Abstract: Disclosed is a scanner for the scanning of articles including a scanning apparatus (10) having a scanning device (18) and a rotatable sample mount (14,420) whereby, the scanning device and mount are relatively displaceable along the rotary axis (48) of the mount, a receptacle (40,140,240,400) mounted on the sample mount, the receptacle being capable of securely accommodating an article (30), and an actuator (146,246) for linearly displacing the receptacle whereby, actuation of the actuator displaces the receptacle and any article secured thereto, with respect to the sample mount. The article may be elongate and the displacement by the actuator is along an axis defined by the elongate axis of the elongate article. Also disclosed is a method of scanning.

Abstract: A device for the axial and rotational movement of a sample is disclosed comprising a mount member for mounting the sample, which is rotatable about and movable along an axis, characterised in that the mount member has a helical screw thread which produces the movement along said axis simultaneously with the rotation. A sample may be scanned or machined whilst being axially and rotationally moved. The screw thread may be disengageable perphaps by relative movement of co-operating screw threads into and out of engagement with each other by a lever to allow movement of the mount member along the axis without rotation when desired. The screw thread on one of the members may be formed from a piece or layer of a deformable material, which deforms to form a mating screw thread upon being brought into engagement with the screw thread on the other member. Also desclosed is a method of scanning a sample.

Abstract: A method and apparatus for the manufacture of synthetic vitreous silica ingots involves the production of a melt of synthetic vitreous silica in a crucible (35) within a refractory furnace (31), and the continuous withdrawal of an ingot (43) through an orifice (40) in the wall of the crucible. The silica may be deposited in the crucible by a synthesis burner (33), which may also serve to maintain the silica above its sintering temperature. The emerging ingot is supported by an arrangement of moveable clamps (44).

Abstract: Disclosed is a quartz glass product of enhanced opacity manufactured by fusion of silica particles, the opacity being enhanced by the reaction of an organosilicon additive in the course of the fusion process. A method of enhancing the opacity of a quart glass product by fusing silica particles in the presence of an organosilicon additive is also disclosed.

Abstract: A linear burner for the synthesis of silica by vapor-phase reaction of a silicon-containing feedstock in a flame comprises at least five slots opening to an exit face (52a) of the burner and extending side-by-side in the elongate direction of the linear burner, and includes means (P1-P10) to supply a separate gas flow to each of said slots. An assembly of separator plates (52) is disposed between opposed casing parts (50, 51), which assembly defines the slots. At least one of the casing parts (50, 51) defines at least part of a respective plenum chamber (54) for each gas flow, each plenum chamber (54) communicating with a different one of said slots in the separator assembly. The invention also extends to a method of operating such a linear burner.