The present invention relates to an apparatus and method for purifying materials using a rapid directional solidification. Devices and methods shown provide control over a temperature gradient and cooling rate during directional solidification, which results in a material of higher purity. The apparatus and methods of the present invention can be used to make silicon material for use in solar applications such as solar cells.

The present invention relates to an apparatus and method for purifying materials using a rapid directional solidification. Devices and methods shown provide control over a temperature gradient and cooling rate during directional solidification, which results in a material of higher purity. The apparatus and methods of the present invention can be used to make silicon material for use in solar applications such as solar cells.

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 method for minimizing unwanted ancillary reactions in a vacuum furnace used to process a material, such as growing a crystal. The process is conducted in a furnace chamber environment in which helium is admitted to the furnace chamber at a flow rate to flush out impurities and at a predetermined pressure to achieve thermal stability in a heat zone, to minimize heat flow variations and to minimize temperature gradients in the heat zone. During cooldown helium pressure is used to reduce thermal gradients in order to increase cooldown rates.

A method for minimizing unwanted ancillary reactions in a vacuum furnace used to process a material, such as growing a crystal. The process is conducted in a furnace chamber environment in which helium is admitted to the furnace chamber at a flow rate to flush out impurities and at a predetermined pressure to achieve thermal stability in a heat zone, to minimize heat flow variations and to minimize temperature gradients in the heat zone. During cooldown helium pressure is used to reduce thermal gradients in order to increase cooldown rates.

A process for fabricating a crystalline scintillator material with an elpasolite structure that has a theoretical composition of A.sub.2BC.sub.(1-y)M.sub.yX.sub.(6-y) can include conducting crystallization by cooling from a melt bath including r moles of A and s moles of B. A is chosen from Cs, Rb, K, and Na. B is chosen from Li, K, and Na. C is chosen from athe rare earth elements, Al, and Ga. M is chosen from the alkaline earth elements. X is chosen from F, Cl, Br, and I, and y represents the atomic fraction of substitution of C by M and is in the range extending from 0 to 0.05. The melt bath can be 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. The crystals formed therefrom can have improved scintillation properties.

A process for fabricating a crystalline scintillator material with an elpasolite structure that has a theoretical composition of A.sub.2BC.sub.(1-y)M.sub.yX.sub.(6-y) can include conducting crystallization by cooling from a melt bath including r moles of A and s moles of B. A is chosen from Cs, Rb, K, and Na. B is chosen from Li, K, and Na. C is chosen from athe rare earth elements, Al, and Ga. M is chosen from the alkaline earth elements. X is chosen from F, Cl, Br, and I, and y represents the atomic fraction of substitution of C by M and is in the range extending from 0 to 0.05. The melt bath can be 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. The crystals formed therefrom can have improved scintillation properties.

Disclosed is a method for preparing polycrystalline silicon ingot. The preparation method comprises: randomly laying seed crystals with unlimited crystal orientation at the bottom of crucible to form a layer of seed crystals and obtaining disordered crystalline orientations; providing molten silicon above the layer of seed crystals, controlling the temperature at the bottom of the crucible, making the layer of seed crystals not completely melted; controlling the temperature inside the crucible, making the molten silicon growing above the seed crystals, the molten silicon inheriting the structure of the seed crystals, then obtaining polycrystalline silicon ingot. By adopting the preparation method, a desirable initial nucleus can be obtained for a polycrystalline silicon ingot, so as to reduce dislocation multiplication during the growth of the polycrystalline silicon ingot.

A method includes grinding alumina powder into alumina particles with ultrafine particle powder, performing a purification process so that the alumina particles have a purity greater than 99.999%, processing the alumina particles by a spray dryer, processing the alumina particles by a sheet molding compound to produce an alumina material, and placing the alumina material in a vacuum super high temperature furnace to have a crystal growth which includes placing the alumina material in a predetermined crucible in the vacuum super high temperature furnace, preburning the alumina material to form a half-baked alumina cake, heating and increasing a temperature of the alumina cake so that the alumina cake is disposed at a melted state until the crystal growth is finished, and curing the alumina cake that is melted so as to form a sapphire crystal.