A method for producing Si ingot single crystal by NOC growth method including a Si ingot single crystal growing step and a continuous growing step is provided. The growing step includes providing a low temperature region in the Si melt where the Si ingot single crystal is grown along the surface of the Si melt or toward the inside of the Si melt, and the Si ingot single crystal has distribution of a vacancy concentration and an interstitial concentration in which respectively a vacancy concentration and an interstitial concentration vary with a distance from the growth interface; and adjusting a temperature gradient and a growth rate in the Si melt, so that along with the increasing of the distance from the growth interface, the vacancy concentration and the interstitial concentration in the Si ingot single crystal respectively decrease come near to each other.

The present disclosure provides a method for increasing luminescence uniformity and reducing afterglow of a Ce-doped gadolinium-aluminum-gallium garnet structure scintillation crystal, a crystal material and a detector. Sc ions are doped into the crystal material, and the Sc ions occupy at least an octahedral site. The effective segregation coefficient of active Ce ions is increased by a radius compensation effect of Sc—Ce ions and adjustment of lattice parameters, thereby the luminescence uniformity of the crystal is increased and the energy resolution is optimized; and at the same time, the potential barrier for Gd ions entering the octahedral site is increased, thereby the probability of the Gd ions entering the octahedral site is reduced, the density of point defects in the crystal is decreased, and the afterglow intensity is reduced. A general formula of the Ce-doped gadolinium-aluminum-gallium garnet structure scintillation crystal is {Gd.sub.1-x-y-pSc.sub.xCe.sub.yMe.sub.p}.sub.3[Al.sub.1-q].sub.5O.sub.12, 0<x≤0.1, 0<y<0.02, 0≤p≤0.02, 0.4≤q≤0.7.

A deposit removing device disclosed herein removes a deposit that adheres to an exhaust pipe through which gas is exhausted from a chamber that manufactures a semiconductor crystal. The deposit removing device includes: a valve that opens and closes an exhaust outlet that communicates with the exhaust pipe; a sealing cover and a fixed table configured to store the valve, into which an inert gas is introduceable, and configured to isolate the exhaust outlet from the outside; and an exhaust outlet opening/closing portion that includes a cylinder for driving the valve and a cylinder for driving the sealing cover or the fixed table. The cylinder drives the valve to open and close the exhaust outlet, and the cylinder drives the sealing cover or the fixed table to introduce the atmosphere into the sealing cover.

The present invention relates to a continuous ingot growing apparatus, and more specifically, to a continuous ingot growing apparatus which melts a solid silicon material supplied to a preliminary crucible to supply the solid silicon material to a main crucible and which can adjust a supply amount of molten silicon while blocking floating matter floating on top of the molten silicon so as not to be supplied.

Provided is a method for producing a lithium tantalate single crystal substrate capable of suppressing increase in volume resistivity of the lithium tantalate single crystal substrate owing to reduction failure even when a lithium carbonate power is repeatedly used in heat treatment for the lithium tantalate single crystal substrate. The invention is a method for producing a lithium tantalate single crystal substrate having a volume resistivity of 1×10.sup.10 Ω.Math.cm or more and less than 1×10.sup.12 Ω.Math.cm, including a step of heat-treating a lithium tantalate single crystal substrate having a volume resistivity of 1×10.sup.12 Ω.Math.cm or more and having a single-domain structure, under normal pressure and at a temperature of 350° C. or higher but not higher than the Curie temperature thereof while burying it in a lithium carbonate powder having a BET specific surface area of 0.13 m.sup.2/g or more, wherein the lithium carbonate powder is a used lithium carbonate powder that has been used in burying a lithium tantalate single crystal substrate in heat treatment for the lithium tantalate single crystal structure under normal pressure and at a temperature of 350° C. or higher but not higher than the Curie temperature thereof, and in the heat treatment step, the heat treatment is carried out in a mixed gas atmosphere of an inert gas and a reducing gas at the start of the heat treatment, and after the heat treatment in the mixed gas atmosphere, the heat treatment is carried out in a single gas atmosphere of an inert gas.

Provided is a method for producing a lithium tantalate single crystal substrate capable of suppressing increase in volume resistivity of the lithium tantalate single crystal substrate owing to reduction failure even when a lithium carbonate power is repeatedly used in heat treatment for the lithium tantalate single crystal substrate. The invention is a method for producing a lithium tantalate single crystal substrate having a volume resistivity of 1×10.sup.10 Ω.Math.cm or more and less than 1×10.sup.12 Ω.Math.cm, including a step of heat-treating a lithium tantalate single crystal substrate having a volume resistivity of 1×10.sup.12 Ω.Math.cm or more and having a single-domain structure, under normal pressure and at a temperature of 350° C. or higher but not higher than the Curie temperature thereof while burying it in a lithium carbonate powder having a BET specific surface area of 0.13 m.sup.2/g or more, wherein the lithium carbonate powder is a used lithium carbonate powder that has been used in burying a lithium tantalate single crystal substrate in heat treatment for the lithium tantalate single crystal structure under normal pressure and at a temperature of 350° C. or higher but not higher than the Curie temperature thereof, and in the heat treatment step, the heat treatment is carried out in a mixed gas atmosphere of an inert gas and a reducing gas at the start of the heat treatment, and after the heat treatment in the mixed gas atmosphere, the heat treatment is carried out in a single gas atmosphere of an inert gas.

An apparatus for manufacturing a single crystal according to a Czochralski method, including: a main chamber housing crucibles for a raw-material melt and heater for heating the raw-material melt; a pulling chamber at an upper portion of the main chamber and a single crystal pulled from the raw-material melt; a cooling cylinder extending from a ceiling portion of the main chamber toward a surface of the raw-material melt to surround the single crystal; an auxiliary cooling cylinder inside the cooling cylinder; and a diameter-enlargement member to fit into the auxiliary cooling cylinder. The auxiliary cooling cylinder has a slit penetrating in an axial direction to come into close contact with the cooling cylinder by pushing the diameter-enlargement member into the auxiliary cooling cylinder to enlarge the diameter of the auxiliary cooling cylinder. This enables efficient cooling of a growing single crystal and increases the growth rate of the single crystal.

The present invention relates to a premelter for pre-melting silicon before supplying to a main crucible capable of accurately measuring an input amount of molten silicon input into an ingot growth crucible, thereby effectively controlling the input amount, and a method for controlling the same. According to an embodiment of the present invention, disclosed is a premelter for pre-melting silicon before supplying to a main crucible, comprising: a preliminary crucible for supplying silicon in a molten state to a main crucible in which an ingot is grown after heating the silicon material in a solid state to become silicon in a molten state; a preliminary crucible moving module configured to tilt the preliminary crucible to one of a first position in which the preliminary crucible contains the solid silicon material or the molten silicon or a second position where the molten silicon in the preliminary crucible flows into the main crucible; and a control unit for controlling the preliminary crucible moving module.

A method for preparing a single crystal silicon ingot and a wafer sliced therefrom are provided. The ingots and wafers comprise nitrogen at a concentration of at least about 1×10.sup.14 atoms/cm.sup.3 and/or germanium at a concentration of at least about 1×10.sup.19 atoms/cm.sup.3, interstitial oxygen at a concentration of less than about 6 ppma, and a resistivity of at least about 1000 ohm cm.

A wavelength conversion member includes a sintered body of a phosphor. An average diameter of pores in an arbitrary cross section falls within a range of not less than 0.28 μm and not more than 0.98 μm. A ratio of an area of pores to a whole area in an arbitrary cross section falls within a range of not less than 0.04% and not more than 2.7%. An average diameter of grains of the phosphor in an arbitrary cross section falls within a range of not less than 1 μm and not more than 3 μm.