R&D for Future 100 kton Scale Liquid Argon Detectors
Large liquid argon (LAr) detectors, up to 100 kton scale, are presently being considered for proton decay searches and neutrino astrophysics as well as far detectors for the next generation of long baseline neutrino oscillation experiments, aiming at neutrino mass hierarchy determination and CP violation searches in the leptonic sector. These detectors rely on the possibility of maintaining large LAr masses stably at cryogenic conditions with low thermal losses and of achieving long drifts of
... ng long drifts of the ionization charge, so to minimize the number of readout channels per unit volume. Many R&D initiatives are being undertaken throughout the world, following somewhat different concepts for the final detector design, but with many common basic R&D issues. A LAr detector of 100 kton size, if installed underground even at moderate depth, would extend the search for proton decay via modes favored by supersymmetric grand unified models (e.g. p −→ K +ν ) up to ∼10 35 years, having from 5 to 10 times the efficiency of water Cerenkov detectors for such decays . The synergy between precise detectors for long neutrino baseline experiments, proton decay and astrophysical neutrinos (see Refs. [8, 9]) is essential for a realistic proposal of a 100 kton scale LAr detector. The LAr TPC technique, first proposed by C. Rubbia in 1977 , has been developed in the last 20 years by the ICARUS collaboration (see Fig. 1 ), culminating with a 300 ton detector (T300) successfully operated on surface  and a 600 ton detector (T600) installed undeground in LNGS along the CNGS neutrino beam, now almost ready to be commissioned. The use of LAr TPCs as neutrino detectors was pioneered already ten years ago by the ICARUS collaboration with the exposure of a 50 liters LAr TPC  on the WANF neutrino beam (see Fig. 2 ). Given the revived interest for the LAr technique, nowadays several groups have already placed  or are planning to expose  somewhat bigger LAr detectors on neutrino beams, of 170 and 130 liters active volumes, respectively. About 20k neutrino interactions are expected by spring 2010 in the ArgoNeut detector installed on the NuMI neutrino beam at FNAL in front of the MINOS Near Detector (see Fig. 3 ). Abstract We review the recent developments of new photon-detectors available for the future neutrino experiments. A photon-detector with large photo-coverage is the key component of a giant Cherenkov detector which will be an essential part of the future long baseline neutrino oscillation experiment to explore the CP violation in the neutrino sector. A photon-detector with Þne pixels is also the key component to build a Þnely segmented scintillator detectors for precision neutrino experiments. We review the large photon-detectors, Þnesegmented photon-detectors and a few novel ideas of photon-detectors. Abstract The T600 ICARUS detector has a DAQ system that has proved a quite satisfactory performance in the test run performed in Pavia in summer 2001. The electronics has been described in various papers and technical notes. In this paper, starting from the experience gained in the T600 operation, we propose an upgraded DAQ scheme that implements the same basic architecture with more performing new components and different modularity in view a multi-kton TPC (e.g. MODULAr) with a number of channels in the order of ~n * 10 5 . Also the electronics for PMTs detecting scintillation light in Ar will be shortly presented. Abstract The MINOS experiment uses the NuMI neutrino beam to make precision measurements of the neutrino mixing parameters. A beam of ν µ is produced at Fermilab. Its energy spectrum is measured near the production point, and again after 735 km at the Soudan Underground Laboratory. By looking for ν e appearance in the beam, limits can be placed on the as yet unmeasured mixing angle θ 13 . At the far detector (in the Soudan laboratory), 35 ν e candidate events are observed with a predicted background of 27±5(stat.)±2(syst.) events: a 1.5σ excess. At 90% C.L. this gives an upper limit range of sin 2 (2θ 13 ) < 0.28-0.34 for the normal neutrino mass hierarchy and sin 2 (2θ 13 ) < 0.36-0.42 for the inverted hierarchy, depending upon the CP-violating phase δ CP .