The ICARUS project: a 3000 t LAr TPC for neutrino physics and a search for nucleon decays

The ICARUS collaboration has developed in an intensive R&D program the novel liquid argon Time Projection Chamber (LAr TPC) technique. The final detector is planned to contain 3000 t of LAr, divided into five 600 t (T600) modules, and will be operated at the Gran Sasso underground laboratory in Italy. The physics program of the collaboration is to study neutrino oscillations with the long base line neutrino beam from CERN to the Gran Sasso laboratory (CNGS), atmospheric, solar and supernova neutrinos, and a sensitive search for nucleon decays. The technique was first developed with several small scale prototype detectors and resulted in a full scale T600 detector consisting of two identical 300 t half-modules. The maximal drift length of the electrons in LAr is 1.5 m requiring a contamination of the LAr with electronegative impurities < 0.1 ppb (O 2 equivalent). The first 300 t half-module was taken in operation in the year 2001 at Pavia (Italy) and tested in a three months run taking cosmic ray data. Results of this test run are presented, demonstrating the excellent calorimetric and imaging properties of the detector.