[en] A micro processor M6800 is used for the automation of scanning and premeasuring BESSY tables. The tasks achieved by the micro processor are: 1. control of spooling of the four asynchronous film winding devices and switching on and off the 4 projections lamps, 2. pre-processing of the data coming from a bi-polar coordinates measuring device, 3. bi-directional interchange of informations between the operator, the BESSY table and the DEC PDP 11/34 mini computer controling the scanning operations, 4. control of the magnification on the table by swapping the projection lenses of appropriate focal lengths and the associated light boxes (under development). In connection with point 4, study is being made for the use of BESSY tables for accurate measurements (+/-5 microns), by encoding the displacements of the projections lenses. (orig.)

[en] The stability of operation and the detection efficiency of drift chambers running in streamer mode are substantially improved when adding a few percent of organic vapour to gas mixtures composed of Ar, CO₂ and iC₄H₁₀. (orig.)

No abstract available

[en] It is shown that the properties of printed circuit delay lines, made out of thin ribbons of dielectric which are metal coated on both sides with only one side etched into a zig-zag pattern, are very similar to those consisting of double unshifted zig-zag patterns of otherwise identical geometry. The characteristics of such lines and their application to the position sensing of streamer pulses over distances of several meters are discussed. (orig.)

[en] An 18 module Cerenkov detector with a total sensitive area of 2.3m² having silica aerogel as radiator is being tested in a particle beam at CERN PS. The modules having a sensitive area of 23x55 cm² give typically a Cerenkov signal for β=1 particles of 12 photoelectrons for silica aerogel of refractive index 1.03 and a thickness of 15 cm. (Auth.)

[en] An 18 module Cherenkov detector with a total sensitive area of 2.3 m² having silica aerogel as radiatior has been tested at the CERN PS. The modules having a sensitive area of 23 x 55 cm² gave an average Cherenkov signal for β = 1 particles close to 11 photoelectrons for silica aerogel of refractive index 1.03 and a thickness of 14 cm. (orig.)

[en] In a small aerogol Cherenkov counter with diffusing walls, an increase of the photoelectron yield by 40% was measured when the voltage across the cathode to first dynode was increased from 0.6 to 1.7 kV on the 11 cm RCA 8854 photomultiplier tube. A comparison is made with results from other experiments. A general formula for diffusion-type counters is given. (Auth.)

[en] Successful operation of a drift chamber with 10 cm drift in the limited streamer mode is demonstrated. Good results were obtained with a 50-50 argon-isobutane gas mixture. A preliminary search for alternative gas mixtures avoiding the hydrocarbon quencher component is described. (orig.)

[en] The performance of an 18 module silica aerogel Cherenkov detector, with a total sensitive surface of 2.3 m², situated in the European Hybrid Spectrometer at the CERN SPS, is described. The light yield for β=1 particles is on the average 7.5+-0.3 photoelectrons. Particle identification with this detector is discussed. First results on the ageing effects of silica aerogel are presented. (orig.)

[en] This report presents the performance of drift chambers operated in the limited streamer mode with 9.4 cm maximum drift distance and position sensing along the 4.35 m long anode wire through delay line timing. Using only three timing channels a position resolution of 1 . 3 mm² is obtained over a detector surface of 19 . 435 cm². In this contribution, the emphasis is mainly put on the performance of the delay line and on the drift behaviour in streamer mode using safe gas mixtures. (orig.)