The present disclosure discloses, in one arrangement, a scintillator material made of a metal halide with one or more additional group-13 elements. An example of such a compound is Ce:LaBr.sub.3 with thallium (Tl) added, either as a codopant or in a stoichiometric admixture and/or solid solution between LaBr.sub.3 and TlBr. In another arrangement, the above single crystalline iodide scintillator material can be made by first synthesizing a compound of the above composition and then forming a single crystal from the synthesized compound by, for example, the Vertical Gradient Freeze method. Applications of the scintillator materials include radiation detectors and their use in medical and security imaging.

The present disclosure relates to a process for fabricating a crystalline scintillator material with a structure of elpasolite type of theoretical composition A.sub.2BC.sub.(1-y)M.sub.yX.sub.(6-y) wherein: A is chosen from among Cs, Rb, K, Na; B is chosen from among Li, K, Na; C is chosen from among the rare earths, Al, Ga; M is chosen from among the alkaline earths, X is chosen from among F, Cl, Br, I; y representing the atomic fraction of substitution of C by M and being in the range extending from 0 to 0.05, comprising its crystallization by cooling from a melt bath comprising r moles of A and s moles of B, the melt bath in contact with the material containing A and B in such a way that 2s/r is above 1. The process shows an improved fabrication yield. Moreover, the crystals obtained can have compositions closer to stoichiometry and have improved scintillation properties.

The present disclosure relates to a process for fabricating a crystalline scintillator material with a structure of elpasolite type of theoretical composition A.sub.2BC.sub.(1-y)M.sub.yX.sub.(6-y) wherein: A is chosen from among Cs, Rb, K, Na; B is chosen from among Li, K, Na; C is chosen from among the rare earths, Al, Ga; M is chosen from among the alkaline earths, X is chosen from among F, Cl, Br, I; y representing the atomic fraction of substitution of C by M and being in the range extending from 0 to 0.05, comprising its crystallization by cooling from a melt bath comprising r moles of A and s moles of B, the melt bath in contact with the material containing A and B in such a way that 2s/r is above 1. The process shows an improved fabrication yield. Moreover, the crystals obtained can have compositions closer to stoichiometry and have improved scintillation properties.

A crystal growth furnace comprising a crucible containing at least feedstock material and a liquid-cooled heat exchanger that is vertically movable beneath the crucible to extract heat from it to promote the growth of a crystalline ingot is disclosed. The liquid-cooled heat exchanger comprises a heat extraction bulb made of high thermal conductivity material that is vertically movable into thermal communication with the crucible to extract heat from the crucible using a liquid coolant. A liquid-cooled heat exchanger enclosed in a sealed tubular outer jacket is also disclosed as is a method for producing a crystalline ingot using a vertically movable liquid-cooled heat exchanger.

A crystal growth furnace comprising a crucible containing at least feedstock material and a liquid-cooled heat exchanger that is vertically movable beneath the crucible to extract heat from it to promote the growth of a crystalline ingot is disclosed. The liquid-cooled heat exchanger comprises a heat extraction bulb made of high thermal conductivity material that is vertically movable into thermal communication with the crucible to extract heat from the crucible using a liquid coolant. A liquid-cooled heat exchanger enclosed in a sealed tubular outer jacket is also disclosed as is a method for producing a crystalline ingot using a vertically movable liquid-cooled heat exchanger.

Provided are a high resistance CdTe-based compound single crystal with miniaturized Te precipitates and a method for producing the same. According to one embodiment of the present invention, a CdTe based compound single crystal is provided including a precipitate having a particle size of less than 0.1 m obtained from an analysis by a light scattering tomography method. In the CdTe based compound single crystal, resistivity may be 110.sup.7 cm or more. In addition, in the CdTe based compound single crystal, a precipitate having a particle size of 0.1 m or more obtained from the analysis by the light scattering tomography method is not detected. In the CdTe based compound single crystal, the precipitate may be a Te precipitate.

Provided are a high resistance CdTe-based compound single crystal with miniaturized Te precipitates and a method for producing the same. According to one embodiment of the present invention, a CdTe based compound single crystal is provided including a precipitate having a particle size of less than 0.1 m obtained from an analysis by a light scattering tomography method. In the CdTe based compound single crystal, resistivity may be 110.sup.7 cm or more. In addition, in the CdTe based compound single crystal, a precipitate having a particle size of 0.1 m or more obtained from the analysis by the light scattering tomography method is not detected. In the CdTe based compound single crystal, the precipitate may be a Te precipitate.

An object is to provide a SiC wafer in which a detection rate of an optical sensor can improved and a SiC wafer manufacturing method. The method includes: a satin finishing process S141 of satin-finishing at least a back surface 22 of a SiC wafer 20; an etching process 21 of etching at least the back surface 22 of the SiC wafer 20 by heating under Si vapor pressure after the satin finishing process S141; and a mirror surface processing process S31 of mirror-processing a main surface 21 of the SiC wafer 20 after the etching process S21. Accordingly, it is possible to obtain a SiC wafer having the mirror-finished main surface 21 and the satin-finished back surface 22.

An object is to provide a SiC wafer in which a detection rate of an optical sensor can improved and a SiC wafer manufacturing method. The method includes: a satin finishing process S141 of satin-finishing at least a back surface 22 of a SiC wafer 20; an etching process 21 of etching at least the back surface 22 of the SiC wafer 20 by heating under Si vapor pressure after the satin finishing process S141; and a mirror surface processing process S31 of mirror-processing a main surface 21 of the SiC wafer 20 after the etching process S21. Accordingly, it is possible to obtain a SiC wafer having the mirror-finished main surface 21 and the satin-finished back surface 22.

The present invention relates to a substrate-triggered single crystal superalloy directional solidification process, including: (1) preparing a single crystal substrate material having crystallographic characteristics that match crystallographic characteristics of the single crystal superalloy; (2) fabricating a single crystal substrate chilling plate using the obtained single crystal substrate material; and (3) applying the obtained single crystal substrate chilling plate in a directional solidification apparatus, and then preparing a single crystal alloy product by performing superalloy melting and directional solidification. Compared with grain selector method and seeding with grain selector method, in addition to control the crystallographic orientation of the single crystal superalloy precisely, the present invention could reduce the height of block and the whole mold through canceling the spiral grain selector, significantly improve the axial heat dissipation and temperature gradient at the solid-liquid interface, and then reduce the occurrence of freckles and stray grains near platform.