A calcium metaborate birefringent crystal and a preparation method and use thereof, the crystal having a chemical formula of CaB.sub.2O.sub.4 and a molecular weight of 125.70, and belonging to the orthorhombic crystal system and space group Pbcn with unit-cell parameters a=11.60(4), b=4.28(8), c=6.21(6), and Z=4, wherein the calcium metaborate birefringent crystal is a negative biaxial crystal with a transmission range of 165-3400 nm and a birefringence between 0.09-0.36; the crystal is applicable to infrared-visible-ultraviolet-deep ultraviolet bands, and is grown by a melt method, a flux method, a Bridgman method or a heat exchange method; the crystal obtained by the method of the present invention is easy to grow and easy to process; and can be used for making polarizing beam-splitting prisms.

Disclosed are a yttrium-doped barium fluoride crystal and a preparation method and the use thereof, wherein the yttrium-doped barium fluoride crystal has a chemical composition of Ba.sub.(1x)Y.sub.xF.sub.2+x, in which 0.01x0.50. The yttrium-doped BaF.sub.2 crystal of the present invention has improved scintillation performance. The yttrium doping may greatly suppress the slow luminescence component of the BaF.sub.2 crystal and has an excellent fast/slow scintillation component ratio. The doped crystal is coupled to an optical detector to obtain a scintillation probe which is applicable to the fields of high time resolved measurement radiation such as high-energy physics, nuclear physics, ultrafast imaging and nuclear medicine imaging.

Disclosed are a yttrium-doped barium fluoride crystal and a preparation method and the use thereof, wherein the yttrium-doped barium fluoride crystal has a chemical composition of Ba.sub.(1x)Y.sub.xF.sub.2+x, in which 0.01x0.50. The yttrium-doped BaF.sub.2 crystal of the present invention has improved scintillation performance. The yttrium doping may greatly suppress the slow luminescence component of the BaF.sub.2 crystal and has an excellent fast/slow scintillation component ratio. The doped crystal is coupled to an optical detector to obtain a scintillation probe which is applicable to the fields of high time resolved measurement radiation such as high-energy physics, nuclear physics, ultrafast imaging and nuclear medicine 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.

An indium phosphide crystal substrate has a diameter of 100-205 mm and a thickness of 300-800 m and includes any of a flat portion and a notch portion. In any of a first flat region and a first notch region, when an atomic concentration of sulfur is from 2.010.sup.18 to 8.010.sup.18 cm.sup.3, the indium phosphide crystal substrate has an average dislocation density of 10-500 cm.sup.2, and when an atomic concentration of tin is from 1.010.sup.15 to 4.010.sup.18 cm.sup.3 or an atomic concentration of iron is from 5.010.sup.15 to 1.010.sup.17 cm.sup.3, the indium phosphide crystal substrate has an average dislocation density of 500-5000 cm.sup.2.

A method of making a component includes depositing a metallic powder on a workplane; directing a beam from a directed energy source to fuse the powder in a pattern corresponding to a cross-sectional layer of the component; repeating in a cycle the steps of depositing and fusing to build up the component in a layer-by layer fashion; and during the cycle of depositing and melting, using an external heat control apparatus separate from the directed energy source to maintain a predetermined temperature profile of the component, such that the resulting component has a directionally-solidified or single-crystal microstructure.

A method of making a component includes depositing a metallic powder on a workplane; directing a beam from a directed energy source to fuse the powder in a pattern corresponding to a cross-sectional layer of the component; repeating in a cycle the steps of depositing and fusing to build up the component in a layer-by layer fashion; and during the cycle of depositing and melting, using an external heat control apparatus separate from the directed energy source to maintain a predetermined temperature profile of the component, such that the resulting component has a directionally-solidified or single-crystal microstructure.

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.