Abstract: On the basis of a known process for the production of a preform for an optical fiber for optical data transmission technology, the productivity of the process for the production of complex refractive index profiles is to be improved by providing a quartz glass substrate tube which exhibits different doping in radial direction, introducing a core glass made of synthetic quartz glass into the substrate tube and covering the substrate tube with a jacket tube. A substrate tube suitable therefor is also being provided which tube requires less core glass material for the production of the preform, whether during the internal deposition or for the core glass rod in the rod-in-tube technique.

Abstract: On the basis of a known process for the production of a preform for an optical fiber for optical data transmission technology, the productivity of the process for the production of complex refractive index profiles is to be improved by providing a quartz glass substrate tube which exhibits different doping in radial direction, introducing a core glass made of synthetic quartz glass into the substrate tube and covering the substrate tube with a jacket tube. A substrate tube suitable therefor is also being provided which tube requires less core glass material for the production of the preform, whether during the internal deposition or for the core glass rod in the rod-in-tube technique.

Abstract: In a known process for the manufacture of an elongated porous SiO2 preform, SiO2 particles are deposited on the mantle surface of a cylindrical carrier rotating about its longitudinal axis. The SiO2 particles are formed by means of a plurality of deposition burners which are arranged, at a distance from one another, in at least one burner row extending parallel to the longitudinal axis of the carrier. The burners are moved in a repeated cycle back and forth along the forming preform and between turnaround points where the direction of their motion is reversed. Measures are taken in the process to prevent or reduce overheating of the preform in the turnaround point regions. These measures can lead to variations in the rate of deposition.

Abstract: In a known process for the production of quartz glass bodies, SiO.sub.2 particles are deposited of the mantle surface of a cylindrical carrier rotating about its longitudinal axis, forming an elongated, porous preform, where the SiO.sub.2 particles are formed in a plurality of flame hydrolysis burners which are arranged in at least one burner row parallel to the longitudinal axis of the carrier and are moved at a preset translational speed forward and back between turnaround points at which points their direction of movement is reversed, and in which process the preform is sintered. In order to make available on this basis an easily accomplished process that makes it possible to manufacture a preform which is largely free of localized density variations, the invention proposes on the one hand that the base value of the surface temperature of the preform being formed be kept in a range between 1,050.degree. C. and 1,350.degree. C.

Abstract: To produce a free-flowing granulate which has a high bulk density and a defined particle size distribution, which generates little dust, is easy to handle, and is suitable as a starting material for quartz glass products, the mixing operation includes a first mixing phase, in which the materials to be mixed are subjected to a slow mixing action to form a coarse-grained mass, and a second mixing phase, in which the coarse-grained mass is converted to a fine-grained mass by a more intensive mixing action which grinds and compacts the grains. The content of silica powder in the materials to be mixed is adjusted at least during the second mixing phase to a value of at least 75 wt. %.

Abstract: Starting from a process for producing a rod-like preform, in particular for optical fibers, in which a tubular blank whose refractive index changes, viewed in the radial direction is fed to a heating zone, is softened there, and in the softened state is shaped to give the preform, a method is described for producing preforms which are hyperpure and low in defects, in which the blank used is one whose refractive index decreases, viewed in the radial direction, from the outside inwards, starting from at least one interface which is at a sufficient distance from the outer surface of the blank, of which that part which has been softened in the heating zone is introverted apart from an outer skin, and by which the preform is formed in the longitudinal axis of the tubular blank, counter to the direction in which the latter is fed to the heating zone, and in which the remaining outer skin is drawn off as a rod in the feed direction of the blank.

Abstract: Electrochemical luminescent cell having a spacing of the plates (1, 2) provided with electrodes (5 and 6, respectively) from 10 to 100 .mu.m, in which at least one of the oppositely located electrodes has a grid structure (13) or surface roughness, the size and mutual hole distance and maximum surface roughness of which, respectively, lie in the order of magnitude of the spacing (3) of the electrode plates.

Abstract: A detection apparatus of a simple construction is formed from an electro-chemiluminescence cell (12) having connections for the supply and the discharge of a liquid to be examined, particularly a mobile phase coming from the separation column of a liquid chromatograph, a voltage source (11) and a detector (14) for electric current, which are connected to the electrodes (1, 2) of the cell (12). Preferably a radiation-sensitive element (13) is also provided.

Abstract: Electrochemical luminescent cell with a getter material.