Ternary metal halide scintillators

Abstract

Metal halide scintillators are described. More particularly, the scintillators include doped (e.g., europium-doped) ternary metal halides, such as those of the formulas A 2 BX 4 and AB 2 X 5 , wherein A is an alkali metal, such as Li, Na, K, Rb, Cs or any combination thereof; B is an alkali earth metal, such as Be, Mg, Ca, Sr, Ba or any combination thereof; and X is a halide, such as Cl, Br, I, F or any combination thereof. Radiation detectors comprising the novel metal halide scintillators and other ternary metal halides, such as those of the formulas A 2 EuX 4 and AEu 2 X 5 , wherein A is an alkali metal and X is a halide, are also described.

What is claimed is: 
     
         1 . A scintillator material comprising one of Formulas (I), (II), (III), (IV), (V), or (VI):
   A 2 B (1-y) L y X 4    (I),
     AB 2(1-y) L 2y X 5    (II);
     A′ 2(1-y) L′ 2y BX 4    (III);
     A′ (1-y) L′ y B 2 X 5    (IV),
     A″ 2(1-y) L″ 2y BX 4    (V); or
     A″ (1-y) L″ y B 2 X 5    (VI);
   
       wherein:
 0.0001≤y≤0.5; 
 A is one or more alkali metal; 
 A′ is one or more of the group consisting of Li, K, Rb, and Cs; 
 A″ is Na or a combination of Na and one or more additional alkali metal; 
 B is one or more alkali earth metal; 
 L is selected from the group consisting of Eu, Ce, Tb, Yb, and Pr; 
 L′ is selected from the group consisting of Tl, In, and Na; 
 L″ is selected from the group consisting of Tl and In; and 
 X is one or more halide. 
 
     
     
         2 . The scintillator material of  claim 1 , wherein A or A′ is selected from K, Rb, and Cs. 
     
     
         3 . The scintillator material of  claim 1 , wherein B is selected from Sr and Ba. 
     
     
         4 . The scintillator material of  claim 1 , wherein X is selected from Cl, Br, and I. 
     
     
         5 . The scintillator material of  claim 1 , wherein L is Eu and the scintillator material comprises A 2 B (1-y) Eu y X 4  or AB 2(1-y) Eu 2y X 5 . 
     
     
         6 . The scintillator material of  claim 1 , wherein 0.01≤y≤0.1. 
     
     
         7 . The scintillator material of  claim 6 , wherein 0.025≤y≤0.05. 
     
     
         8 . The scintillator material of  claim 7 , comprising A 2 B 0.95 Eu 0.05 X 4  or AB 2(0.975) Eu 2(0.025) X 5 . 
     
     
         9 . The scintillator material of  claim 7 , wherein the scintillator material is selected from the group consisting of K 2 BaI 4 :Eu 5%; K 2 BaBr 4 :Eu 5%; Rb 2 BaCl 4 :Eu 5%; K 2 SrBr 4 :Eu 5%; Rb 2 BaCl 4 :Eu 2.5%; RbSr 2 Cl 5 :Eu 2.5%; KSr 2 Br 5 :Eu 2.5%; KBa 2 I 5 :Eu 2.5%; CsSr 2 I 5 :Eu 2.5%; RbBa 2 Br 5 :Eu 2.5%; RbSr 2 Br 5 :Eu 2.5%; KSr 2 I 5 :Eu 4%; and KSr 2 I 5 :Eu 2.5%. 
     
     
         10 . A radiation detector comprising a photon detector and a scintillation material, wherein the scintillation material comprises a scintillator material of  claim 1 . 
     
     
         11 . The radiation detector of  claim 10 , wherein the detector is a medical diagnostic device, a device for oil exploration, or a device for container or baggage scanning. 
     
     
         12 . 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 10 . 
     
     
         13 . A radiation detector comprising a photon detector and a scintillation material, wherein the scintillation material comprises one of Formulas (I′), (II′), (III′), (IV′), (V′), or (VI′):
   A 2 B (1-z) L z X 4    (I′);
 
   AB 2(1-z) L 2z X 5    (II′);
 
   A′ 2(1-z) L′ 2z BX 4    (III′);
 
   A′ (1-z) L′ z B 2 X 5    (IV′);
 
   A″ 2(1-z) L″ 2z BX 4    (V′); or
 
   A″ (1-z) L″ z B 2 X 5    (VI′);
 
 
       wherein:
 0.0001≤z≤1.0; 
 A is one or more alkali metal; 
 A′ is one or more of the group consisting of Li, K, Rb, and Cs; 
 A″ is Na or a combination of Na and one or more additional alkali metal; 
 B is one or more alkali earth metal; 
 L is selected from the group consisting of Eu, Ce, Tb, Yb, and Pr; 
 L′ is selected from the group consisting of Tl, In, and Na; 
 L″ is selected from the group consisting of Tl and In; and 
 X is one or more halide. 
 
     
     
         14 . The radiation detector of  claim 13 , wherein A or A′ is selected from K, Rb, and Cs. 
     
     
         15 . The radiation detector of  claim 13 , wherein B is selected from Sr and Ba. 
     
     
         16 . The radiation detector of  claim 13 , wherein X is selected from Cl, Br, and I. 
     
     
         17 . The radiation detector of  claim 13  wherein L is Eu and the scintillator material comprises A 2 B (1-z) Eu z X 4  or AB 2(1-z) Eu 2z X 5 . 
     
     
         18 . The radiation detector of  claim 13 , wherein 0.01≤z≤0.1. 
     
     
         19 . The radiation detector of  claim 13 , wherein 0.025≤z≤0.05. 
     
     
         20 . The radiation detector of  claim 13 , wherein the scintillation material comprises A 2 B 0.95 Eu 0.05 X 4  or AB 2(0.975) Eu 2(0.025) X 5 . 
     
     
         21 . The radiation detector of  claim 13 , wherein the scintillation material is selected from the group consisting of K 2 BaI 4 :Eu 5%; K 2 BaBr 4 :Eu 5%; Rb 2 BaCl 4 :Eu 5%; K 2 SrBr 4 :Eu 5%; Rb 2 BaCl 4 :Eu 2.5%; RbSr 2 Cl 5 :Eu 2.5%; KSr 2 Br 5 :Eu 2.5%; KBa 2 I 5 :Eu 2.5%; CsSr 2 I 5 :Eu 2.5%; RbBa 2 Br 5 :Eu 2.5%; RbSr 2 Br 5 :Eu 2.5%; KSr 2 I 5 :Eu 4%; and KSr 2 I 5 :Eu 2.5%. 
     
     
         22 . The radiation detector of  claim 13 , wherein z is 1. 
     
     
         23 . The radiation detector of  claim 22 , wherein the scintillation material is K 2 EuCl 4  or RbEu 2 Cl 5 . 
     
     
         24 . The radiation detector of  claim 13 , wherein the detector is a medical diagnostic device, a device for oil exploration, or a device for container or baggage scanning. 
     
     
         25 . 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 . 
     
     
         26 . A method of preparing a scintillator material of  claim 1 , wherein the method comprises heating a mixture of raw materials above their respective melting temperatures. 
     
     
         27 . The method of  claim 26 , wherein the method comprises:
 (a) providing a mixture of raw materials, wherein the raw materials are provided in a stoichiometric ratio according to one of the formulas of  claim 1 ;   (b) sealing said mixture in a sealed container;   (c) heating the mixture to about 20° C. above the melting point of the raw material having the highest melting point for a period of time;   (d) cooling the mixture to about room temperature; and   (e) optionally repeating steps (c) and (d).   
     
     
         28 . The method of  claim 26 , wherein the scintillator material is prepared in polycrystalline form.