The liquid Argon TPC: a powerful detector for future neutrino experiments and proton decay searches

Abstract

We discuss the possibility of new generation neutrino and astroparticle physics experiments exploiting the liquid Argon Time Projection Chamber (LAr TPC) technique, following a graded strategy that envisions applications with increasing detector masses (from 100 ton to 100 kton). The ICARUS R&D program has already demonstrated that the technology is mature with the test of the T600 detector at surface. Since 2003 we have been working with the conceptual design of a very large LAr TPC with a mass of 50-100 kton to be built by employing a monolithic technology based on the use of industrial, large volume, cryogenic tankers developed by the petro-chemical industry. Such a detector, if realized, would be an ideal match for a Super Beam, Beta Beam or Neutrino Factory, covering a broad physics program that includes the detection of atmospheric, solar and supernova neutrinos, and searches for proton decay, in addition to the rich accelerator neutrino physics program. A "test module" with a mass of the order of 10 kton operated underground or at shallow depth would represent a necessary milestone towards the realization of the 100 kton detector, with an interesting physics program on its own. In parallel, physics is calling for a shorter scale application of the LAr TPC technique at the level of 100 ton mass, for low energy neutrino physics and for use as a near station setup in future long baseline neutrino facilities. We outline here the main physics objectives and the design of such a detector for operation in the upcoming T2K neutrino beam. We finally present the result of a series of R&D studies conducted with the aim of validating the design of the proposed detectors.

Monitoring the parameters of a large size liquid Argon Time Projection Chamber using UV laser beams

“…liquid e = 9.63 eV (5) in our experiment we have used the 4 th harmonic (λ=266 nm, corresponding to a photon energy of 4.67 eV) of a Nd-YAG laser source, the main features of which are reported in Table 2. At this wavelength at least three photons are needed to produce ionization in LAr, although the intermediate real state can make the actual multiphoton transition a 2+1 transition.…”

“…A very large LAr TPC with a mass ranging from 10 kton to 100 kton would produce an important physics output thanks to the excellent event reconstruction performance [3,4,5,6,7]. The purity of the liquid Argon is a key ingredient to achieve imaging over long drift distances (>5 m), needed for building such a large masses.…”

“…The particle momentum of an incoming particle is inferred by the measurement of its multiple scattering [2], while the detection of the local energy deposition provides particle identification. For more information, the reader is referred to [1] and references therein quoted.A very large LAr TPC with a mass ranging from 10 kton to 100 kton would produce an important physics output thanks to the excellent event reconstruction performance [3,4,5,6,7]. The purity of the liquid Argon is a key ingredient to achieve imaging over long drift distances (>5 m), needed for building such a large masses.…”

Probing late neutrino mass properties with supernova neutrinos

“…In Fig. 3, to obtain event rates, we have folded the SRN flux with the cross-section for electron neutrinos to interact with argon [16]. We have used a resonance energy of 25 MeV for the lightest neutrino mass state (taken to be 0.001 eV so that M G ≈ 225 eV).…”

Modelling electroluminescence in liquid argon

“…This technology would be especially relevant to the LAGUNA [9] proton decay and neutrino physics project, upgrades to the existing long baseline T2K experiment [10], and the proposed neutrino factory project [11].…”