The ICARUS Project FRONTIERS IN CONTEMPORARY PHYSICS II. Vanderbilt University, March 5-10, Sergio Navas (ETH Zürich) " Atmospheric neutrinos

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The ICARUS Project FRONTIERS IN CONTEMPORARY PHYSICS II Vanderbilt University, March 5-10, 2001 Sergio Navas (ETH Zürich) Detection Principle The T600 Module Physics

1 The ICARUS Project FRONTIERS IN CONTEMPORARY PHYSICS II Vanderbilt University, March 5-10, 2001 Sergio Navas (ETH Zürich) Detection Principle The T600 Module Physics Programme: " Atmospheric neutrinos " Solar and Supernova neutrinos " Long Baseline neutrinos " Proton decay searches Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/2001 1

ICARUS liquid argon imaging TPC The performance of a neutrino detector is proportional to its total mass and also to its geometrical granularity with which the events can

2 ICARUS liquid argon imaging TPC The performance of a neutrino detector is proportional to its total mass and also to its geometrical granularity with which the events can be reconstructed. Wires "Bubble" size 3 x 3 x 0.2 mm3 40 cm Energy deposition measured for each point 40 cm Drift Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/2001 2

3 Neutrino and rare process physics with ICARUS Atmospheric neutrinos Supernova neutrinos ICARUS Solar neutrinos p e + +π 0 Nucleon stability Long Baseline neutrinos Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/2001 3

4 Event imaging in liquid Argon $ The LAr TPC technique is based on the fact that ionization electrons can drift over large distances (meters) in a volume of purified liquid Argon under a strong electric field. If a proper readout system is realized (i.e. a set of fine pitch wire grids) it is possible to realize a massive "electronic bubble chamber", with superb 3-D imaging. e- Ionizing track Charge Signals induced B i 0 + V Ionizing track v E v + d d d p 1st Induction wire / Screen grid 2nd Induction wire grid (x view) Collection wire grid (y view) Charge A C C Drift time Drift A B Drift time E = 500 V/cm I 0 = e(v + + v - )/d Electron-ion pairs are produced Electrons give the main contribution to the induced current due to the much larger mobility A set of wires at the end of the drift give a sampling of the track. No charge multiplication occurs near the wires electrons can be used to induce signals on subsequent wires planes with different orientations 3D imaging Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/2001 4

5 ICARUS: a graded strategy After several years of R&D and prototyping, the ICARUS collaboration is now realizing the first 600 ton module, which will be installed at Gran Sasso in the year Lab activities: We are here! Small-scale prototypes 15 ton T600 (3 tons, 50 l) ( 2x300 ton )? Cooperation with specialized industries: Air Liquide for Cryostat and Argon purification BREME Tecnica for internal detector mechanics CAEN for readout electronics Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/2001 5

ICARUS 15 ton (10m 3 ) prototype (1999-2000) A major step of the R&D program has been the construction and operation of a 10m 3 prototype T15 installation LNGS (Hall di Montaggio) % Test of the

6 ICARUS 15 ton (10m 3 ) prototype ( ) A major step of the R&D program has been the construction and operation of a 10m 3 prototype T15 installation LNGS (Hall di Montaggio) % Test of the cryostat technology & Test of the variable-geometry wire chamber ' Test of the liquid phase purification system ( Test of trigger via scintillation light ) Large scale test of final readout electronics First operation of a 15 ton LAr mass as an actual detector Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/2001 6

7 Tracks in 15 ton prototype 10m 3 Module at LNGS Wires 40 cm Wires Cosmic Ray tracks recorded during the 10 m 3 operation 76 cm Drift Drift Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/2001 7

8 Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/ The ICARUS T600 module Number of independent containers = 2 Single container Internal Dimensions: Length = 19.6 m, Width = 3.9 m, Height = 4.2 m Total (cold) Internal Volume = 534 m Sensitive LAr mass = 476 ton Number of wires chambers = 4 Readout planes / chamber = 3 at 0, ± 60 from horizontal Maximum drift = 1.5 m Operating field = 500 V / cm Maximum drift time 1 ms Wires pitch = 3 mm Total number of channels = independent aluminum containers each one transportable inside the GS Laboratory External insulation layer (400 mm) LN2 cooling circuit Signal feedthroughs HV feedthroughs Under construction 3

9 First half-module delivery in Pavia (Feb 29, 2000) Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/2001 9

10 Assembly of the T600 internal detector (Mar-Jul 2000) Cryostat Internal detector Clean workers Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

11 Wire installation in T600 internal detector (Jul-Oct 2000) Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

12 T600 - Completed Internal Detector view Wire Chamber Side A E Drift distance 1.5 m Wire Chamber Side B Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

13 Slow control sensor (behind wire planes) Wires before tensioning Purity Monitors Position meter PMT Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

14 The three wire planes at 0,±60 (wire pitch = 3mm) and one PMT Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

15 Readout electronic installation on top of dewar (Dec 2000-now) Electronic rack chimneys Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

16 Status of the T600 (first half module) Assembly of the internal detector mechanics finished. Wires positioning (3 planes) completed. Central cathode, auxiliary instrumentation, photomultipliers, sensors and signal cables installed and tested. Thermal insulation and cryogenic system proceeded in parallel. Electronics and DAQ system delivered. Planning! Next steps: ➊ Vacuum (~3 weeks) ➋ Cooling (~3 weeks) + filling ➌ LAr purification obtain big track (~20 m long)! The ICARUS T600 detector has a physics program of its own, immediately relevant for neutrino oscillation physics: solar+sn neutrinos, atmospheric neutrinos! It should be installed in LNGS tunnel next year. Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

17 Perspectives of ICARUS The ICARUS T600 detector has a physics program of its own, immediately relevant for neutrino oscillation physics: solar+sn neutrinos, atmospheric neutrinos Though with limited statistics, due its relatively small mass, compared to the standard for underground detectors set by the operating SuperKamiokande. However, the T600 should also be considered as one more step towards larger detector masses. solving technical issues associated with actual operation of a large mass LAr device in an underground site (LNGS Tunnel). fully establish the imaging, PID, calorimetric energy reconstruction capabilities of REAL events, during steady detector operations In situ proof of actual physics performance of this novel detector technique, in particular measurement of backgrounds, extrapolable to larger mass detectors Physics issues for both present and future LAr detectors: Atmospheric ν Solar+SN ν CNGS+Nufactory ν p decay Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

18 Solar neutrinos detection in ICARUS Two reactions can be measured independently: ν x Elastic scattering on atomic electron + e ν + x e ν absorption on Argon nuclei ν + 40 Ar 40 K * + e e Signature: Primary electron track Absorption: surrounded by low energy secondary tracks ( 40 K * de-excitation). Prototype setup: electron track visible down to kinetic T=150 KeV Electron track threshold = 5 MeV (needed to reduce background contribution and to establish the e - direction in elastic scattering). Sensitive to 8 B component of the solar spectrum. Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

19 Elastic scattering ν event E e = 5.6 MeV Electron track Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

20 Signal selection Elastic events : Angular distribution of the electron peaked in the solar ν direction: Absorption events : Electron track directions can be considered isotropically distributed For a 600 Ton detector All cuts imposed Events/year ε = 72% ν α Elastic channel Background e - Absorption channels Background α = 25û The off-line selection can be done in terms of the energy of the main electron and the correlation between multiplicity and energy of the associated tracks. Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

21 Absorption ν event Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

22 Solar neutrinos sensitivity R N N ES ABS / N / N ES theory ABS theory " Independent of the 8 B total ν flux predicted by solar models.. m 2 2 (ev ) ES=elastic scattering ABS=absorption events ν x ν + 40 Ar 40 K * + e e + e ν + e (a) Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/ x MSW - SMA sin 2 2θ R / R 7%( 1kt yr), 5%( 2kt yr), 4%( 4kt yr) JustSo MSW - LMA MSW - LOW

23 Supernova neutrinos expected rates ICARUS can detect neutrinos coming from stellar collapses in our Galaxy via the same two processes! Supernova neutrino rates in 5 KTON ICARUS Events/1MeV ν e Elastic Events ν e 32 <E(MeV)> 11 Expected events from a stellar collapse ocurred at 10 kpc 1.5 ν - e 13 ν µ +ν τ Process 600 ton 5 kton 1.25 ν - µ +ν- τ 9 TOTAL Elastic scattering Absorption events 0.75 Fermi ν - e GT ν µ +ν τ ν - µ +ν- τ E ν (MeV) TOTAL Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

24 T600 PHYSICS : Atmospheric neutrinos (I) The accumulated statistics will be modest. For a 2 kton x year exposure they will be comparable to first generation water Cerenkov detectors: Kamiokande, IMB 270 ν µ + ν µ CC 150 ν e + ν e CC 190 ν NC 610 events in total θ real -θ measured (degrees) All particles Only lepton Complicated final events with multi-pion products will be completely analyzed and reconstructed Zenith angle reconstruction significantly improved! Events can be fully reconstructed up to kinematics production threshold (50% of the total predicted rate has P lepton < 400 MeV) Fundamental contribution to the understanding of the low energy part of the atmospheric neutrino spectrum E ν MC (GeV) Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

25 T600 PHYSICS : Atmospheric neutrinos (II) For a 2 kton x year exposure, we will measure a significant deficit of upward-going muon-like events ν µ ν τ or ν µ ν s oscillations? The clean NC sample measured allows indirect ν τ appearance search R NC / e NC NC / νecc / ν CC Expected error on R NC/e : 15% (22%) for a 2 (1) kton x year = Uncertainty similar to the one obtained by Super-Kamiokande (we are not dominated by systematic uncertainty on poorly known cross sections, e.g. single π 0 production) data MC e data MC Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

26 Atmospheric CC events (simulated ν µ event) (simulated ν e event) 90 cm 90 cm p µ e p e 90 cm ν µ Q-el. interaction E ν = 370 MeV P µ = 250 MeV T p = 90 MeV 100 cm ν e quasielastic interaction E ν = 450 MeV P e = 200 MeV T p = 240 MeV Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

27 Proposed setup ICARUS 5kt in LNGS Hall B ICARUS T600 Two possible options: A) 8 x T600 B) 4 x T1400 (better for physics) Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

28 Atmospheric neutrinos p,he,... ν µ µ µ ν µ Earth p,he,... almost isotropic source (geomagnetic effects) π, K µ hadronic cascade + decays e Total 1535 Events/year Simulation based on FLUKA interaction and transport code, 3D representation of Earth and atmosphere, Geomagnetic effects included, All relevant physics taken into account: energy losses, polarized decays Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

29 Events (arbitrary units) Mean RMS E ((L/E) MC -(L/E) meas )/(L/E) MC Events (arbitrary units) ν µ disapearance: L/E distribution P m L 2 2 ( να νβ ) = sin θsin E Oscillation parameters: m 2 32 = 3.5 x 10-3 ev 2 sin 2 Θ 23 = 0.5 sin 2 2Θ 13 = 0.1 Mean RMS E ((L/E) MC -(L/E) meas )/(L/E) MC ( L/ E) RMS 30% Electron sample can be used as a reference for no oscillation case Events for 25 kton x year Events for 25 kton x year Electrons Log 10 (L/E) Muons 25 kt year Log 10 (L/E) Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

30 CNGS neutrino beam The expected ν e and ν τ contamination of the CNGS beam are of the order of 10 2 and 10 7 respect to the dominant ν µ. CERN INFN-AE/98-05 CERN-SL/99-034(DI) - INFN/AE-99/05 Primary protons: 400 GeV, Pots per year: 4.5x10 19 pots ν µ ν τ? ν e? Planned beam commissioning: May 2005 CERN Neutrino Beam in the Direction of Gran Sasso Distance = 732 Km CERN Gran Sasso Earth radius = 6380 Km 10.5 km below ground earth Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

31 CNGS events in 5 kton, 4 years running θ 23 = 45, θ 13 = 7 Analysis of the electron sample Exploit the small intrinsic ν e contamination of the beam (0.8% of ν µ CC) Exploit the good e/π 0 separation Statistical excess visible before cuts this is the main reason for performing this experiment at long baseline! Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

32 ν µ ν τ Background: ν τ +N τ+jet ν µ ν τ oscillations Charged current (CC) (Br 18%) ν e +N e+jet τ eνν Charged current (CC) m = ev evts 470 ν e evts Reconstructed visible energy spectrum of electron events clearly evidences excess from oscillations into tau neutrino ICARUS 4 years (after cuts) Events/20kton x year ν e + ν τ CC ν e CC ν τ CC ν e CC signal E visible (GeV) Reconstructed energy Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

33 ν µ ν e oscillations : Search for θ 13 0 m 2 32 =3.5x10 3 ev 2 sin 2 2θ 23 = 1 ICARUS 4 years 4 2 P( ν ν ) = cos θ sin 2θ 2 32 µ τ P( ν νe) = 2 2 µ sin 2θ13 sin θ Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

34 Sensitivity to θ 13 in three family-mixing (ev 2 ) m 2 23 ν µ ν e 90% allowed Sensitivity to ν µ ν e oscillations in presence of ν µ ν τ (three family mixing) 10-1 CHOOZ Factor 5 improvement on sin 2 2θ 13 at m 2 = 3x10 3 ev Almost two-orders of magnitude improvement over existing limit at high m ν µ ν τ included, Θ 23 = π/4 χ 2 min sin 2 2Θ 13 Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

Nucleon decay search 5 ktons detector 3 10 33 nucleons τ p (10

background rejection High detection efficiency Bias-free, fully

35 Nucleon decay search 5 ktons detector nucleons τ p (10 32 years) > 6 T(yr) ε 90 C.L. Thanks to excellent tracking and particle id capabilities _ p ν K + decay LAr unique tool n ν K 0 decay Extremely efficient background rejection High detection efficiency Bias-free, fully exclusive channel searches! p e + π 0 decay Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

36 p e + π 0 and p K + ν decay kinematics Exposure: 1000 kton x year _ Nuclear effects: pion absorption and rescattering included (FLUKA) 45% π 0 absorbed in Ar nucleus We see the kaon! N / 20 MeV π 0 detected π 0 absorbed N / 20 MeV π 0 detected π 0 absorbed Background free!! Total Momentum (GeV) Measured Energy (GeV) 5 kton x year τ p (p e + π 0 ) > yrs _ τ p (p K + ν ) > yrs Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

37 Conclusions The ICARUS T600, based on a novel technique, is now almost ready Given the past record with previous prototypes, we are confident that also the T600 will come into operation smoothly We hope to present the first 20 m long tracks with 3 mm granularity soon! It will demonstrate that the technique, even on such large scales, is now mature. Operation inside the Gran Sasso tunnel in the course of next year (2002) should allow an appropriate scaling up for the increase of the mass The technology, once it is scaled to the right size, will become a powerful tool in order to explore neutrino oscillations from both, accelerator and non-accelerator beams Solar and Supernova neutrinos and nucleon decay searches. Sergio Navas, ETH/Zürich, ICARUS Collaboration, 7/3/

Performance of the ICARUS T600 detector

Performance of the ICARUS T600 detector CIPANP 2003 Conference on the Intersections of Particle and Nuclear Physics New York City May 19-24, 2003 Sergio Navas University of Granada, Spain Sergio Navas