Measurement of the optical properties of the components of an aerogel threshold Cherenkov detector with wave-length-shifter-lightguide readout

For the experimental set-up SAPHIR a new large area Cherenkov-counter for the separation of Pions and Kaons (in the range of 1.0...3.5 GeV/c) is planned. This paper describes first investigations for the construction of an Aerogel-Cherenkov-counter with Wavelengthshifter-Lightguide read-out which is adapted to the conditions of SAPHIR. For testing this principle of read-out a testdetector has been built and first measurements were taken at the Bonn 2.5 GeV-synchrotron. The average detected light-output is 0.5 photons per event with (β=1)-particles. The enhancement of the light-output via wavelength-shifter doped aerogel was tested but not experimentally confirmed. Every component of this detector can be improved - the efficiencies of these improvements are compiled and the enhancement of the light-output is provided to 1.5...2 detected photons per (β=1)-particle. (orig.)