated to about 50 C. above the melting temperature of the raw material with the highest melting temperature. This temperature can be maintained for a period of time, such as between about 2 and about 36 hours (e.g., about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 14, about 16, about 18, about 20, about 22, about 24, about 26, about 28, about 30, about 32, about 34, or about 36 hours). In some embodiments, the temperature is maintained for about 24 hours. Then the mixture can be cooled at a predetermined rate until the mixture reaches about room temperature (e.g., between about 20 C. and about 25 C.). If desired, the sealed container can be rotated or inverted. In some embodiments, the heating and cooling can be repeated, e.g., to provide further mixing of all of the components in the mixture. The rotating or inverting and heating/cooling steps can be repeated one or more additional times, as desired.
[0224] In some embodiments, the method further comprises a post-growth annealing step. Thus, in some embodiments, the method further comprises annealing the optical material (e.g., the crystalline optical material). The annealing can be performed, for example, in air, nitrogen, or a mixture of nitrogen and hydrogen. The annealing can be done at any suitable temperature below the melting point of the optical material, e.g., between about 100 C. and about 1600 C. (e.g., about 100 C., about 200 C., about 300 C., about 400 C., about 500 C., about 600 C., about 700 C., about 800 C., about 900 C., about 1000 C., about 1100 C., about 1200 C., about 1300 C., about 1400 C., about 1500 C., and about 1600 C.).
[0225] In some embodiments, the optical (e.g., scintillation) materials can be provided as single crystals, as a polycrystalline material, and/or as a ceramic material. In some embodiments, the material is provided as a polycrystalline material. The polycrystalline material can have analogous physical, optical and scintillation properties as a single crystal otherwise having the same chemical composition.
[0226] In some embodiments, the presently disclosed subject matter provides a method of preparing an optical material of the presently disclosed subject matter, i.e., comprising or consisting of a composition of the formula:
##STR00003##
wherein: 0y0.1; 0z1; RE is a combination of ions of three or more rare-earth elements selected from the group comprising Y, Sc, Lu, Yb, Tm, Er, Ho, Dy, Tb, Gd, Eu, Sm, Nd, Pr, and La; and X is one or more activator ions selected from the group comprising a Ce ion, a Tb ion, a Dy ion, a Eu ion, a Yb ion, and a Pr ion, wherein the method comprises: [0227] (a) preparing a single crystal of the optical material from a melt (e.g., as described above); [0228] (b) preparing a powder of the optical material by: (i) preparing a foam by heating an aqueous solution comprising a polymer (e.g., polyvinyl alcohol (PVA) or polyethylene glycol (PEG)), and a mixture of metal nitrates, wherein the metal nitrates comprise ions of elements that correspond to elements of the optical material, and crushing said foam to provide the powder; or (ii) coprecipitating powder by adding an aqueous solution comprising a mixture of metal nitrates and ammonium sulfate to an aqueous solution of ammonium carbonate, wherein the metal nitrates comprise ions of elements that correspond to elements of the optical material; or [0229] (c) preparing a ceramic of the optical material by a technique selected from the group comprising sintering, hot pressing, hot isotactic pressing, and spark plasma synthesis (e.g., using binary oxides as starting materials).
[0230] Thus, in some embodiments, the optical material is provided as a powder (e.g., a green body powder). In some embodiments, the powder can be prepared by preparing a foam and then crushing the foam (e.g., the dehydrated foam) to provide the powder. For example, in some embodiments, the foam can be prepared by heating an aqueous solution comprising a polymer and a mixture of metal nitrates that comprise ions of elements that correspond to the elements in the desired optical material. In some embodiments, the polymer is PVA or PEG. In some embodiments, the polymer is PVA. In some embodiments, preparing the foam further comprises heating the aqueous solution to evaporate the water from the aqueous solution. In some embodiments, the foam can be further dehydrated in an oven for a period of time to remove residual moisture. In some embodiments, the foam can be placed in an oven at about 180 C. for about 2 hours. In some embodiments, the method further comprises calcining the powder in air (e.g., at about 650 C. for about 2.5 hours) to remove nitrates and polymer (e.g., PVA). In some embodiments, the powder can be crystallized. Crystallizing can be performed in air for a period of time (e.g., about 1 hour) at a temperature of about 900 C. to about 1300 C.
[0231] Alternatively, the powder can be prepared via coprecipitation. For example, in some embodiments, the method comprises coprecipitating the powder by adding an aqueous solution comprising a mixture of metal nitrates and ammonium sulfate to an aqueous solution of ammonium carbonate, wherein the metal nitrates comprise ions of elements that correspond to elements of the optical material. The precipitate that falls outs of solution can be collected via filtration. As with the powder prepared via a foam, in some embodiments the initially precipitated powder can be calcined. In some embodiments, the powder can be crystallized (e.g., in air at a temperature of about 900 C. to about 1300 C.).
[0232] In some embodiments, a mixture of metal oxides comprising metal elements corresponding to the desired rare-earth garnet can be mixed and ground in a mortar, and then pressed into pellets.
[0233] In some embodiments, the presently disclosed subject matter provides a method of preparing a ceramic of an optical material as described herein, wherein the method comprises performing a technique selected from the group comprising hot pressing, hot isotactic pressing, and spark plasma synthesis. In some embodiments, the method comprises use of binary oxides as the starting materials for the ceramic. For instance, in some embodiments, the annealing can comprise grinding a stoichiometric mixture of binary oxides, pressing the mixture to form a pellet, and annealing the pellet at a temperature of about 1500 C. for a period of time (e.g., about 10 hours). In some embodiments, a stoichiometric mixture of binary oxide powders or a rare-earth garnet powder can be hot-pressed at a temperature of about 1000 C. to about 2000 C. at about 5 MPa to about 100 MPa for a period of time (e.g., about 2 hours).
EXAMPLES
[0234] The following examples are included to further illustrate various embodiments of the presently disclosed subject matter. However, those of ordinary skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the presently disclosed subject matter.
Example 1
Powder Synthesis
Polymer Synthesis Route:
[0235] Metal nitrates were dissolved in a beaker of deionized (DI) water and polyvinyl alcohol (PVA, 9k-10k g/mol, 80% hydrolyzed) was dissolved in a different beaker of DI water. Once both solutions were dissolved, they were mixed and heated on a hotplate to evaporate the water producing a foam. The foam was placed in an oven for 2 hours at 180 C. to remove residual moisture. The powder produced by crushing the dehydrated foam was calcined at 650 C. in air for 2.5 hours to remove nitrates and PVA. The resulting powder was crystallized in air for 1 hour at temperatures varying between 900-1300 C. The result is a multi-component rare-earth garnet powder.
Coprecipitation Route:
[0236] Metal nitrates and ammonium sulfate were dissolved in a beaker of DI water and ammonium carbonate was dissolved in a separate beaker of DI water. The nitrate solution was added dropwise into the carbonate solution forming precipitates. The precipitates were filtered out of the combined solution and calcined at 650 C. in air for 2.5 hours. The resulting powder was crystallized in air for 1 hour at temperatures varying between 900-1300 C. The result is a multi-component rare-earth garnet powder.
Example 2
Synthesis of Ceramics
[0237] Ceramics can be prepared from a multi-component rare-earth garnet powder prepared in Example 1 or from binary oxide powders with at least 99.99% purity that were dried at 800 C. for 5 h in air.
Annealing:
[0238] Stoichiometric mixtures of the dried powders were ground in an agate mortar and pressed into pellets with 13 mm diameter. The pellets were sintered at 1500 C. for 10 h in air.
Hot-Pressing:
[0239] Stoichiometric binary oxide powders or multi-component rare-earth garnet powders were pressed into pellets with 13 mm diameter. The resulting green body pellet was hot-pressed at temperatures of 1400-1500 C. at 5-10 MPa for 2 hours.
Example 3
Synthesis of Single Crystals
[0240] Stoichiometric mixtures of the dried powders were mixed by manual agitation in 4 ml glass vials. Cylindrical single crystals with 3 mm in diameter were grown using a KDN Dai-Ichi Kiden micro-pulling-down furnace (Dai-Ichi Kiden Co., Ltd., Tokyo, Japan) equipped with a radiofrequency (RF) generator model TR-02001 operated at 26 kilovolt-amps (kVA). A 16 mm iridium crucible with a 3 mm die and a 0.5 mm capillary channel was used as a melt reservoir. Growth was initiated by touching the outlet of the capillary channel with a Czochralski-grown Lu.sub.3Al.sub.5O.sub.12 crystal seed. The RF generator power was ramped over a period of 2 hours to achieve the melting point, which was visually determined by probing the capillary with the seed and observing the presence of molten material. A charge-coupled device (CCD) camera was focused on the bottom of the crucible die to allow real time visualization of seeding and monitoring of the molten zone. The pulling rates used were in the range of 0.05-0.20 mm/min. After growth was finished, the RF generator power ramp-down was conducted over a period of four hours. The resulting single crystals had good optical quality. Discs with a thickness of 1 mm were cut and polished for optical and scintillation characterization.
Example 4
Characterization of Rare-Earth Garnet Optical Materials
[0241] Photos of crystals, ceramics, and green bodies of materials of the presently disclosed subject matter are shown in
[0242] Specific examples of single crystals include, but are not limited to, the crystals reported in Table 1, below.
TABLE-US-00001 TABLE 1 Scintillations properties of multicomponent (RE.sub.1-xCe.sub.x).sub.3Al.sub.5O.sub.12 Light Max output radioluminescence Composition (ph/MeV) (nm) (Y.sub.1/3Tb.sub.1/3Gd.sub.1/3).sub.3Al.sub.5O.sub.12:Ce 0.5% 7700 553 (Lu.sub.1/3Y.sub.1/3Gd.sub.1/3).sub.3Al.sub.5O.sub.12:Ce 0.5% 14800 564 (Lu.sub.1/3Y.sub.1/3Tb.sub.1/3).sub.3Al.sub.5O.sub.12:Ce 0.5% 14600 545 (Lu.sub.1/4Y.sub.1/4Tb.sub.1/4Gd.sub.1/4).sub.3Al.sub.5O.sub.12:Ce 0.5% 16700 560 (Lu.sub.1/4Y.sub.1/4Tb.sub.1/4Gd.sub.1/4).sub.3Al.sub.5O.sub.12: Ce 2% 13500 560
Structural Properties
[0243] Despite the complexity of the multicomponent compositions, powder X-ray diffraction (XRD) reveals a single cubic garnet structure with a space group Ia-3d. Examples of powder XRD patterns for the (RE.sub.1-xCe.sub.x).sub.3Al.sub.5O.sub.12 crystals are presented in
Optical and Scintillation Properties
[0244] Photoluminescence (PL) spectra were acquired with a Hitachi Fluorescence Spectrophotometer (Hitachi, Tokyo, Japan) equipped with a Xenon lamp at room temperature. The spectra shown in
[0245] Radioluminescence (RL) spectra were measured at room temperature under continuous irradiation from a X-ray generator model CMX003 (32 kV and 0.1 mA). A monochromator sold under the tradename PI Acton SPECTRAPRO SP-2155 (Telecyne Digital Imaging U.S. Inc., Thousand Oaks, California, United States of America) was used to record the spectra. The most intense emission bands in radioluminescence spectra shown in the
[0246] Absolute light output of the crystal samples was obtained by measuring pulse height spectra, which are presented in
Additional Compositions
[0247] The data in Table 2 was collected from green body pellets of additional exemplary rare-earth garnets. RL spectra determined for both Ce-doped and undoped compositions exhibit scintillation emission. See
TABLE-US-00002 TABLE 2 Radioluminescence and structural properties of the green body pellets. Peak RL Phase Theoretical wavelength pure density Composition (nm) garnet (g/cm.sup.3) (Y.sub.0.2Gd.sub.0.2Tb.sub.0.2Yb.sub.0.2Lu.sub.0.2).sub.3Al.sub.5O.sub.12 550 Yes 5.936 (Y.sub.0.199Gd.sub.0.199Tb.sub.0.199Yb.sub.0.199Lu.sub.0.199Ce.sub.0.005).sub.3Al.sub.5O.sub.12 551 Yes 5.940 (Y.sub.0.25Gd.sub.0.25Er.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12 555 Yes 5.867 (Y.sub.0.24875Gd.sub.0.24875Er.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12 558 Yes 5.866 (Y.sub.0.25Gd.sub.0.25Ho.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12 320 Yes 5.839 (Y.sub.0.24875Gd.sub.0.24875Ho.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12 569 Yes 5.840 (Y.sub.0.2Gd.sub.0.2Tb.sub.0.2Dy.sub.0.2Lu.sub.0.2).sub.3Al.sub.5O.sub.12 554 Yes 5.885 (Y.sub.0.199Gd.sub.0.199Tb.sub.0.199Dy.sub.0.199Lu.sub.0.199Ce.sub.0.005).sub.3Al.sub.5O.sub.12 558 Yes 5.884 (Y.sub.0.25Gd.sub.0.25Tb.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12 557 Yes 5.779 (Y.sub.0.24875Gd.sub.0.24875Tb.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12 553 Yes 5.775 (Y.sub.0.2Eu.sub.0.2Gd.sub.0.2Yb.sub.0.2Lu.sub.0.2).sub.3A.sub.15O.sub.12 603 Yes 5.893 (Y.sub.0.199Eu.sub.0.199Gd.sub.0.199Yb.sub.0.199Lu.sub.0.199Ce.sub.0.005).sub.3Al.sub.5O.sub.12 606 Yes 5.903 (Y.sub.0.1667Eu.sub.0.1667Gd.sub.0.1667Tb.sub.0.1667Yb.sub.0.1667Lu.sub.0.1667).sub.3Al.sub.5O.sub.12 603 Yes 5.912 (Y.sub.0.16583Eu.sub.0.16583Gd.sub.0.16583Tb.sub.0.16583Yb.sub.0.16583Lu.sub.0.16583Ce.sub.0.005).sub.3Al.sub.5O.sub.12 601 Yes 5.906 (Y.sub.0.25Sm.sub.0.25Gd.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12 618 Yes 5.698 (Y.sub.0.24875Sm.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12 613 Yes 5.700 (Y.sub.0.25Nd.sub.0.25Gd.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12 423 Yes 5.668 (Y.sub.0.24875Nd.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12 558 Yes 5.670 (Y.sub.0.25Pr.sub.0.25Gd.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12 623 Yes 5.602 (Y.sub.0.24875Pr.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12 571 Yes 5.605 (Y.sub.0.25La.sub.0.25Gd.sub.0.25Lu.sub.0.25).sub.3Al.sub.5O.sub.12 320 No 5.733 (Y.sub.0.24875La.sub.0.24875Gd.sub.0.24875Lu.sub.0.24875Ce.sub.0.005).sub.3Al.sub.5O.sub.12 574 No 5.737 (Y.sub.0.245Gd.sub.0.245Tb.sub.0.245Lu.sub.0.245Ce.sub.0.02).sub.3Al.sub.5O.sub.12 565 Yes 5.813 (Y.sub.0.2375Gd.sub.0.2375Tb.sub.0.2375Lu.sub.0.2375Ce.sub.0.05).sub.3Al.sub.5O.sub.12 582 No 5.808 (Y.sub.0.163Gd.sub.0.163Tb.sub.0.49Lu.sub.0.163Ce.sub.0.02).sub.3Al.sub.5O.sub.12 588 No 5.892 (Y.sub.0.294Gd.sub.0.294Tb.sub.0.098Lu.sub.0.294Ce.sub.0.02).sub.3Al.sub.5O.sub.12 565 Yes 5.767
REFERENCES
[0248] All references listed herein including but not limited to all patents, patent applications and publications thereof, scientific journal articles, and database entries are incorporated herein by reference in their entireties to the extent that they supplement, explain, provide a background for, or teach methodology, techniques, and/or compositions employed herein. [0249] [1] Euler, F.; Bruce, J. A., Oxygen Coordinates of Compounds with Garnet Structure. Acta Crystallogr 1965, 19, 971-978. [0250] [2] Nikl, M.; Yoshikawa, A.; Kamada, K.; Nejezchleb, K.; Stanek, C. R.; Mares, J. A.; Blazek, K., Development of LuAG-based scintillator crystalsA review. Prog Cryst Growth Ch 2013, 59 (2), 47-72. [0251] [3] Su, X.; Zhang, K.; Liu, K.; Zhong, H.; Shi, Y.; Pan, Y., Combinatorial Optimization of (Lu1-xGdx)3Al5O12:Ce3y Yellow Phosphors as Precursors for Ceramic Scintillators. ACS Comb. Sci. 2011, 13, 79-83. [0252] [4] Li, J.; Li, J. G.; Liu, S.; Li, X.; Sun, X.; Sakka, Y., The development of Ce3+-activated (Gd, Lu)3Al5O12 garnet solid solutions as efficient yellow-emitting phosphors. Sci. Technol. Adv. Mater. 2013 14 054201 99 pp. [0253] [5] Hu, S.; Qin, X.; Zhou, G.; Lu, C.; Guanghui, L.; Xu, Z.; Wang, Z., Luminescence characteristics of the Ce3+-doped garnets: the case of Gd-admixed Y3Al5O12 transparent ceramics. Opt. Mater. Express 2015 5 12. [0254] [6] Shao, C.; Zhang, L.; Zhou, T.; Gu, L.; Sun, B.; Jiang, Z.; Yao, Q.; Bu, W.; Wang, K.; Chen, H., Gd2O3 assisted densification of high quantity (Y, Gd)AG: Ce ceramic solidsolutions and their luminescence characteristics. Ceram. Int. 2018 44 8672-8678. [0255] [7] Boukerika, A.; Guerbous, L.; Belamri, M., Effect of Y3+ substitution on structural and photoluminescence properties of solid solutions [(Lu1xYx)1z Cez]3Al5O12 phosphors. Mater. Chem. Phys. 2016 171 394-399. [0256] [8] Yadav, S. K.; Uberuaga, B. P.; Nikl, M.; Jianng, C.; Stanek, C. R., Band-Gap and Band-Edge Engineering of Multicomponent Garnet Scintillators from First Principles. Phys. Rev. Applied. 2015 4 054012. [0257] [9] Dorenbos, P., Electronic structure and optical properties of the lanthanide activated RE3(Al1-xGax)5O12(RE=Gd, Y, Lu) garnet compounds. Journal of Luminescence. 2013 134 310-318.
[0258] It will be understood that various details of the presently disclosed subject matter may be changed without departing from the scope of the presently disclosed subject matter. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation.