Abstract: A method of producing bi-modal particles includes the steps of igniting a first precursor gas using a primary burner thereby producing a first plurality of particles of a first size, fluidly transporting the first plurality of particles down a particle tube, igniting a second precursor gas using a secondary burner thereby producing a second plurality of particles of a second size, flowing the second plurality of particles into the first plurality of particles, and capturing the first and second plurality of particles.

Abstract: Provided is a transparent structure having improved wear resistance and flexibility, and a structure according to the present invention is a nanolayered structure in which a nitride nanofilm of one or more elements selected from metals and metalloids; and a boron nitride nanofilm are alternately layered.

Abstract: A method for manufacturing a porous glass fine particle body including: forming a deposit layer of glass fine particles, generated from raw material gas including a silicon-containing organic compound, on a rotary starting member; supplying the raw material gas to a burner; switching the raw material gas to purge gas; supplying the purge gas to the burner at a first flow rate when the raw material gas is discharged from inside the burner; and switching the first flow rate to a second flow rate smaller than the first flow rate.

Abstract: Apparatus and methods of for measuring stress incurred by a cover glass of a handheld device when the cover glass contacts a surface during a drop event. A transparent solid piece of material with a drop surface and a back surface is provided and oriented to receive a dropped handheld device so that the cover glass contacts the drop surface. At least two optical detectors are directed at the back surface of the transparent material to obtain image data including a plurality of pixel points.

Abstract: A method of forming an optical fiber preform includes the steps: igniting a burner having a fume tube assembly to produce a first spray size of silicon dioxide particles; depositing the silicon dioxide particles on a core cane to produce a soot blank; and adjusting an effective diameter of an aperture of the fume tube assembly to produce a second spray size of the silicon dioxide particles. The second spray size is larger than the first spray size.

Abstract: A method for producing synthetic fused quartz is provided. The method includes evaporating a feedstock material which contains at least one polymerizable polyalkylsiloxane compound, and supplying the feedstock material vapor to a reaction zone, wherein the feedstock material vapor is converted by oxidation and/or by hydrolysis into SiO2 particles. The feedstock material vapor is passed through a membrane filter as a cleaning device to reduce the formation of gel, which is typically associated with the production of synthetic fused quartz.

Abstract: Systems, interfaces, and methods for implementing the systems and interfaces includes selection attractive movement as the selection protocol, where a selection object is used to discriminate between selectable objects and attract a target object toward the selection objects, where the direction and speed of the motion controls, discriminates, attracts, and activates the selected objects.

Abstract: An apparatus including a movement sensor and processing unit, where sensed movement, especially velocity and/or acceleration and changes thereof, is used to control real and/or virtual objects, where no hard selection protocol is used and output signals and/or commands occur with a change in velocity or acceleration.

Abstract: A quartz glass tube as a semi-finished product for an optical component that has an inner bore extending along a tube center axis for the acceptance of a core rod and a tube wall limited by an inner casing surface and an outer casing surface is already known; within said tube wall an inner region made of a first quartz glass and an outer region made of a second quartz glass with a different index of refraction surrounding the inner region contact one another at a contact surface which runs around the center axis. In order to provide a quartz glass on this basis that facilitates the production of optical components for special applications such as laser-activated optical components in wand or fiber form, the invention states that the contact surface has a non-round course in the radial cross-section and the inner casing surface has a circular course.

Abstract: Provided is a method for manufacturing an optical fiber preform. In a premixing step, a source-material-containing gas containing organosilicon is mixed with premix-use oxygen gas so as to obtain a premixed source material gas. In the premixing step, the premix-use oxygen gas has a temperature greater than or equal to a liquefaction temperature of the organosilicon, the liquefaction temperature being determined depending on an amount of the organosilicon contained in the premixed source material gas.

Abstract: A method for manufacturing an SiO2—TiO2 based glass upon a target by a direct method, includes: an ingot growing step of growing an SiO2—TiO2 based glass ingot having a predetermined length on the target by flame hydrolysis by feeding a silicon compound and a titanium compound into an oxyhydrogen flame, wherein the ingot growing step includes: a first step of increasing a ratio of a feed rate of the titanium compound to a feed rate of the silicon compound as the SiO2—TiO2 based glass ingot grows until the ratio reaches a predetermined value; and a second step of gradually growing the SiO2—TiO2 based glass ingot after the ratio has reached the predetermined value in the first stage with keeping the ratio within a predetermined range.

Abstract: A method of making an optical fiber preform comprising in order: (i) manufacturing a glass preform with at least one porous layer; (ii) exposing the glass preform with at least one porous layer to a fluorine precursor at temperature below 1295° C. to make a fluorine treated preform, and (iii) exposing the fluorine treated glass preform with at least one porous silica based layer the temperatures above 1400° C. to completely sinter the preform. Preferably, the porous silica based layer of the glass preform exposed to fluorine precursor has average density of at least 0.7 g/cm3 but less than 1.9 g/cm3.

Abstract: An optical member including a porous glass layer on a base member is provided, wherein the reflectance is reduced and a ripple is suppressed. The optical member is provided with a base member and a glass layer holding a transparent material in the inside of a porous structure disposed on the base member, wherein in the thickness direction of the glass layer, the porosity in the base member side with respect to the center line of the glass layer in the thickness direction is smaller than the porosity in the side opposite to the base member with respect to the center line of the glass layer in the thickness direction.

Abstract: A sintering apparatus for sintering a porous glass base material, including a furnace core tube surrounded by heaters, the furnace core tube housing the porous glass base material; a lid member having an insertion hole through which a holding rod coupled with the porous glass base material is inserted, the lid member mounted at one end of the furnace core tube; a sealing chamber having a supply port that introduces seal gas and a discharging port that discharges the seal gas, the sealing chamber provided at the lid member covering the insertion hole; and a cylindrical member that causes a pressure difference between gas inside of the tube of an inside the furnace core tube and gas inside of the sealing chamber to be generated while the holding rod is inserted through the cylindrical member inside of the sealing chamber.

Abstract: An electrical switch apparatus including a movement sensitive form is disclosed. The apparatus includes a housing, a motion sensor and a processing unit, where motion on, near or about the motion sensor is translated into output commands adapted for list scrolling, where the list can be arranged in a hierarchy such as menus or for changing a value of an attribute of an electrical device under the control of the switch.

Abstract: To reduce scratches during polishing while ensuring an appropriately high polishing rate, provided are a silica for CMP satisfying the following (A) to (C), an aqueous dispersion using a silica for CMP, and a method of producing a silica for CMP: (A) a BET specific surface area of 40 m2/g or more and 180 m2/g or less; (B) a particle density measured by a He-gas pycnometer method of 2.24 g/cm3 or more; and (C) a coefficient of variation in primary particle diameter calculated by TEM/image analysis of 0.40 or less.

Abstract: A glass article for use in Extreme Ultra-Violet Lithography (EUVL) is provided. The glass article includes a silica-titania glass having a compositional gradient through the glass article, the compositional gradient being defined by the functions: [TiO2]=(c+f(x,y,z)), and [SiO2]=(100?{c+f(x,y,z)}??(x,y,z)) wherein [TiO2] is the concentration of titania in wt. %, [SiO2] is the concentration of silica in wt. %, c is the titania concentration in wt. % for a predetermined zero crossover temperature (Tzc), f(x, y, z) is a function in three-dimensional space that defines the difference in average composition of a volume element centered at the coordinates (x, y, z) with respect to c, and ?(x, y, z) is a function in three-dimensional space that defines the sum of all other components of a volume element centered at the coordinates (x, y, z).

Abstract: A method for manufacturing an SiO2—TiO2 based glass upon a target by a direct method, includes a first process of preheating the target and a second process of growing an SiO2—TiO2 based glass ingot to a predetermined length upon the target which has been preheated, wherein the target is heated in the first process such that, in the second process, the temperature of growing surface of the glass ingot is maintained at or above a predetermined lower limit temperature.

Abstract: The invention relates to a method for producing synthetic quartz glass by vaporizing a polyalkylsiloxane as a liquid SiO2 feedstock (105), converting the vaporized SiO2 feedstock (107) into SiO2 particles, separating the SiO2 particles, forming a soot body (200) and vitrifying the soot body (200). According to the invention, the vaporizing of the heated SiO2 feedstock (105) comprises an injection phase in an expansion chamber (125), in which the SiO2 feedstock (105) is atomized into fine droplets, wherein the droplets have an average diameter of less than 5 pm, and wherein the atomizing of the droplets takes place in a preheated carrier gas stream which has a temperature of more than 180° C.

Abstract: Producing a silica container includes forming a powder mixture by adding an Al compound or a crystal nucleating agent into a first powdered raw material; preliminarily molding to an intended shape by feeding the powder mixture to an inner wall of an outer frame while rotating the outer frame having aspiration holes; forming a silica substrate; and forming a transparent silica glass layer on an inner surface of the silica substrate, wherein the preliminarily molded article is degassed by aspiration from a peripheral side and heated from inside the preliminarily molded article at high temperature making a peripheral part of the preliminarily molded article to a sintered body while an inner part to a fused glass body, and a second powdered raw material having a higher silica purity than the first powdered raw material is spread from inside the silica substrate and heated from the inside at high temperature.

Abstract: A method for producing a silica container includes forming a preliminarily molded substrate, wherein a first powdered raw material is fed to an inner wall of an outer frame having aspiration holes while rotating the outer frame; forming a preliminarily molded intermediate layer, wherein a second powdered raw material added with an aluminum compound or a crystal nucleating agent as an additive is fed to an inner wall of the preliminarily molded substrate; and forming an inner layer, wherein the preliminarily molded substrate and the preliminarily molded intermediate layer are degassed by aspiration from a peripheral side with heating from an inside forming a substrate and an intermediate layer, and a third powdered raw material having a high silica purity is spread from inside the substrate having the formed intermediate layer with heating from the inside forming an inner layer on an inner surface of the intermediate layer.

Abstract: Common solar radiation receivers are equipped with a chamber for transmission of an operating gas which is directed along to an absorber for solar radiation for thermal absorption. The absorber has a dome-shaped entry window made of quartz glass, wherein the inner side facing the absorber assumes a nominal interior temperature Ti of at least 950° C. during proper use, preferably at least 1000° C., whereas the outer side facing away from the absorber is exposed to the environment and subject to risk of devitrification. The invention relates to modifying the known solar radiation receiver so that a high absorber temperature can be set and thus a high efficiency of the solar thermal heating is enabled, without increasing the risk of devitrification in the region of the outer side of the entry window.

Abstract: A process is disclosed for simple and rapid production of a shaped body comprising fused silica and a shaped body which leads to virtually no contamination of a melt in contact with the shaped body even at high temperatures. The disclosed process comprises the steps of: a) provision of fused silica in the form of essentially amorphous SiO2 grains of which not more than 5% have a diameter greater than 15 mm, b) addition of water to the fused silica grains to produce a slip, c) casting of the slip into a mold which comprises a hollow body having the inverse shape of the shaped body to be produced, and d) drying of the slip to give an intermediate body, which is then sintered and cooled. A shaped body producible in accordance with the aforementioned process is also disclosed, which comprises at least 99.0 mol % of SiO2.

Abstract: A burner module comprising a burner gas inlet block, a lower flow plate, an upper flow plate, a burner gas flow disperser, and a burner gas discharge block. The burner gas inlet block, the burner gas flow disperser, and the burner gas discharge block each comprising a plurality of channels separated by partitions. The partitions of the burner gas flow disperser and the burner gas discharge block comprising a knife edge. The upper flow plate and the lower flow plate each comprising a plurality of pressure holes in fluid communication with the plurality of channels. Additionally, the method of forming a glass sheet or ribbon using the disclosed burner module and a glass sheet or ribbon formed using the method.

Abstract: A glass, glass-ceramic, or ceramic bead is described, with an internal porous scaffold microstructure that is surrounded by an amorphous shield. The shield serves to protect the internal porous microstructure of the shield while increasing the overall strength of the porous microstructure and improve the flowability of the beads either by themselves or in devices such as biologically degradable putty that would be used in bone or soft tissue augmentation or regeneration. The open porosity present inside the bead will allow for enhanced degradability in-vivo as compared to solid particles or spheres and also promote the growth of tissues including but not limited to all types of bone, soft tissue, blood vessels, and nerves.

Abstract: The present invention provides a method of manufacturing a vitreous silica crucible including: a silica powder supplying process of supplying a material silica powder into a mold for molding a crucible, to form a silica powder layer, and an arc fusing process of arc fusing the silica powder layer by arc discharge generated by carbon electrodes, wherein the arc fusing process includes processes of measuring a temperature of the silica powder layer, and controlling a vitreous silica fused state based on a reference temperature which is a temperature at a local maximum point which appears first in the arc fusing process.

Abstract: A near-net or net shape fused silica glass article, such as a radome. The article is formed by depositing silica soot onto a mandrel having a shape that corresponds to the shape of the fused silica glass article. In some embodiments, the mandrel is inductively heated to a temperature that is sufficient to consolidate or sinter the silica soot upon deposition onto the mandrel to form fused silica glass. The fused silica glass article may have an outer layer that is under compression and/or multiple layers comprising various dopants that can alter or affect physical, mechanical, electrical, and/or optical properties.

Abstract: Provided is a method for manufacturing a vitreous silica crucible and a manufacturing apparatus for the same, which can reduce the amount of bubbles and impurities of a crucible inner surface and enhance a crystallization yield of silicon single crystal. A method for manufacturing a vitreous silica crucible of the invention includes a silica powder supplying process of supplying silica powder in a rotating mold to form a silica powder layer; an arc fusing process of fusing the silica powder layer by arc discharge generated by carbon electrodes; and a fire polishing process of throwing an arc flame toward a target surface of the silica powder layer for surface removal, wherein, in the fire polishing process, the distances from the tips of the carbon electrodes to the target surface is set to be equal.

Abstract: A method for producing a silica container, the method including forming a preliminarily molded silica substrate to an intended shape by feeding a powdered substrate's raw material (silica particles) to an inner wall of a carbon-made outer frame having aspiration holes with rotating the outer frame, and forming the silica substrate wherein the preliminarily molded substrate is degassed by aspiration from its outer peripheral side with charging from an inner peripheral side of the preliminarily molded silica substrate a reducing gas containing more than 10% by volume of an H2 gas, and at the same time heated from inside the preliminarily molded silica substrate by a discharge-heat melting method with carbon electrodes, thereby making an outer peripheral part of the preliminarily molded silica substrate to a sintered body while an inner peripheral part of the preliminarily molded silica substrate to a fused glass body.

Abstract: The present invention provides a method of manufacturing a vitreous silica crucible by heating and fusing a silica powder layer in a rotating mold by arc discharge generated by carbon electrodes comprising: a preparation process for determining optimal temperatures during heating and fusing the silica powder layer for one or more selected from the group consisting of the silica powder layer, fume generated during arc fusing, and arc flame generated in the arc discharge; a temperature measuring process for measuring actual temperatures during heating and fusing for one or more selected from the group where the optimal temperatures are determined; and a temperature controlling process for controlling the actual temperatures for one or more selected from the group where the actual temperatures are measured so that the actual temperatures match the optimal temperatures.

Abstract: The present invention provides a method of manufacturing a vitreous silica crucible including: a silica powder supplying process of supplying a material silica powder into a mold for molding a vitreous silica crucible, to form a silica powder layer, and an arc fusing process of arc fusing the silica powder layer by arc discharge generated by carbon electrodes, wherein the arc fusing process includes processes of measuring temperatures at measuring points provided on different heights of an inner surface of the silica powder layer while rotating the mold, and controlling the arc discharge to enable detection, at each measuring point, of a local maximum point which appears first in the arc fusing process.

Abstract: There is provided a method of manufacturing a vitreous silica crucible having non-bubbles on the inner surface without necessitating new apparatuses for grinding and polishing and without damaging the productivity. According to the present invention, there is provided a method of manufacturing a vitreous silica crucible including the processes of: gathering a vitreous silica layer containing residual bubbles existing in a near-surface region of the transparent layer of the vitreous silica crucible by controlling the number of rotations applied to the vitreous silica crucible in a state that an inner surface side of the vitreous silica crucible is fused by arc heating; and moving a portion of a non-bubble layer in the surface of the transparent layer exposed by movement of the residual bubble-containing layer to cover a region in which bubbles have gathered with the non-bubble layer.

Abstract: Synthetic quartz glass is prepared by subjecting a silicon-providing feedstock to flame hydrolysis in oxyhydrogen flame, depositing silica fine particles on a rotating quartz glass target while concurrently melting and vitrifying them, thereby forming a synthetic quartz glass ingot, shaping, annealing, and effecting dehydrogenation treatment at a temperature of at least 600° C. and a pressure of up to 5 Pa for a holding time of at least 12 hours. The synthetic quartz glass has a high helium gas permeability and is suited for forming nanoimprint molds.

Abstract: A method for manufacturing a silica glass crucible, includes: preparing a crucible base material that is made of silica glass and has a crucible shape; fabricating a synthetic silica glass material based on a direct method or a soot method; processing the synthetic silica glass material into the crucible shape without being pulverized; and bonding an inner wall of the crucible base material and an outer wall of the synthetic silica glass material processed into the crucible shape through a silica powder by performing a heat treatment. As a result, it is possible to provide the silica glass crucible that can avoid occurrence of dislocations of silicon single crystal at the time of manufacturing the silicon single crystal, has high heat-resisting properties, and can suppress a reduction in productivity and yield ratio, the manufacturing method thereof, and the method for manufacturing silicon single crystal using such a silica glass crucible.

Abstract: A burner module comprising a burner gas inlet block, a lower flow plate, an upper flow plate, a burner gas flow disperser, and a burner gas discharge block. The burner gas inlet block, the burner gas flow disperser, and the burner gas discharge block each comprising a plurality of channels separated by partitions. The partitions of the burner gas flow disperser and the burner gas discharge block comprising a knife edge. The upper flow plate and the lower flow plate each comprising a plurality of pressure holes in fluid communication with the plurality of channels. Additionally, the method of forming a glass sheet or ribbon using the disclosed burner module and a glass sheet or ribbon formed using the method.

Abstract: The present invention relates to a method for producing a silica glass body containing titania, containing: a flame hydrolysis step of feeding a silica (SiO2) precursor and a titania (TiO2) precursor into an oxyhydrogen flame and causing a hydrolysis reaction in the flame to form silica glass fine particles containing titania, in which in the flame hydrolysis step, a reaction rate of the hydrolysis reaction of the silica precursor is 80% or more.

Abstract: The present invention relates to a method for producing a glass body containing: hydrolyzing a silicon compound and a compound containing a metal serving as a dopant, in a flame projected from a burner to form glass fine particles; and depositing and growing the formed glass fine particles on a base material, in which a raw material mixed gas containing a gas of the silicon compound, a gas of the compound containing a metal serving as a dopant, and either one of a combustible gas and a combustion supporting gas is fed into a central nozzle (A) positioning in the center of the burner; the other gas of the combustible gas and the combustion supporting gas is fed into a nozzle (B) different from the central nozzle (A) of the burner; a combustible gas or a combustion supporting gas is arbitrarily fed into a nozzle different from the nozzles (A) and (B); and a flow rate of the raw material mixed gas is 50% or more and not more than 90% of the largest flow rate among flow rate(s) of the combustible gas(ses) and the

Abstract: A titania and sulfur co-doped quartz glass member is provided. Due to co-doping of titania and sulfur, the quartz glass member undergoes zero expansion at a certain temperature and low thermal expansion over a wide temperature range, and is thus suited for use in a commercial EUV lithography tool. A manufacturing method and an optical member for EUV lithography are also provided.

Abstract: The present invention relates to an optical member for deep ultraviolet having a wavelength of 250 nm or shorter, containing a synthetic silica glass which does not substantially contain a halogen element, has a maximum OH group content of less than 10 ppm by weight, has contents of ODC (oxygen deficient centers) and E-prime center of each less than 1×1014 cm?3, does not substantially contain SiH and peroxy linkage, and has a fictive temperature of 1,050° C. or lower.

Abstract: A method for producing a silica container includes forming a preliminarily molded substrate, wherein a first powdered raw material is fed to an inner wall of an outer frame having aspiration holes while rotating the outer frame; forming a preliminarily molded intermediate layer, wherein a second powdered raw material added with an aluminum compound or a crystal nucleating agent as an additive is fed to an inner wall of the preliminarily molded substrate; and forming an inner layer, wherein the preliminarily molded substrate and the preliminarily molded intermediate layer are degassed by aspiration from a peripheral side with heating from an inside forming a substrate and an intermediate layer, and a third powdered raw material having a high silica purity is spread from inside the substrate having the formed intermediate layer with heating from the inside forming an inner layer on an inner surface of the intermediate layer.

Abstract: Producing a silica container includes forming a powder mixture by adding an Al compound or a crystal nucleating agent into a first powdered raw material; preliminarily molding to an intended shape by feeding the powder mixture to an inner wall of an outer frame while rotating the outer frame having aspiration holes; forming a silica substrate; and forming a transparent silica glass layer on an inner surface of the silica substrate, wherein the preliminarily molded article is degassed by aspiration from a peripheral side and heated from inside the preliminarily molded article at high temperature making a peripheral part of the preliminarily molded article to a sintered body while an inner part to a fused glass body, and a second powdered raw material having a higher silica purity than the first powdered raw material is spread from inside the silica substrate and heated from the inside at high temperature.

Abstract: The production of synthetic quartz glass granules by vitrifying a free-flowing SiO2 granulate from porous granulate particles is time-consuming and expensive. The aim of the invention is to provide a method that allows a continuous and cost-effective production of dense synthetic quartz glass granules on the basis of porous SiO2 granulate. According to the invention, this is achieved by the following method steps: (a) granulating pyrogenically produced silicic acid with the formation of the SiO2 granulate made of porous granulate particles; (b) drying the SiO2 granulate; (c) cleaning the SiO2 granulate by heating in an atmosphere containing halogen in a cleaning furnace; and (d) vitrifying the cleaned SiO2 granulate by sintering in a vitrifying furnace with the formation of quartz glass granules. The drying, cleaning, and vitrifying of the SiO2 granulate are each carried out in a tary tube of a rotary tube furnace, said rotary tube rotating about a central axis.

Abstract: The present invention relates to a TiO2-containing quartz glass substrate, having a TiO2 concentration of from 3 to 8% by mass, an OH concentration of 50 ppm by mass or less, and an internal transmittance T365 per 1 mm thickness at a wavelength of 365 nm of 95% or more.

Abstract: Methods are described for manufacturing silica-based glass, in which silica precursor material is supplied to a synthesis flame in the form of an emulsion. The methods involve the steps of: forming an emulsion of an aqueous phase in a non-aqueous liquid silica precursor material; supplying the emulsion as a spray of droplets into a synthesis flame, whereby the precursor material is converted in the flame into a silica-containing soot; and collecting the soot on a substrate, either as a porous soot body for subsequent consolidation to glass or directly as a substantially pore-free glass.

Abstract: A glass sheet is formed using a roll-to-roll glass soot deposition and sintering process. The glass sheet formation involves forming a first glass soot layer on a deposition surface of a soot-receiving device, removing the first glass soot layer from the deposition surface, and forming a second glass soot layer on the unsupported first glass soot layer. The resulting composite glass soot sheet is heated to form a sintered glass sheet. The glass sheet can be a substantially homogeneous glass sheet or a composite glass sheet having layer-specific attributes.

Abstract: A method of producing a quartz glass crucible for pulling a single crystal comprising: providing a melting mold comprising a wall having passages between outside and inside; providing an outer layer granulation consisting of first coarser SiO2 particles and forming an outer granulation layer from the outer layer granulation on the inside of the melting mold wall; providing a barrier layer granulation consisting of second finer SiO2 particles and forming a barrier granulation layer from the barrier layer granulation on the outer granulation layer; applying a negative pressure to the outside of the melting mold wall; and heating the barrier granulation layer and the outer granulation layer with formation of a quartz glass crucible with transparent inner layer.

Abstract: It is an object of the present invention to provide a copper-containing silica glass which emits fluorescence having a peak in a wavelength range of from 520 nm to 580 nm under irradiation of ultraviolet light with a wavelength of 400 nm or less, and which is excellent in long term stability even in the high output use. The copper-containing silica glass is made to have copper of from 5 wtppm to 200 wtppm, which emits fluorescence having a peak in a wavelength range of from 520 nm to 580 nm under irradiation of ultraviolet light with a wavelength ranging from 160 nm to 400 nm, and in which an internal transmittance per 2.5 mm thickness at a wavelength of 530 nm is 95% or more.

Abstract: A method of producing a quartz glass crucible by arc melting a quartz powder molded product loaded on the inner side of a mold while performing vacuum suction, includes initiating the melting of quartz powder from the rim edge of a quartz powder molded product, subsequently lowering the arc electrode or raising the mold to heat and melt the sections on the downside of the rim edge. The method is preferably carried out such that the inner surface of the crucible is sealed within a time corresponding to 10% of the total arc time starting from the initiation of arc melting, and the seal thickness is 3 mm or less. The quartz glass crucible thus produced is useful for the pulling up of silicon single crystals and has a uniform glass layer with fewer internal bubbles.

Abstract: On an EUV light-reflecting surface of titania-doped quartz glass, an angle (?) included between a straight line connecting an origin (O) at the center of the reflecting surface to a birefringence measurement point (A) and a fast axis of birefringence at the measurement point (A) has an average value of more than 45 degrees. Since fast axes of birefringence are distributed in a concentric fashion, a titania-doped quartz glass substrate having a high flatness is obtainable which is suited for use in the EUV lithography.

Abstract: During fabrication of a vitreous silica crucible, contamination of the vitreous silica crucible due to wear particles and debris of components of an apparatus for manufacturing a vitreous silica crucible is reduced by preventing damage and wear of the components of the apparatus due to silica fume. The apparatus for manufacturing a vitreous silica crucible is divided into a lower section for accommodating a mold and a mold driving system and an upper section for accommodating an arc electrode driving system, wherein a sectioning member including one or more communication paths for allowing penetration of arc electrodes, thereby the air flow is controlled so as to reduce exchange between gas in the upper section and gas in the lower section.