Some results from a small high-pressure streamer chamber

In spite of the excellent results obtained for the accuracy and two-track resolution with emulsions and small bubble chambers, it is still interesting to use a streamer chamber (SC) for charm lifetime measurements because it is triggerable. A small SC with a track-sensitive volume of 50 mm diameter and 23 mm gap was constructed and operated between 5 and 20 atm pressure in the t5 test beam at the CERN Proton Synchrotron (PS). Streamer densities of 43 to 67 streamers per centimetre were found. The track width, which is determined by the diffusion of the electrons, shrinks proportionally to 1/√p and reaches a mean displacement sigma of 70 μm in space at 20 atm. Under certain kinematic conditions this allows a measurement of the charmed particle lifetime as short as 10-13 s. (orig.)