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GLACIER is a proposed giant liquid argon multi-purpose next-generation underground neutrino observatory, possibly scalable to an active mass of 100 kton, optimal for ultimate long baseline neutrino oscillation studies, nucleon decay searches and for the detection of known or unknown astrophysical neutrinos. It is one of the three detector options considered in the European FP7 design studies LAGUNA and LAGUNA-LBNO.

The long baseline neutrino oscillation experiment T2K, which uses a high intensity off-axis muon neutrino beam produced at JPARC, aims at a discovery of oscillation of muon neutrinos into electron neutrinos and measurement of the mixing angle θ13, a key parameter for further search for CP violation in the lepton sector. T2K is also designed to precisely measure the oscillation parameters Δm223 and θ23 in a disappearance oscillation mode. The major components of T2K include a neutrino beam line, muon monitors, a near detector complex ND280 located at 280 m from the proton interaction target, and the far detector Super-Kamiokande (295 km from the neutrino source), at a 2.5 degree off-axis angle from the beam. The measured neutrino spectrum at ND280 and measurements of the primary proton beam combined with the NA61 hadron production data will be used to predict the unoscillated spectrum at Super-Kamiokande. The oscillation analysis will be done by comparing the observed and predicted spectra at the far detector. The construction of the T2K neutrino beam line and the near neutrino detectors is completed. For the first data taking period with the neutrino beam, about 3 × 1019 30 GeV protons on target were accumulated. The design, performance, current status of the experiment and near future perspectives will be discussed. The results of the first physics run will be presented.

At the beginning of 2010, we presented at the J-PARC PAC an R&D program towards large (100 kton scale) liquid argon TPCs, suitable to investigate, in conjunction with the J-PARC neutrino beam, the possibility of CP violation in the neutrino sector and to search for nucleon decay. As a first step we proposed a test experiment to identify and measure charged kaons, including their decays, in liquid argon. The detector, a 250L LAr TPC, is exposed to charged kaons, in a momentum range of 540 – 800 MeV/c, in the K1.1BR beamline of the J-PARC slow extraction facility. This is especially important to estimate efficiency and background for nucleon decay searches in the charged kaon mode (p → K+, etc.), where the kaon momentum is expected to be in the few hundred MeV/c range. A prototype setup has been exposed in the K1.1BR beamline in the fall of 2010. This paper describes the capabilities of the beamline, the construction and setting up of the detector prototype, along with some preliminary results.

In this paper we present a successful experimental test of filling a volume of 6 m$^3$ with argon gas, starting from normal ambient air and reducing the impurities content down to few parts per million (ppm) oxygen equivalent. This level of contamination was directly monitored measuring the slow component of the scintillation light of the Ar gas, which is sensitive to {\it all} sources of impurities affecting directly the argon scintillation. Comment: 9 pages, 6 figures, to appear in Proc. 1st International Workshop towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba, March 2010

Designs of high-voltage (HV) systems for creating a drift electric field in liquid argon TPCs are reviewed. In ongoing experiments systems capable of approx. 100 kV are realised for a drift field of 0.5-1 kV/cm over a length of up to 1.5 m. Two of them having different approaches are presented: (1) the ICARUS-T600 detector having a system consisting of an external power supply, HV feedthroughs and resistive voltage degraders and (2) the ArDM-1t detector having a cryogenic Greinacher HV multiplier inside the liquid argon volume. For a giant scale liquid argon TPC, a system providing 2 MV may be required to attain a drift length of approx. 20 m. Feasibility of such a system is evaluated by extrapolating the existing designs. Comment: 8 pages, 13 figures, to appear in Proc. of 1st International Workshop towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba (Japan), March 2010

Tests with cosmic ray muons of a small liquid argon time projection chamber (LAr TPC) in a magnetic field of 0.55 T are described. No effect of the magnetic field on the imaging properties were observed. In view of a future large, magnetized LAr TPC, we investigated the possibility to operate a high temperature superconducting (HTS) solenoid directly in the LAr of the detector. The critical current $I_c$ of HTS cables in an external magnetic field was measured at liquid nitrogen and liquid argon temperatures and a small prototype HTS solenoid was built and tested. Comment: 5 pages, 5 figures, to appear in Proc. of 1st International Workshop towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba (Japan), March 2010

In this paper we present results from a test of a small Liquid Argon Large Electron Multiplier Time Projection Chamber (LAr LEM-TPC). This detector concept provides a 3D-tracking and calorimetric device capable of charge amplification, suited for next-generation neutrino detectors and possibly direct Dark Matter searches. During a test of a 3~lt chamber equipped with a 10$\times$10~cm$^2$ readout, cosmic muon data was recorded during three weeks of data taking. A maximum gain of 6.5 was achieved and the liquid argon was kept pure enough to ensure 20~cm drift (O(ppb)~O$_2$ equivalent). Comment: 7 pages, 6 figures, to appear in Proc. of 1st International Workshop towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba (Japan), March 2010