Abstract: The invention is concerned with a material which shows low absorption for UV radiation having a wavelength below 250 nm, low birefringence, high chemical resistance and high radiation resistance and which is therefore particularly usable for making optical components for microlithography. According to the invention the material consists of synthetically produced quartz crystallites which form a polycrystalline structure and have a mean grain size in the range between 500 nm and 30 ?m. The method according to the invention for making a blank from the material comprises providing granules consisting of synthetically produced quartz crystals having a mean grain size in the range between 500 nm and 30 ?m, and sintering the granules to obtain a blank of polycrystalline quartz.

Abstract: The invention relates to a method for the economic production of a blank for a component made from laser-active quartz glass in any form or dimension. The method comprises the following method steps: a) preparation of a dispersion with a solids content of at least 40 wt. %, comprising SiO2 nanopowder and doping agents, including a cation of the rare earth metals and transition metals in a fluid, b) granulation by agitation of the dispersion, with removal of moisture to form a doped SiO2 granulate of spherical porous granular particles with a moisture content of less than 35 wt. % and a density of at least 0.95 g/cm3, c) drying and purification of the SiO2 granulate, by heating to a temperature of at least 1000° C. to form doped porous SiO2 grains with an OH content of less than 10 ppm and d) sintering or fusing the doped SiO2 grains in a reducing atmosphere to give the blank made from doped quartz glass.

Abstract: Starting from an optical component of quartz glass for transmitting ultraviolet radiation of a wavelength between 190 nm and 250 nm, with a glass structure essentially without oxygen defects, a hydrogen content ranging from 0.1×1016 molecules/cm3 to 5.0×1016 molecules/cm3, and with a content of SiH groups of less than 5×1016 molecules/cm3, to provide such a component which is particularly well suited for use with linearly polarized UV laser radiation, the present invention suggests that the component should have a content of hydroxyl groups ranging from 10 to 250 wt ppm and a fictive temperature above 1000° C.

Abstract: To provide an optical component of quartz glass for use in a projection lens system for immersion lithography with an operating wavelength below 250 nm, which is optimized for use with linearly polarized UV laser radiation and particularly with respect to compaction and birefringence induced by anisotropic density change, it is suggested according to the invention that the quartz glass should show the combination of several properties: particularly a glass structure essentially without oxygen defects, a mean content of hydroxyl groups of less than 60 wt ppm, a mean content of fluorine of less than 10 wt ppm, a mean content of chlorine of less than 1 wt ppm. A method for producing such an optical component comprises the following method steps: producing and drying an SiO2 soot body under reducing conditions and treating the dried soot body before or during vitrification with a reagent reacting with oxygen defects of the quartz glass structure.

Abstract: To optimize an optical component of synthetic quartz glass, in the case of which a quartz glass blank is subjected to a multistage annealing treatment, with respect to compaction and central birefringence, the present invention suggests a method comprising the following steps: (a) a first treatment phase during which the quartz glass blank is treated in an upper temperature range between 1130° C. and 1240° C., (b) cooling the quartz glass blank at a first-higher-mean cooling rate to a quenching temperature below 1100° C., a fictive temperature with a high mean value of 1100° C. or more being reached in the quartz glass, (c) a second treatment phase which comprises cooling of the quartz glass blank at a second-lower-mean cooling rate, and in which the quartz glass blank is treated in a lower temperature range between 950° C. and 1100° C. such that a fictive temperature is reached in the quartz glass with a low mean value which is at least 50° C.

Abstract: The present invention relates to a quartz glass blank for an optical component for transmitting radiation of a wavelength of 15 nm and shorter, the blank consisting of highly pure quartz glass, doped with titanium and/or fluorine, which is distinguished by an extremely high homogeneity. The homogeneity relates to the following features: a) micro-inhomogeneities caused by a local variance of the TiO2 distribution (<0.05% TiO2, averaged over a volume element of (5 ?m)3 in relation to the mean value of the TiO2 content), b) an absolute maximum inhomogeneity in the thermal expansion coefficient ?? in the main functional direction (<5 ppb/K), c) a radial variance of the thermal expansion coefficient over the usable surface of the quartz glass blank of not more than 0.4 ppb/(K·cm); d) a maximum stress birefringence (SDB) at 633 nm in the main functional direction of 2 nm/cm with a specific progression; and e) a specific progression of the ??, averaged according to (b) on the optical surface.

Abstract: An ideal quartz glass for a wafer jig for use in an environment having an etching effect is distinguished by both high purity and high resistance to dry etching. To indicate a quartz glass that substantially fulfills these requirements, it is suggested according to the invention that the quartz glass is doped with nitrogen at least in a near-surface area, has a mean content of metastable hydroxyl groups of less than 30 wt ppm and that its fictive temperature is below 1250° C. and its viscosity is at least 1013 dPa·s at a temperature of 1200° C. An economic method for producing such a quartz glass comprises the following method steps: melting an SiO2 raw material to obtain a quartz glass blank, the SiO2 raw material or the quartz glass blank being subjected to a dehydration measure, heating the SiO2 raw material or the quartz glass blank to a nitriding temperature in the range between 1050° C. and 1850° C.

Abstract: In a known method, a quartz glass component is produced for a UV radiation source by melting SiO2-containing grain. Starting therefrom, to indicate an inexpensive method by means of which a quartz glass component is obtained that is characterized by high radiation resistance, it is suggested according to the invention that synthetically produced quartz crystals are molten to obtain a pre-product which consists of quartz glass containing hydroxyl groups in a number greater than the number of SiH groups, and that for the elimination of SiH groups the pre-product is subjected to an annealing treatment at a temperature of at least 850° C., whereby the quartz glass component is obtained. In the quartz glass component of the invention, the quartz glass is molten from synthetically produced quartz crystals, and it has a content of SiH groups of less than 5×1017 molecules/cm3.

Abstract: A known method for producing synthetic quartz glass with a predetermined hydroxyl group content comprises the following steps: a porous SiO2 soot body is produced by flame hydrolysis or oxidation of a silicon-containing start compound and by layerwise deposition of SiO2 particles on a rotating support; the soot body is subjected to a dehydration treatment in a reaction gas-containing drying atmosphere at a drying temperature for removing hydroxyl groups; and the SiO2 soot body is vitrified into a body consisting of the synthetic quartz glass. Starting from this, and in order to permit a reproducible and reliable manufacture of synthetic, UV-radiation resistant quartz glass with predetermined hydroxyl group content and low chlorine content, it is suggested according to the invention that the dehydration treatment according to method step (b) comprises a drying phase during which ozone is used as the reaction gas, whereby the ozone content of the drying atmosphere is between 0.5% by vol. and 10% by vol.

Abstract: The invention is concerned with a material which shows low absorption for UV radiation having a wavelength below 250 nm, low birefringence, high chemical resistance and high radiation resistance and which is therefore particularly usable for Making optical components for microlithography. According to the invention the material consists of synthetically produced quartz crystallites which form a polycrystalline structure and have a mean grain size in the range between 500 nm and 30 ?m. The method according to the invention for making a blank from the material comprises providing granules consisting of synthetically produced quartz crystals having a mean grain size in the range between 500 nm and 30 ?m, and sintering the granules to obtain a blank of polycrystalline quartz.

Abstract: The invention relates to a method for the economic production of a blank for a component made from laser-active quartz glass in any form or dimension. The method comprises the following method steps: a) preparation of a dispersion with a solids content of at least 40 wt. %, comprising SiO2 nanopowder and doping agents, including a cation of the rare earth metals and transition metals in a fluid, b) granulation by agitation of the dispersion, with removal of moisture to form a doped SiO2 granulate of spherical porous granular particles with a moisture content of less than 35 wt. % and a density of at least 0.95 g/cm3, c) drying and purification of the SiO2 granulate, by heating to a temperature of at least 1000° C. to form doped porous SiO2 grains with an OH content of less than 10 ppm and d) sintering or fusing the doped SiO2 grains in a reducing atmosphere to give the blank made from doped quartz glass.

Abstract: An agricultural machine having at least one crop processing work unit, a plurality of crop transport units operatively assembled as a straw walker step, wherein the crop transport units convey crop streams in opposite directions and are spaced apart defining a crop through-gap, and a cleaning device having a forced-draught fan before the cleaning device, further comprising an exhaust fan located after the cleaning device, wherein the transport units are located between the forced-draught fan and the exhaust fan, wherein an air stream is produced by the forced-draught fan and the exhaust fan and is directed from the forced-draught fan to the exhaust fan, and wherein the air stream improves a cleaning process in the straw walker through-gap of the straw walker step.

Abstract: To provide an optical component of quartz glass for use in a projection lens system for immersion lithography with an operating wavelength below 250 nm, which is optimized for use with linearly polarized UV laser radiation and particularly with respect to compaction and birefringence induced by anisotropic density change, it is suggested according to the invention that the quartz glass should show the combination of several properties: particularly a glass structure essentially without oxygen defects, a mean content of hydroxyl groups of less than 60 wt ppm, a mean content of fluorine of less than 10 wt ppm, a mean content of chlorine of less than 1 wt ppm. A method for producing such an optical component comprises the following method steps: producing and drying an SiO2 soot body under reducing conditions and treating the dried soot body before or during vitrification with a reagent reacting with oxygen defects of the quartz glass structure.

Abstract: The present invention relates to a quartz glass blank for an optical component for transmission of ultraviolet radiation of a wavelength of 250 nm or shorter, and to a use of the quartz glass blank in microlithography in combination with ultraviolet radiation of a wavelength of 250 nm or shorter. Moreover, the invention relates to a procedure for manufacture of the quartz glass blank. A quartz glass blank of the described type should show little induced absorption and be optimized with respect to compaction and decompaction. The quartz glass blank according to the invention is characterized by the following properties: a glass structure essentially free of oxygen defect sites, an H2-content in the range of 0.1×1016 molecules/cm3 to 4.0×1016 molecules/cm3, an OH-content in the range of 125 wt-ppm to 450 wt-ppm, an SiH group-content of less than 5×1016 molecules/cm3, a refractive index inhomogeneity, ?n, of less than 2 ppm, and a stress birefringence of less than 2 nm/cm.

Abstract: The present invention relates to a quartz glass blank for an optical component for transmission of ultraviolet radiation of a wavelength of 250 nm or shorter, and to a use of the quartz glass blank in microlithography in combination with ultraviolet radiation of a wavelength of 250 nm or shorter. Moreover, the invention relates to a procedure for manufacture of the quartz glass blank. A quartz glass blank of the described type should show little induced absorption and be optimized with respect to compaction and decompaction. The quartz glass blank according to the invention is characterized by the following properties: a glass structure essentially free of oxygen defect sites, an H2-content in the range of 0.1×1016 molecules/cm3 to 4.0×1016 molecules/cm3, an OH-content in the range of 125 wt-ppm to 450 wt-ppm, an SiH group-content of less than 5×1016 molecules/cm3, a refractive index inhomogeneity, ?n, of less than 2 ppm, and a stress birefringence of less than 2 nm/cm.

Abstract: The present invention concerns a quartz glass blank for an optical component for the transmission of ultraviolet radiation of a wave length of 250 nm and under, as well as its utilization in microlithography in connection with ultraviolet radiation of a wavelength of 250 nm and under. Such quartz glass blank is to have low induced absorption, while being optimized in respect of compaction and de-compaction. The quartz glass blank according to the invention has the following properties: A glass structure essentially free of oxygen defect sites; a H2 content in the range of 3×1017 molecules/cm3 to 2.0×1018 molecules/cm3; an OH content in the range of 500 weight ppm to 1000 weight ppm; a SiH group content of less than 2×1017 molecules/cm3; a chlorine content in the range of 60 weight ppm to 120 weight ppm; a refractive index inhomogeneity, ?n, of less than 2 ppm; and a stress birefringence of less than 2 nm/cm.

Abstract: An agricultural machine having at least one crop processing work unit, a plurality of crop transport units operatively assembled as a straw walker step, wherein the crop transport units convey crop streams in opposite directions and are spaced apart defining a crop through-gap, and a cleaning device having a forced-draught fan before the cleaning device, further comprising an exhaust fan located after the cleaning device, wherein the transport units are located between the forced-draught fan and the exhaust fan, wherein an air stream is produced by the forced-draught fan and the exhaust fan and is directed from the forced-draught fan to the exhaust fan, and wherein the air stream improves a cleaning process in the straw walker through-gap of the straw walker step.

Abstract: An agricultural harvesting machine has a comminuting device which includes a chopper rotor having a rotor shaft, and a conveying element pivotably connected with the rotor shaft. The conveying element is formed by a first arm and a second arm which are interconnected by a cross web. In one embodiment the cross web has a recess between the first and second arms, and a cutting element is provided which passes either through the recess of the conveying element or outside of the first and second arms of conveying element as the conveying element rotates. In another embodiment the conveying element is provided with both leading and trailing cutting edges arranged in sets. Initially one set of cutting edges is utilized and the conveying element can latter be reversed in position to utilize the other set.

Abstract: A harvesting machine having a dividing device for dividing granular material from stem- or stalk-like material, and a separating device connected downstream of the dividing device, in which there is a conveying unit for conveying the stream of material from the dividing device to the separating device. In order to satisfactorily discharge the stem- or stalk-like material from the conveying tines of the conveying unit, cleaning elements are provided for cleaning away the material being conveyed over the free ends of the conveying tines.