Method for purifying a thallium compound using a carbon powder

Abstract

Methods for purifying reaction precursors used in the synthesis of inorganic compounds and methods for synthesizing inorganic compounds from the purified precursors are provided. Also provided are methods for purifying the inorganic compounds and methods for crystallizing the inorganic compounds from a melt. γ and X-ray detectors incorporating the crystals of the inorganic compounds are also provided.

What is claimed is: 
     
         1 . A method of purifying a thallium-containing chalcogenide crystal or a thallium-containing halide crystal, the method comprising:
 loading a thallium-containing chalcogenide compound or a thallium-containing halide compound into a tube, wherein the thallium-containing chalcogenide compound or the thallium-containing halide compound comprises one or more impurity elements;   sealing the tube under vacuum;   mounting the sealed tube in a furnace;   melting and re-solidifying the thallium-containing chalcogenide compound or the thallium-containing halide compound to form a boule of the thallium-containing chalcogenide compound or the thallium-containing halide compound in the bottom of the tube;   forming a molten zone through a section of a bottom portion of the boule;   moving the molten zone vertically upward through the boule, while maintaining a solid plug of the thallium-containing chalcogenide compound or the thallium-containing halide compound above the molten zone as it moves vertically upward through the boule, to provide a purified boule;   discontinuing the upward motion of the molten zone before the molten zone reaches the top of the boule; and   melting at least a portion of the purified boule to form a melt and growing a crystal of the purified thallium-containing chalcogenide compound or thallium-containing halide compound from the melt via Bridgman growth.   
     
     
         2 . The method of  claim 1 , further comprising removing the lowermost portion of the purified boule prior to melting at least a portion of the purified boule. 
     
     
         3 . The method of  claim 1 , wherein the crystal of the purified thallium-containing chalcogenide compound or the crystal of the purified thallium-containing halide compound is a crystal of a purified thallium chalcohalide. 
     
     
         4 . The method of  claim 3 , wherein the thallium chalcohalide is Tl 6 SI 4 . 
     
     
         5 . The method of  claim 4 , wherein the one or more impurity elements include one or more of Li, Na, Si, P, V, Cr, Fe, Cu, Ge, Rb, Ag, Sn, Re, Pb, and Bi. 
     
     
         6 . The method of  claim 5 , wherein the one or more impurity elements include one or more of Na, Si, V, Fe, Cu, Rb, Sn, Pb, and Bi. 
     
     
         7 . The method of  claim 1 , wherein a strip heater is used to form the molten zone through the section of the bottom portion of the boule and to more the molten zone vertically upward through the boule. 
     
     
         8 . The method of  claim 3 , wherein the thallium chalcohalide is Tl 6 SeI 4 . 
     
     
         9 . The method of  claim 8 , wherein the one or more impurity elements include one or more of Si, Pb and Bi. 
     
     
         10 . The method of  claim 1 , wherein a concentration of one or more of the impurity elements in the crystal of the purified thallium-containing chalcogenide compound or the crystal of the purified thallium-containing halide compound is reduced by a factor of at least five, relative to a concentration of the one or more impurity elements in the thallium-containing chalcogenide compound or the thallium-containing halide compound loaded into the tube. 
     
     
         11 . The method of  claim 10 , wherein a concentration of one or more of the impurity elements in the crystal of the purified thallium-containing chalcogenide compound or the crystal of the purified thallium-containing halide compound is reduced by a factor of at least 100, relative to a concentration of the one or more impurity elements in the thallium-containing chalcogenide compound or the thallium-containing halide compound loaded into the tube. 
     
     
         12 . The method of  claim 10 , wherein the crystal of the purified thallium-containing chalcogenide compound or the crystal of the purified thallium-containing halide compound is a crystal of a purified thallium chalcohalide. 
     
     
         13 . The method of  claim 12 , wherein the thallium chalcohalide is Tl 6 SI 4 . 
     
     
         14 . The method of  claim 13 , wherein the one or more impurity elements include one or more of Li, Na, Si, P, V, Cr, Fe, Cu, Ge, Rb, Ag, Sn, Re, Pb, and Bi. 
     
     
         15 . The method of  claim 14 , wherein the one or more impurity elements include one or more of Na, Si, V, Fe, Cu, Rb, Sn, Pb, and Bi. 
     
     
         16 . The method of  claim 12 , wherein the thallium chalcohalide is Tl 6 SeI 4 . 
     
     
         17 . The method of  claim 16 , wherein the one or more impurity elements include one or more of Si, Pb, and Bi.