  The INFN and the ICARUS collaboration originally developed the technology of
the LAr-TPC. Located the underground LNGS Hall-B, the ICARUS T600 detector has
been performed over three years with remarkable detection efficiency featuring
a smooth operation, high live time, and high reliability. About 3000 CNGS
neutrino events have been collected and are being actively analyzed. ICARUS
will now be moved to CERN for an extensive R&D program. The T600 detector will
be overhauled and complemented with a similar T150 detector. These improvements
are performed in collaboration with the LBNE experiment, of which several INFN
Institutions are now members. As a novelty, a SC magnetic field of about 1 T
will be introduced. During 2016 it is proposed to move the experiment to FNAL
where short base line neutrino beams are available, complementing the approved
MicroBooNe experiment which will start operation in 2014. The ICARUS detectors
at FNAL will be an important addition since, in absence of anomalies, the
signals of several detectors at different distances from the target should be a
copy of each other for all experimental signatures. Due to the reduced mass, in
MicroBooNE the anti-neutrino signal is too weak for a sensitive comparison.
Hence, a definitive clarification of the LSND anomaly requires the exploration
of the anti-neutrino signal provided by the much larger T600. The magnetic
field will allow separating the anti-neutrino signal from the neutrino-induced
background. It is proposed to expose the T600 at the Booster NuBeam at ~700 m
from target; the T150 will be located at ~150 m. The T600 will also receive
>10^4 nu_e events/year from the off-axis NUMI beam peaked around 1 GeV and
exploitable to prepare for the LBNE experiment. The ICARUS teams are also
interested in extending the participation to other short baseline neutrino
activities collaborating with existing FNAL groups.
