ICARUS T600 Research Articles

ICARUS: perspective for sterile neutrino search at FermiLab

ICARUS T600 liquid argon TPC completed in 2013 a very successful three years run at LNGS underground laboratory exposed to CNGS neutrino and cosmic rays. The relevant physics and technical results achieved proved the full maturity of the LAr-TPC technique and the impact on the neutrino and astroparticle physics. The T600 will be exposed to Booster neutrinos in the framework of the joint ICARUS, SBND and MicroBooNE effort to definitely clarify the sterile neutrino puzzle.

Performance study of the new light collection system for the ICARUS T600 detector

The ICARUS T600 detector is the largest liquid argon time projection chamber (LArTPC) to be built and operated [1]. This detector was in operation in the INFN Gran Sasso underground laboratory until 2012, exposed to the CERN Neutrino to Gran Sasso (CNGS) νµ beam, performing neutrino oscillation studies. The ICARUS T600 is presently under refurbishment in order to make it suitable for surface level operation, as it will serve as the far detector for the Short-Baseline Neutrino (SBN) Program at Fermilab [2]. A major upgrade of the ICARUS detector in order to allow it to cope with a high cosmic background is the upgrade of the light collection system. The study presented here shows a simulation to optimize the PMT layout to allow for the localization and identification of interaction within the T600. An excellent performance can be obtained, with an error on the localization smaller than 20 cm and of the order of a few percent in the identification of cosmic rays.

TPB thickness and Quantum Efficiency measurements for the new ICARUS T600 light detection system in the SBN program.

Tetra-Phenyl-Butadiene (TPB) has been widely used in the last years in LAr experiments due to its property to convert VUV into visible light. To this purpose, a study of its property has been performed in order to obtain the best TPB coating on the PMT sensitive window for the new ICARUS T600 light detection system in the Short-Baseline Neutrino program at FNAL.

Electron diffusion measurements in the ICARUS T600 detector

In last years, the interest on LAr TPC used for neutrino physics and dark matter searches is growing; the knowledge of transport properties of Ar electrons is essential to extract faithful physical information. In particular there is a lack of experimental measurements on diffusion parameter. Dedicated runs for this measurement were carried out with the ICARUS T600 detector considering cosmic muons collected at different electric field.

Sterile neutrino searches with the ICARUS T600 detector

The successful run of ICARUS T600 at LNGS underground laboratory, receiving CNGS beam and atmospheric neutrinos, represents the first large-scale example of a liquid Argon TPC in a neutrino physics experiment. The relevant physics and technological results proved the maturity of the LAr TPC technique. The ICARUS T600 detector will take part in the SBN project at the Booster neutrino beam at FNAL, that has the goal to provide a definitive answer to the sterile neutrino puzzle by measuring both νe appearance and νμ disappearance. The detector is currently undergoing an extensive overhauling at CERN, and its installation at FNAL is scheduled for the beginning of 2017.

The ICARUS detector. Past, present and future

ICARUS T600 is currently the largest LAr TPC built as a neutrino detector. During its operation in the underground LNGS laboratory, it has recorded events from the CERN to Gran Sasso neutrino beam and cosmic rays interactions. Thanks to its excellent imaging capabilities and very good calorimetric and spatial resolutions, several meaningful results have been achieved. This paper introduces shortly the observation of a free electron lifetime exceeding 15 ms, the identification of atmospheric neutrino interactions and the search of LSND-related anomalies in the νe appearance from the νµ CNGS beam. The LSND anomaly will be further addressed by the Short Baseline Neutrino programme, carried out at the Fermilab laboratory. The ICARUS detector will be used as a far detector in this programme.

ICARUS T600: physics results and future activities

The ICARUS T600 detector has proven the effectiveness of Liquid Argon TPC technology with a successful three-year long run at the INFN Gran Sasso National Laboratories (LNGS).ICARUS T600 LNGS data strongly contributed to the global effort in searching for neutrino oscillations mediated by sterile states. A definitive clarification of the sterile neutrino puzzle will come from the new multi-station, Short Baseline Neutrino (SBN) experiment at the Booster Neutrino Beam (BNB) at Fermilab, where a refurbished T600 will act as Far Detector.Presently the T600 detector is located at CERN, undergoing a major overhauling which will allow its participation in the 5 years program of the Fermilab upcoming SBN project. Moreover, ICARUS T600 is also foreseen to collect data with the NUMI Beam to be later exploited in the wider picture of the DUNE Long-Baseline project, recently undertaken by the United States community.This contribution will report the present physics results obtained by the ICARUS Collaboration, as well as describe the overhauling activities and the physics program for the detector in its future deployment at Fermilab.

Search for space charge effects in the ICARUS T600 LAr-TPC

Space charge in Liquid Argon Time Projection Chamber is due to the accumu- lation of positive ions, produced by ionizing tracks crossing the detector, which slowly flow toward the cathode. As a consequence, electric field distortions may arise, thus hindering the possibility to produce faithful 3D images of the ionizing events. The pres- ence of space charge becomes relevant for large TPCs operating at surface or at shallow depths, where cosmic ray flux is high. These effects could interest the next phase of the ICARUS T600 detector, which will be deployed at shallow depths as a Far Detector for Short Baseline Neutrino experiment at FNAL dedicated to sterile neutrino searches. In 2001, the first ICARUS T600 module (T300) operated at surface in Pavia (Italy), record- ing cosmic ray data. In this work, a sample of cosmic muon tracks from the 2001 run was analyzed and results on space charge effects in LAr-TPCs are shown.

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

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.

ICARUS T600 - a large Liquid Argon Time Projection Chamber

The Liquid Argon Time Projection Chamber (LAr TPC) is a detection technique very well suited for the investigation of rare signals, including neutrino interactions. The ICARUS T600 is the largest LAr TPC ever built. It has recorded events both, from the CERN to Gran Sasso (CNGS) muon neutrino beam and cosmic rays interactions. Several important results have been achieved thanks to the three-dimensional event imaging and very good detector resolutions both, calorimetric and spatial. Two of them, namely the observation of a free electron lifetime exceeding 15 ms, and the search of LSND related anomalies in the νe appearance from the νμ CNGS beam will be shortly summarized.

The WA104 Experiment at CERN

The refurbishment operations, inside the WA104 programme at CERN, of the Icarus T600 detector, in view of its possible run on the FNAL short-baseline Booster neutrino beam (BNB), will be outlined.

ICARUS and Sterile Neutrinos

The ICARUS T600 detector is the largest operational liquid Argon Time Projection Chamber (LAr-TPC) ever built, and it successfully took data at the Gran Sasso laboratories (LNGS), with both the CNGS muon-neutrino beam and cosmic rays, from May 2010 to June 2013. During the data taking campaign, a dedicated search was performed for an excess of electron neutrino events, possibly related to non-standard oscillations into sterile states. No evidence of excess was found, and a new Short Baseline experiment is now being developed at Fermilab, in order to definitely prove or exclude the existence of such sterile neutrinos.

The ICARUS T600 Liquid Argon Purification System

The ICARUS detector is a liquid argon time projection chamber with unique features that make it an ideal device to be used for several particle physics applications. After years of R&D activities, the ICARUS Collaboration proposed the construction of the T600 in strict partnership with industry to guarantee the necessary and viable scaling-up of the technology from prototypal dimensions to sized plants in order to study neutrino oscillations and matter stability in an effective way. The T600 represents the largest LAr detector (760 t LAr mass) ever realized. It was installed and successfully operated for 3 years inside the underground Gran Sasso Laboratory from May 2010 to June 2013. One of the most important issues for the success of the detector technology is the liquid argon purity. Purity requirements become stronger and stronger with the increase of the detector dimensions: for a plant of the ICARUS T600 size it is necessary to keep the residual electronegative impurity content to a level of the order of 0.1 parts per billion or better all over the argon volume during the whole detector run, thus allowing the ionization tracks, created by interacting particles inside LAr, to be transported with only slight attenuation along the drift path. In this paper we present the ICARUS T600 purification plant installed at Gran Sasso Laboratory and describe in details the solutions adopted for the LAr re-circulation and purification systems that permitted to reach impressive results in terms of LAr purity thus representing a milestone for any project involving LAr and developments at higher LAr mass scale.

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

The ICARUS T600 detector, the largest liquid Argon Time Projection Chamber (LAr-TPC) realized after many years of R&D activities, was installed and successfully operated for 3 years at the INFN Gran Sasso underground Laboratory. One of the most important issues was the need of an extremely low residual electronegative impurity content in the liquid Argon, in order to transport the free electrons created by ionizing particles with very small attenuation along the drift path. The solutions adopted for the Argon recirculation and purification systems have permitted to reach impressive results in terms of Argon purity and a free electron lifetime exceeding 15 ms, corresponding to about 20 parts per trillion of O2-equivalent contamination, a milestone for any future project involving LAr-TPCs and the development of higher detector mass scales.

The trigger system of the ICARUS experiment for the CNGS beam

The ICARUS T600 detector, with its 470 tons of activemass, is the largest liquid Argon TPC ever built. Operated for three yearsin the LNGS underground laboratory, it has collected thousands of CNGSneutrino beam interactions and cosmic ray events with energy spanning fromtens of MeV to tens of GeV, with a trigger system based on scintillationlight, charge signal on TPC wires and time information (for beam relatedevents only). The performance of trigger system in terms of efficiency,background and live-time as a function of the event energy for the CNGS datataking is presented.

NEUTRINOS FROM ICARUS

Liquid Argon Time Projection Chambers are very promising detectors for neutrino and astroparticle physics due to their high granularity, good energy resolution and 3D imaging, allowing for a precise event reconstruction. ICARUS T600 is the largest liquid Argon (LAr) TPC detector ever built (~600 ton LAr mass) and is presently operating underground at the LNGS laboratory. This detector, internationally considered as the milestone towards the realization of the next generation of massive detectors (~tens of ktons) for neutrino and rare event physics, has been smoothly running since summer 2010, collecting data with the CNGS beam and with cosmics. The status of this detector will be shortly described together with the intent to adopt the LAr TPC technology at CERN as a possible solution to the sterile neutrino puzzle.

NEUTRINOS FROM ICARUS

Liquid Argon Time Projection Chambers are very promising detectors for neutrino and astroparticle physics due to their high granularity, good energy resolution and 3D imaging, allowing for a precise event reconstruction. ICARUS T600 is the largest liquid Argon (LAr) TPC detector ever built (~600 ton LAr mass) and is presently operating underground at the LNGS laboratory. This detector, internationally considered as the milestone towards the realization of the next generation of massive detectors (~tens of ktons) for neutrino and rare event physics, has been smoothly running since summer 2010, collecting data with the CNGS beam and with cosmics. The status of this detector will be shortly described together with the intent to adopt the LAr TPC technology at CERN as a possible solution to the sterile neutrino puzzle.

ICARUS-NESSiE: a sensitive search for sterile neutrinos at CERN SPS

A new experimental search for sterile neutrinos beyond the Standard Model at a new CERN-SPS neutrino beam aiming at measuring the electron and muon neutrino events with a Near and Far detectors (1600 and 330 m from the proton target) is presented. The project will exploit the ICARUS T600 LAr-TPC moved from LNGS to the CERN Far position and a new additional LAr-TPC detector, 1/4 of the T600, located in the Near position. Two magnetic spectrometers will be placed downstream of the two LAr-TPC detectors to greatly complement the physics capabilities. Comparing the two detectors, in absence of oscillations, all cross sections and experimental biases cancel out. Any difference of the event distributions at the two locations should be attributed to the possible existence of oscillations, presumably due to additional neutrinos with a mixing angle sin2(2θnew) and a mass squared difference Δm2new larger than the measured for the standard neutrinos. The superior quality of the LAr imaging TPC, in particular its unique electron-π0 discrimination allows for full rejection of backgrounds and offers a lossless νe detection capability. The determination of the muon charge with the spectrometers allows for the full separation of νμ from ν̄μ and therefore controlling systematics from muon mis-identification mainly at high momenta.

The ICARUS experiment and the neutrino velocity measurement

ICARUS T600 Liquid Argon (LAr) Time Projection Chamber (TPC) is located in the HALL B of the Gran Sasso National Laboratory, on axis with the CNGS neutrino beam. It is smoothly and continuously operating since June 2010. The experiment has proved to be well suited to address the superluminal neutrino problem firstly raised by the OPERA experiment. As A.G.Cohen and S.L.Glashow argued, Super-luminal muon neutrinos should lose their energy by producing photons and e+e− bremsstrahlung pairs, in analogy with Čerenkov radiation. The lack of observation of such a radiative process in the ICARUS T600 detector, using the CNGS beam neutrino events, immediately refuted a superluminal interpretation of the OPERA result. Moreover the ICARUS collaboration, profiting of two short periods of CNGS beam operation in bunched mode, repeatedly performed a high precision measurement of the neutrino time-of-flight (to∫) which resulted to be compatible with the time-of-flight of a particle traveling at the speed of light: the difference between the expected value based on the speed of light and the measured value is δt=to∫c−to∫ν=0.10±0.67stat±2.39syst ns.

ICARUS+NESSiE: A proposal for short baseline neutrino anomalies with innovative LAr imaging detectors coupled with large muon spectrometers

The proposal for an experimental search for sterile neutrinos beyond the Standard Model with a new CERN-SPS neutrino beam is presented. The experiment is based on two identical LAr-TPCʼs followed by magnetized spectrometers, observing the electron and muon neutrino events at 1600 and 300 m from the proton target. This project will exploit the ICARUS T600, moved from LNGS to the CERN “Far” position. An additional 1/4 of the T600 detector will be constructed and located in the “Near” position. Two spectrometers will be placed downstream of the two LAr-TPC detectors to greatly complement the physics capabilities. Comparing the two detectors, in absence of oscillations, all cross sections and experimental biases cancel out. Any difference of the event distributions at the locations of the two detectors might be attributed to the possible existence of ν-oscillations, presumably due to additional neutrinos with a mixing angle sin2(2θnew) and a larger mass difference Δmnew2. The superior quality of the LAr imaging TPC, in particular its unique electron-π0 discrimination allows full rejection of backgrounds and offers a lossless νe detection capability. The determination of the muon charge with the spectrometers allows the full separation of νμ from anti-νμ and therefore controlling systematics from muon mis-identification largely at high momenta.