PERFORMANCE OF A 3-TON LIQUID ARGON TIME PROJECTION CHAMBER

We have constructed and operated a 3 ton liquid argon time projection chamber as part of the R&D programme for the ICARUS project. We report on the analysis of events from cosmic rays and from radioactive sources collected from June 1991 to June 1993. We have systematically investigated the performance and the physical parameters of the detector. We present here the results obtained from the analysis of the cosmic rays data on the following items: the electron drift velocity, the electron lifetime, the free electron yield, the electron diffusion coefficient, the spare resolution and the particle identification capability. The data from radioactive sources are used to study the energy resolution in the MeV range. The in depth understanding of the basic physics aspects of the liquid argon TPC allows us to conclude that such a detector can be built in large sizes and reliably operated over long periods of the time, providing a new instrument for physics experiments.