Nano-scale metal oxyhalide and oxysulfide scintillation materials and methods for making same

Abstract

Crystalline scintillator materials comprising nano-scale particles of metal oxides, metal oxyhalides and metal oxysulfides are provided. The nano-scale particles are less than 100 nm in size. Methods are provided for preparing the particles. In one method, used to form oxyhalides and oxysulfides, metal salts are dissolved in water, and then precipitated out as fine particles using an aqueous base. After the particles are separated from the solution, they are annealed under a flow of a water saturated hydrogen anion gas, such as HCl or H 2 S, to form the crystalline scintillator particles The other methods take advantage of the characteristics of microemulsion solutions to control droplet size, and, thus, the particle size of the final nano-particles. For example, in one method, a first micro-emulsion containing metal salts if formed. The first micro-emulsion is mixed with an aqueous base in a second micro-emulsion to form the final nano-scale particles.

1 .- 34 . (canceled) 
     
     
         35 . A method for making nano-scale particles of an oxyhalide or oxysulfide type scintillation material, comprising:
 adding an aqueous base to an aqueous solution comprising one or more metal salts to precipitate a gel containing the one or more metal salts;   removing free ions from the gel;   heating the gel; and   drying the gel to form the nano-scale particles of the oxyhalide or oxysulfide type scintillation material.   
     
     
         36 . The method of  claim 35  wherein the one or more metal salts comprise at least one metal anion selected from the group consisting of lanthanoids, group 2 elements, group 3 elements, group 13 elements, group 14 elements, group 15 elements, and combinations thereof. 
     
     
         37 . The method of  claim 35  wherein the one or more metal salts comprise at least one metal anion selected from the group consisting of lanthanum, cerium, terbium, thallium, gadolinium, europium, and combinations thereof. 
     
     
         38 . The method of  claim 35  wherein the aqueous base comprises NH4OH. 
     
     
         39 . The method of  claim 35  wherein drying the gel comprises heating the gel in a water-saturated atmosphere of an anion source gas. 
     
     
         40 . The method of  claim 35  wherein the anion source gas comprises at least one of H2S, HCl, HBr, HI, or HF. 
     
     
         41 . The method of  claim 35  wherein the oxyhalide or oxysulfide based scintillation material comprises a phosphor having a general formula of LaO(I, Br, Cl, or F):Tb. 
     
     
         42 . The method of  claim 35  wherein the nano-scale particles of the oxyhalide or oxysulfide based scintillater material are less than about 100 nm in size. 
     
     
         43 - 57 . (canceled)