ICARUS: experience from an existing large scale LAr TPC

ICFA 2014 Paris 8-10 January 2013

D. Gibin Dipartimento di Fisica e Astronomia and INFN Padova For the ICARUS Collaboration

The ICARUS Collaboration

M. Antonelloa, B. Baibussinovb, P. Benettic, F. Boffellic, A. Bubakk, E. Calligarichc, S. Centrob, A. Cesanaf, K. Cieslikg, D. B. Clineh, A.G. Coccod, A. Dabrowskag,

A. Dermenevi, R. Dolfinic, A. Falconec, C. Farneseb, A. Favab, A. Ferrarij, G. Fiorillod, D. Gibinb, S. Gninenkoi, A. Guglielmib, M. Haranczykg, J. Holeczekl, M. Kirsanovi,

J. Kisiell, I. Kochanekl, J. Lagodam, S. Manial, A. Menegollic, G. Mengb, C. Montanaric, S. Otwinowskih, P. Picchin, F. Pietropaolob, P. Plonskio, A. Rappoldic, G.L. Rasellic,

M. Rossellac, C. Rubbiaa,j,q, P. Salaf, A. Scaramellif, E. Segretoa, F. Sergiampietrip, D. Stefana, R. Sulejm,a, M. Szarskag, M. Terranif, M. Tortic, F. Varaninib, S. Venturab,

C. Vignolia, H. Wangh, X. Yangh, A. Zalewskag, A. Zanic, K. Zarembao.

a Laboratori Nazionali del Gran Sasso dell'INFN, Assergi (AQ), Italy b Dipartimento di Fisica e Astronomia e INFN, Università di Padova, Via Marzolo 8, I-35131 Padova,

Italy c Dipartimento di Fisica Nucleare e Teorica e INFN, Università di Pavia, Via Bassi 6, I-27100 Pavia, Italy d Dipartimento di Scienze Fisiche, INFN e Università Federico II, Napoli, Italy e Dipartimento di Fisica, Università di L'Aquila, via Vetoio Località Coppito, I-67100 L'Aquila, Italy f INFN, Sezione di Milano e Politecnico, Via Celoria 16, I-20133 Milano, Italy g Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Science, Krakow, Poland h Department of Physics and Astronomy, University of California, Los Angeles, USA i INR RAS, prospekt 60-letiya Oktyabrya 7a, Moscow 117312, Russia j CERN, CH-1211 Geneve 23, Switzerland k Institute of Theoretical Physics, Wroclaw University, Wroclaw, Poland l Institute of Physics, University of Silesia, 4 Uniwersytecka st., 40-007 Katowice, Poland m National Centre for Nuclear Research,, 05-400 Otwock/Swierk, Poland n Laboratori Nazionali di Frascati (INFN), Via Fermi 40, I-00044 Frascati, Italy o Institute of Radioelectronics, Warsaw University of Technology, Nowowiejska, 00665 Warsaw, Poland p INFN, Sezione di Pisa. Largo B. Pontecorvo, 3, I-56127 Pisa, Italy q GSSI, Gran Sasso Science Institute, L’Aquila, Italy

The ICARUS single-phase T600 LAr-TPC at LNGS laboratory

Slide: 3

Two identical modules 3.6x3.9x19.6 ≈ 275 m3 each Liquid Ar active mass: ≈476 t Drift length = 1.5 m (1 ms) HV = -75 kV; E = 0.5 kV/cm v-drift = 1.55 mm/μs Sampling time 0.4μs (sub-mm

resolution in drift direction)

4 wire chambers: 2 chambers per module 3 “non-distructive” readout wire planes per chamber wires at 0,±60° (up to 9 m long)

Charge measurement on collection plane ≈ 54000 wires, 3 mm pitch and plane spacing

20+54 8” PMTs for scintillation light detection: VUV sensitive (128nm) withTPB wave shifter

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LN2 vessels

readout electronics

T300 T300

cryogenics (behind)

cathode

readout wire arrays

E E

1.5m

The ICARUS T600 detector at LNGS Laboratory

4

2012

2011

2010

T600 decommissioning @ LNGS is successfully proceeding from June 27th

cryostats empty on July 25th (740 out of 760 tons LAr recovered); detector @ room temperature on September 1st.

TPC chambers, cryogenic plant, read-out electronics, chimneys,... and ancillary systems will be recovered.

ICFA 2014

Exposed to CNGS beam up to Dec. 3rd 2012: a 8.6 1019 pot event statistics has been collected with a remarkable detector live-time > 93 %.

In parallel data taking with Cosmics has been conducted to study detector capability for atmospheric , p-decay search (0.73 kty exposure).

LAr purity

West Cryostat East Cryostat

60

ppt

[O

2] e

q

max

dri

ft

New pump

Recirculation LAr pump faults New Barber Nichols pump successfully

tested (Apr – June 2013) allowing to exceed tele > 7ms

tele > 5ms (~60 ppt [O2] eq): maximum charge attenuation of 17% at 1.5m

tele ≈21 ms (≈15 ppt [O2] eq.), achieved on a 120 liters ICARINO prototype.

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A multi-faceted programme

Our future physics oriented programme is characterized by:

1) Continued analysis of the ≈3000 events already collected with CNGS2. A main result has been the major clarification of the sterile neutrino search, now concentrated on a small possible window in Dm2

41,, and compatible with the cosmological prediction for dark matter. More results are also coming.

2) Overhaul of T600 and construction of a smaller T150 detector “clone” under the CERN approved WA104 experiment in view of a short baseline dual detector experiment.

3) This new dual detector configuration installed either at CERN or at FNAL short -baseline beam will definitively clarify the sterile neutrino questions. It will also ensure the bulk of preparatory phase of the LNBE collaboration, accumulating > 106 events for test and analysis purposes as a running premise to LBNE.

4) Possible long term utilization of T600 as “near detector” of LBNE.

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T600 run at LNGS: first publications

1. “Underground operation of the ICARUS T600 LAr-TPC: first results”, JINST 6 (2011) P07011.

2. “A search for the analogue to Cherenkov radiation by high energy neutrinos at superluminal speeds in ICARUS”, PLB 711 (2012) 270.

3. “Measurement of neutrino velocity with the ICARUS detector at the CNGS beam”, PLB 713 (2012) 17.

4. “Precision measurement of the neutrino velocity with the ICARUS detector in the CNGS beam”, JHEP 11 (2012) 049.

5. “Precise 3D Reconstruction Algorithm for the ICARUS T600 Liquid Argon Time Projection Chamber Detector”, AHEP 2013 (2013) 260820.

6. “Experimental search for the LSND anomaly with the ICARUS detector in the CNGS neutrino beam”, EPJ C73 (2013) 2345.

7. “Search for anomalies in e appearance from m beam”, EPJ C73 (2013) 2599.

Analysis of the large amount of physics data becoming progressively the main activity of the CNGS2 collaboration

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A search for LSND effects with ICARUS at CNGS

There are differences w.r.t. LNSD exp.

- L/E ~1 m/MeV at LSND, but

L/E ≈36.5 m/MeV at CNGS

- LSND -like short distance oscill. signal

averages to sin2(1.27Dm2new L /E) ~1/2

and <P>m→e ~ 1/2 sin2(2qnew)

When compared to other long baseline results (MINOS and T2K) ICARUS operates in a L/E region in which contributions from oscillations are not yet too relevant.

Unique detection properties of LAr-TPC technique allow to identify unambiguously individual e-events with high efficiency.

The CNGS facility delivered an almost pure m beam in 10-30 GeV E range (beam associated e ~1%) at a distance L=732 km from target.

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Selection of e events

The “Electron signature” requires: A charged track from primary vertex, m.i.p. on 8 wires, subsequently

building up into a shower; very dense sampling: every 0.02 X0 Isolation (150 mrad) from other ionizing tracks near the vertex in at

least one of the TPC views.

Electron efficiency studied with events from a MC (FLUKA) reproducing in every detail the signals from wire planes: h = 0.74 ± 0.05 (h’ = 0.65 ± 0.06 for intrinsic e beam due to its harder spectrum).

e CC event candidates are visually selected with vertex inside fiducial volume (for shower id.) : > 5 cm from TPC walls and 50 cm downstream

Energy selection: <30 GeV

50% reduction on intrinsic beam e

only 15% signal events rejected

m CC events identified by L > 250 cm primary track without had. int.

e MC event

Search for e events in CNGS beam

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The new ICARUS results

Experimental pictures of one of the four events with a clear electron signature found in the sample of 1995 interactions (6.0 1019 pot over the full recorded statistics of 8.6 1019 pot).

In all events the single electron shower is opposite to hadronic component in the transverse plane.

The evolution of the actual dE/dx from a single track to an e.m. shower for the electron shower is shown along the individual wires.

The expected number of e- events from intrinsic νe beam, q13~90 and m-t oscillations is then 6.4±0.9 (syst. only).

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1 m.i.p.

2 m.i.p.

1 m.i.p.

2 m.i.p.

θ

Ek = 685 ± 25 MeV

Ek = 102 ± 10 MeV

Collection

mπo = 127 ± 19 MeV/c² θ = 28.0 ± 2.5º

pπo = 912 ± 26 MeV/c

• MC: single electrons (Compton) • MC: e+ e– pairs (g conversions) • data: EM cascades (from p0 decays)

MC

p0 reconstruction:

e/g separation and p0 reconstruction in ICARUS

Mgg: 133.8±4.4(stat)±4(syst) MeV/c2

Unique feature of LAr to distinguish e from g and reconstruct p0

Estimated bkg. from p0 in NC and μ CC : negligible (from MC and scanning)

Sub-GeV E range

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Exclusion of the low energy MiniBooNE experiment

The ICARUS results exclude the existence of the (otherwise questionable) low energy sterile neutrino peak presented by MiniBooNE both in the neutrino and antineutrino channels. This is also confirmed by OPERA.

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EP

J C

. 73

(2013)

2599

● the present ICARUS limit ● the limits of KARMEN ● the positive signals of LSND and MiniBooNE

limit of KARMEN

allowed MiniBooNE

allowed LSND 90% allowed LSND 99%

ICARUS results: E.PJ C 73 (2013) 2599

present ICARUS

exclusion area

ICARUS result strongly limits the window of parameters for a possible LSND anomaly to a very narrow region (Dm2 ≈ 0.5 eV2 and sin22q ≈ 0.005) where there is an overall agreement (90% CL) of

LSND-like exclusion from the ICARUS experiment

13 ICFA 2014 However the original LSND anomaly requires the direct verification with anti-s

A new coherence of the global 3+1 fits

Global fits of sin2qme (appearance) & sin2qee and sin2qmm (disappearance) with corresponding Dm2

41: a well defined common region 0.82<Dm241<2.19 eV2 well

within expectations of relevant cosmological measurements. The crucial indication in favor of short-baseline is still the old LSND result.

MiniBooNE experiment has been inconclusive: hence new and better

experiments are needed to check the presence of these signals.

The conditionally approved CERN WA104 experiment will give a definitive answer to the sterile neutrino hypothesis, if the required and anti- beams will be available

Giunti, Laveder et al.,arXiv:1308.5288

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ICARUS contribution is relevant in excluding most of the area.

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Question & Comments on Machado talk

●In the above plot, the ICARUS limit is placed at sin2(2θ)~ 4 10-2 (99% CL)

while the published ICARUS result is sin2(2θ)=1.5 10-2 (99% CL) EPJ C73 (2013) 2599: ●Apparently the ICARUS sensitivity has been calculated independently by

Machado et al obtaining a result different from that published by the ICARUS collaboration.

●In addition most likely only the first ICARUS result (EPJ C73 (2013) 2345) has considered disregarding the more recent update.

●The OPERA result does not seem to be included as well.

●WARNING: the red allowed appearance region is conflicting with the experimental ICARUS/OPERA limits

3D reconstruction (example of stopping µ)

Simultaneous 3D polygonal fit 2D hit-to-hit associations no longer needed

Adv.High Energy Phys.

2013 (2013)260820

T300 real event

Induction 2 view

Collection view

Induction 1 view

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Automation of reconstruction

CNGS event primary vertex: automatic reconstruction

Validation with visually identified CNGS vertices

algorithm efficiency ~ 97%

automatic event segmentation algorithm

Track identification

Shower identification

Ready in 2D, to be extended in 3D

FIRST STAGE, output from segmentation: clusters and vertices Candidates for shower: high density of vertices

Just single hits-> neutron, noise

Deltas are excluded during the clusters merging .

Selected example in green

SECOND STAGE, Track clusters, after merging clusters from the segmentation stage:

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Measurement of muon momentum via multiple scattering

In the T600 and in future LAr TPCs, a method to measure the momentum of escaping μ is needed in order to reconstruct μ CC events

Deflections due to Multiple Coulomb Scattering (MS) provide such a tool

Horizontal m stopping in the T600 are an excellent benchmark

Calorimetric measurement is possible

The energy range (0.5-4 GeV) perfectly matches future short and long baseline experiments

A sample of 1002 stopping muons from CNGS interactions in the upstream rock has been selected and analyzed

Muon momentum reconstructed by calorimetric measurement for the stopping muon sample

23

0

6.13

lX

l

p

MeV noiseRMS

q

The RMS of q depends on p and on the meas. error

Slide: 19 ICFA 2014

Distribution of momentum by MS pMS vs momentum by calorimetry pcal MS measured over lm=4 m, and requiring a residual m length of 1 m

Work in progress

Slide: 20

Muon p determination by MS is possible with a resolution ≈ 15% in the momentum range of interest for future LAr TPCs

Calorimetric momentum estimate <1%

3 d reco

Event by event ratio pMS / pcal

Bremsstrahlung

3D reconstructed track with nodes

Filling with estimated dE/dx

Muon “cluster’ used for MS

Identified rays

<PMS/PCal)>= 0.97

(PMS/PCal) = 0.16

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rays and brem photons excluded for MS determination

The need for a continuing neutrino programme

The recent, major success of ICARUS-CNGS2 experiment has conclusively

demonstrated that LAr-TPC is the leading technology for future short/long baseline accelerator driven neutrino physics.

INFN has just concluded an important cooperation agreement toward a joint

experiment with US-LBNE collaboration, involving the long term realization of a

truly large mass, LAr-TPC detector for a search of CP violation in the lepton

sector, proton decay and other topics.

We strongly believe that the exclusive utilization of charged particle beams will

be vastly insufficient/unrealistic, at least at the level of development &

complexity of our LAr-TPC programme, and to prepare adequately for the long

term realization of the LBNE.

The direct and continued access to a neutrino beam either at CERN or alternatively to FNAL is necessary to maintain the appropriate levels in R&D and participation in physics developments within a “learning” process based on real events and cross sections.

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Next neutrino activities

ICARUS will be moved to CERN early 2014 for overhauling and complemented with a new smaller T150 module “clone” of 1/4 of T600 (WA104).

A MOU between CERN and the participating institutions (INFN) is under preparation, with the installation of the ICARUS detectors in the “Gargamelle Hall” of the West Area. The duration of this program is of about two years.

ICARUS will then be operated either at CERN, if a beam will be made available on a reasonable time schedule, or else at FNAL, provided it will be approved, collecting a large event sample (≥106) at short baseline with appropriate energy for the future LBNE experiment.

In addition to a definitive clarification of sterile neutrino, the R&D programme in LAr may pave the way to ultimate realization of the LNBE detector f.i. with:

An accurate determination of cross sections in Argon;

The experimental study of all individual CC and NC channels;

The realization of sophisticated algorithms for the most effective identification of the events.

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Experimental clarification of anomalies

A proposal for a dual baseline experiment has been initially presented at CERN as early as 2009, followed by a number of documents to the SPSC.

Our proposed experiment, collecting a large amount of data both with neutrino and antineutrino focusing, should be able to give a likely definitive answer to the 4 following queries:

the LSND+MiniBooNe both antineutrino and neutrino m e

oscillation anomalies;

The Gallex + Reactor oscillatory disappearance of the initial -e signal, both for neutrino and antineutrinos

an oscillatory disappearance maybe present in the m signal so far unknown

Accurate comparison between neutrino and antineutrino related oscillatory anomalies, maybe due to CPT violation.

In absence of these “anomalies”, the signals of the detectors should be a precise copy of each other for all experimental signatures and without any

need of Monte Carlo comparisons. The beam at CERN represents by far the best alternative for such searches.

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Alternative 1: ICARUS at CERN

Near position: 460 m 150t LAr-TPC detector to be build + magnetic spectrometer

Far position: 1600 m ICARUS-T600 detector + magnetic spectrometer

New CERN SPS 2 GeV neutrino facility in North Area

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Exploring all channels: expected sensitivity

e-appearance: 1 year μ beam (left) 2 year anti-μ beam (right) for 4.5 1019 pot/year, 3% syst. uncertainty μe μe

e/m-disappearance: 1 year μ beam (left) 1 year μ + 2 years anti-μ beams (right)

ee

combined “anomalies”: from reactor s, Gallex and Sage experiments.

LSND allowed region is fully explored in both polarities

In addition: Detector R&D (T150) Neutrino cross sections (huge statistics of e) Event reconstruction “pave the way for future LBL experiments”

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Alternative 2. LAr-TPC alternative at Fermilab

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Proposal has been submitted to move the ICARUS LAr-TPC T600 to FNAL. The optimal location is common to the short baseline neutrino beam, about 700 m from the Booster Beam (BNB), and to the off-axis neutrino flux from the NuMI beam line.

Proposal to FNAL:arXiv:1312.7252

expected sensitivity @ FNAL

e-appearance: 3 year μ beam (left) 5 year antiμ beam (right) for 2.2 1020 pot/year, 4% syst. uncertainty

μe

e-disappearance: 3 year μ beam Shown also the combined “anomalies”: from reactor s, Gallex and Sage experiments.

ee

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charge identification with Magnetic Field essential to reduce the large e contamination in negative polarity

μe

R&D LAr Programme

Vigorous technology developments while maintaining the already achieved basic

features of T600 will introduce important new features (details in C. Montanari talk) :

Magnetizing LAr

LAr Purification

New thermal insulation

New cold bodies design

Compensating recombination effects

Modification on T600 and new electronics for T150

New light collection system

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• Though intended as the near detector for the sterile neutrino search, the T150 is the ideal tool to implement new solutions, especially for introduction of a magnetic field, purification schemes and cryogenics.

• New electronic read-out under development:

Same architecture as for T600 but implementing up-to-date components and new ideas for the layout.

New T150 LAr-TPC

• Present T600 design extended to T150 module (1/4 T600): 2 wire chambers, 3 read-out planes each, field shaping electrodes and cathode, separating 2 drift volumes (1.5 m drift).

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LAr Magnetization

The introduction of an appropriate magnetic field to the LAr-TPC permits to further contribute to the progress of LAr technology, allowing the unambiguous determination of the sign and momentum of the secondary charged particles and a greatly improved visibility of the e.m. showers.

It provides an even closer visual similarity to the one of a “Gargamelle like” bubble chamber, with the added advantage of an accurate calorimetry and dE/dx identification of the tracks.

Slide# : 30 ICFA 2014

Example of a 4 GeV e-neutrino event,

with a negative electron, p0 , p+ and proton in the final state

Conclusions

The recent, major success of ICARUS-CNGS2 experiment has conclusively demonstrated that LAr-TPC is a leading technology for future short/long baseline accelerator driven neutrino physics.

Both T600 and T150 LAr-TPC detectors will become operational with the vigorous CERN support (approved experiment WA104) in about two years and ready for a short baseline experiment either ad CERN or at FNAL.

On a longer time scale, INFN has concluded an important cooperation agreement towards a joint experiment with US-LBNE collaboration, in view of the realization of a large mass LAr-TPC detector.

The direct/continued access to a neutrino beam either at CERN or FNAL is necessary to maintain the appropriate levels in R&D/participation in physics developments within a “learning” process based on real events.

ICARUS is the only operational, physics production scale LAr detector and it shall be so for several years to come. We intend to:

contribute to definitely clarify sterile neutrino existence (CERN/FNAL)

collaborate with LBNE during the preparation phase and with a large amount of neutrino events at the appropriate energy

Use T600 as a convenient “near detector” in LBNE.

Slide# : 31 ICFA 2014

ICFA 2014 LNGS_May2011 Slide 32

Thank you !

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