ArgoNeuT and MicroBooNE: LAr-TPC’s at Fermilab.

Liquid Argon Time Projection Chamber technology provides unique features in event imaging and calorimetric resolution. These characteristics, combined with a good rejection power and a (virtually) unlimited active mass, make this detector one of the best candidate for the next generation of long-baseline neutrino oscillation experiments aimed at precision measurements of the MNPS matrix elements. Up to now the largest LAr-TPC operated is the first semi-module of the ICARUS T600 detector (300 tons of LAr). The scalability of this technology to massive detectors (>=5 ktons) is still to be proven. The ArgoNeuT detector, a small LAr-TPC (0.24 ton of active mass) exposed to the NuMI beam at FNAL currently producing the first low-energy neutrino events in a LAr-TPC, is the first step of a staged US program to realize and operate a massive LAr-TPC detector. The proposed MicroBooNE experiment, a LAr-TPC of 100 tons of active mass, to be exposed to the Booster Neutrino Beam and the NuMI beam at FNAL, is the next crucial step of this program. Design details and experimental goals of both experiments are reported in this paper. [ABSTRACT FROM AUTHOR]