Operation and performance of the ICARUS T600 cryogenic plant at Gran Sasso underground Laboratory

Abstract

A: ICARUS T600 liquid argon time projection chamber is the first large mass electronic detector of a new generation able to combine the imaging capabilities of the old bubble chambers with an excellent calorimetric energy measurement. After the three months demonstration run on surface in Pavia during 2001, the T600 cryogenic plant was significantly revised, in terms of reliability and safety, in view of its long term operation in an underground environment. The T600 detector was activated in Hall B of the INFN Gran Sasso Laboratory during spring 2010, where it was operated without interruption for about three years, taking data exposed to the CERN to Gran Sasso long baseline neutrino beam (CNGS) and cosmic rays. In this paper the T600 cryogenic plant is described in detail together with the commissioning procedures that lead to the successful operation of the detector shortly after the end of the filling with liquid argon. Overall plant performance and stability during the underground run are discussed. Finally, the decommissioning procedures, carried out about six months after the end of the CNGS neutrino beam operation, are reported. K: Time projection Chambers (TPC); Noble liquid detectors (scintillation, ionization, double-phase); Large detector systems for particle and astroparticle physics; Cryogenic detectors A X P : 1504.015562015 JINST 10 P12004

The Short-Baseline Neutrino Program at Fermilab

“…(59). The detector has been operated for 3 years (2011-2013) in the Gran Sasso Laboratory in Italy, where it demonstrated the underground operation of a large high-purity LAr detctor (60,61,62), measured the neutrino velocity (63,64,65), and searched for evidence of neutrino oscillations (37) using the CERN Neutrino to Gran Sasso (CNGS) neutrino beam. The detector is divided into two identical, adjacent cryostat modules (T300), as can be seen in Fig.…”

Experimental observation of an extremely high electron lifetime with the ICARUS-T600 LAr-TPC

“…To keep the electronegative impurities in LAr at a very low concentration level, each module is equipped with two gasseous Argon (GAr) and one LAr recirculation/purification systems [3,7,9]. Argon gas is continuously drawn from the cryostat ceiling and, re-condensed, drops into Oxysorb T M filters and finally returns to the LAr containers.…”

“…In April 2013 a major upgrade of the LAr recirculation system was performed in the East cryostat [7,8,9]. The ACD CRYO pump used during the first 2 years of run was replaced with a new Barber Nichols BNCP-32C-000 with an external motor similar to the ones used in the LN2 circuit, which worked in a very efficient and reliable way without frequent stopping.…”

The ICARUS Experiment

“…The LAr purity measurements during the Gran Sasso run show that an electron lifetime exceeding 7 ms (corresponding to <50 ppt of O 2 equivalent contaminants and to 12% maximum charge attenuation at the longest drift distance) has been obtained for the majority of the ICARUS data taking. In 2013, improvements in the recirculation system allowed an unprecedented 16-ms lifetime corresponding to 20 ppt O 2 equivalent LAr contamination [4,5], to be obtained demonstrating the effectiveness of single-phase LAr-TPC technique and paving the way toward the construction of huge LAr-TPC detectors with even longer drift distances (up to 5 m of drift).…”