Showing papers by "Antonio Ereditato published in 2004"

Design, construction and tests of the ICARUS T600 detector

Abstract: We have constructed and operated the ICARUS T600 liquid argon (LAr) time projection chamber (TPC). The ICARUS T600 detector is the largest LAr TPC ever built, with a size of about 500 tons of fully imaging mass. The design and assembly of the detector relied on industrial support and represents the applications of concepts matured in laboratory tests to the kton scale. The ICARUS T600 was commissioned for a technical run that lasted about 3 months. During this period all the detector features were extensively tested with an exposure to cosmic-rays at surface with a resulting data collection of about 30 000 events. The detector was developed as the first element of a modular design. Thanks to the concept of modularity, it will be possible to realize a detector with several ktons active mass, to act as an observatory for astroparticle and neutrino physics at the Gran Sasso Underground Laboratory and a second-generation nucleon decay experiment. In this paper a description of the ICARUS T600 is given, detailing its design specifications, assembly procedures and acceptance tests. Commissioning procedures and results of the technical run are also reported, as well as results from the off-line event reconstruction.

Study of electron recombination in liquid argon with the ICARUS TPC

Abstract: Electron recombination in liquid argon (LAr) is studied by means of charged particle tracks collected in various ICARUS liquid argon TPC prototypes. The dependence of the recombination on the particle stopping power has been fitted with a Birks functional dependence. The simulation of the process of electron recombination in Monte Carlo calculations is discussed. A quantitative comparison with previously published data is carried out.

Analysis of the liquid argon purity in the ICARUS T600 TPC

Abstract: The results reported in this paper are based on the analysis of the data recorded with the first half-module of the ICARUS T600 liquid argon Time Projection Chamber (LAr TPC), during a technical run that took place on surface in Pavia (Italy). We include results from the linearity, uniformity and calibration of the electronics, measurements on the electron drift velocity in LAr at different electric fields, as well as the LAr purity achievement of the detector. Two complementary techniques were used to measure the drift electron lifetime inside the active volume: the first, from the data of a purity monitor, gives a measurement localized in space; the second, based on the study of the signals produced by long minimum ionizing tracks crossing the detector, provides a LAr volume averaged value. Both methods yield consistent results over the whole data taking period and are compatible with an uniform LAr purity over the whole volume. The maximal drift electron lifetime value was recorded before the run stop and was about 1.8 ms. From an interpretation of the observed drift electron lifetime as a function of time, we conclude that the adopted technology would allow for drift distances exceeding 3 m.

Supernova relic neutrinos in liquid argon detectors

Abstract: We study the possibility of detecting the background of supernova relic neutrinos (SRN) with liquid argon time projection chamber (TPC) detectors. As far as this study is concerned, these experimental devices are mainly sensitive to electron neutrino signals, and could provide further information on both the supernova explosion mechanism and the star formation rate at redshifts . We study in detail the main contributions to background in the relevant energy range from 8B and hep solar neutrinos as well as from low energy atmospheric neutrino fluxes. Depending on the theoretical prediction for the SRN flux we find that for a 3 kton and a 100 kton liquid argon TPC detector the signal may be observed at the 1σ and 4σ level, respectively, with five years of data taking.

WARP liquid argon detector for dark matter survey

Abstract: The WARP programme is a graded programme intended to search for cold Dark Matter in the form of WIMP's. These particles may produce via weak interactions nuclear recoils in the energy range 10-100 keV. A cryogenic noble liquid like argon, already used in the realization of very large detector, permits the simultaneous detection of both ionisation and scintillation induced by an interaction, suggesting the possibility of discriminating between nuclear recoils and electrons mediated events. A 2.3 litres two-phase argon detector prototype has been used to perform several tests on the proposed technique. Next step is the construction of a 100 litres sensitive volume device with potential sensitivity a factor 100 better than presently existing experiments.

Supernova Relic Neutrinos in Liquid Argon detectors

Abstract: We study the possibility of detecting the background of Supernova Relic Neutrinos (SRN) with liquid Argon Time Projection Chamber (TPC) detectors. As far as this study is concerned, these experimental devices are mainly sensitive to electron neutrino signals, and could provide further information on both Supernova explosion mechanism and on star formation rate at redshifts z <2. We study in details the main contributions to background in the relevant energy range from 8B and hep solar neutrinos as well as from low energy atmospheric neutrino fluxes. Depending on the theoretical prediction for the SRN flux we find that for a 3 kton and a 100 kton liquid Argon TPC detectors the signal may be observed at the 1 sigma and 4 sigma level, respectively, with 5 years of data taking.

WARP: a WIMP double phase Argon detector

Abstract: The WARP programme for dark matter search with a double phase argon detector is presented. In such a detector both excitation and ionization produced by an impinging particle are evaluated by the contemporary measurement of primary scintillation and secondary (proportional) light signal, this latter being produced by extracting and accelerating ionization electrons in the gas phase. The proposed technique, verified on a 2.3 liters prototype, could be used to efficiently discriminate nuclear recoils, induced by WIMP's interactions, and measure their energy spectrum. An overview of the 2.3 liters results and of the proposed 100 liters detector is shown.

Ideas for future liquid Argon detectors

Abstract: We outline a strategy for future experiments on neutrino and astroparticle physics based on the use, at different detector mass scales (100 ton and 100 kton), of the liquid Argon Time Projection Chamber (LAr TPC) technique. The LAr TPC technology has great potentials for both cases with large degree of interplay between the two applications and a strong synergy. The ICARUS R&D programme has demonstrated that the technology is mature and that one can built a large ($\sim$ 1 kton) LAr TPC. We believe that one can conceive and design a very large mass LAr TPC with a mass of 100 kton by employing a monolithic technology based on the use of industrial, large volume cryogenic tankers developed by the petro-chemical industry. We show a potential implementation of a large LAr TPC detector. Such a detector would be an ideal match for a Superbeam, Betabeam or Neutrino Factory, covering a broad physics program that could include the detection of atmospheric, solar and supernova neutrinos, and search for proton decays, in addition to the rich accelerator neutrino physics program. In parallel, physics is calling for another 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 present here the main physics objectives and outline the conceptual design of such a detector.