Progress Report Towards the ICANOE Detector

We present a proposal for a combined ICARUS & NOE general purpose detector, to be installed in Hall B of the Gran Sasso Laboratory.The main scientific goal is the one of elucidating in a comprehensive way the pattern of neutrino masses and mixings, following both (1) the S-KAM results and (2) the predictions on atmospheric neutrinos of the large solution of the Solar Neutrinos deficit. To achieve these goals, the experimental method is based upon the complementary and simultaneous detection of CERN beam (CNGS) and cosmic ray (CR) events. This is made possible because of the complete isotropy of the detection technique. For the currently allowed values of the S-KAM results, both CNGS and cosmic ray data will give independent measurements and provide a precise (sin²2θ; Δ m²) determination rather than a wide band of allowed values. Since we can observe and unambiguously identify νₑ,νμ and ντ components, the full (3x3) mixing matrix can be explored, reaching an ultimate sensitivity for CR neutrinos as low as Δ m² ≈ 10⁻⁵eV², well above the value observed by the Solar neutrino deficit. All separate processes, electron-CC, muon-CC and NC are equally well observed in all detail with imaging and calorimetric methods, without detector biases and down to kinematical threshold. The detector fruitfully merges the superior imaging quality of the ICARUS with the high resolution full calorimetric containment of NOE, suitably upgraded to provide also magnetic analysis of muons. It has a modular structure of independent supermodules and is expandable by the addition of such supermodules, each consisting of a low density 1.6 kton liquid target and of a high density 0.7 kton active solid target. While the basic concepts of the detector appear well established, this present conceptual design does not represent the final optimization of the complete detector. We plan to continue this process in the following months, in view of the response of scientific committees and of the possible interest of new collaborators.Our present timescale foresees the operation of a first supermodule in 2003 for atmospheric neutrino and nucleon decay physics. Additional modules will be added in the following years and a 4 supermodules 9 Kton configuration will be ready for the start of the CERN-NGS beam in 2005.