The characteristics of the cylindrical drift chambers of the detector CELLO: Investigation with muons from high altitude cosmic rays

The characteristics of the cylindrical drift chambers of the CELLO detector were investigated using muons from cosmic radiation. An iterative procedure for the parameterization of the time-distance relation is presented. The numerical approximation obtained with this procedure agrees to within 50 micron with the experimental nonlinear relation. The chamber characteristics are determined with and without magnetic field (B = 1.32 T). A long detection probability plateau is obtained with an argon/ethane 50%/50% gas mixture. An average spatial resolution of 170 microns is obtained without B. It is found that the drift chambers react when the electrons from the first 2 to 3 primary ionizations reach the signal wire. The average response probability is 97.5%; the over response probability is 3.6%. The average spatial resolution with B is 170 microns; the response probability is 98.3%.