1

F. VaraniniFor the ICARUS Collaboration

ICARUS and the future of Liquid Argon technology

The ICARUS Collaboration

M. Antonelloa, P. Aprilia, B. Baibussinovb, M. Baldo Ceolinb,, P. Benettic, E. Calligarichc, N. Cancia, S. Centrob, A. Cesanaf, K. Cieslikg, D. B. Clineh, A.G. Coccod, A. Dabrowskag, D. Dequalb, A. Dermenevi, R. Dolfinic, C. Farneseb, A. Favab, A. Ferrarij, G. Fiorillod,

D. GibinP, A. Gigli Berzolaric,, S. Gninenkoi, A. Guglielmib, M. Haranczykg, J. Holeczekl, A. Ivashkini, J. Kisiell, I. Kochanekl, J. Lagodam, S. Manial, G. Mannocchin, A. Menegollic,

G. Mengb, C. Montanaric, S. Otwinowskih, L. Perialen, A. Piazzolic, P. Picchin, F. Pietropaolob, P. Plonskio, A. Rappoldic, G.L. Rasellic, M. Rossellac, C. Rubbiaa,j, P. Salaf, A. Scaramellif, E. Segretoa, F. Sergiampietrip, D. Stefana, J. Stepaniakm, R. Sulejm,a, M. Szarskag, M. Terranif, F. Varaninib, S. VenturaP, C. Vignolia, H. Wangh, X. Yangh,

A. Zalewskag, K. Zarembao.

a Laboratori Nazionali del Gran Sasso dell'INFN, Assergi (AQ), Italyb Dipartimento di Fisica e INFN, Università di Padova, Via Marzolo 8, I-35131 Padova, Italyc Dipartimento di Fisica Nucleare e Teorica e INFN, Università di Pavia, Via Bassi 6, I-27100 Pavia, Italyd Dipartimento di Scienze Fisiche, INFN e Università Federico II, Napoli, Italye Dipartimento di Fisica, Università di L'Aquila, via Vetoio Località Coppito, I-67100 L'Aquila, Italyf INFN, Sezione di Milano e Politecnico, Via Celoria 16, I-20133 Milano, Italyg Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Science, Krakow, Polandh Department of Physics and Astronomy, University of California, Los Angeles, USAi INR RAS, prospekt 60-letiya Oktyabrya 7a, Moscow 117312, Russiaj CERN, CH-1211 Geneve 23, Switzerlandk Institute of Theoretical Physics, Wroclaw University, Wroclaw, Polandl Institute of Physics, University of Silesia, 4 Uniwersytecka st., 40-007 Katowice, Polandm National Centre for Nuclear Research, A. Soltana 7, 05-400 Otwock/Swierk, Polandn Laboratori Nazionali di Frascati (INFN), Via Fermi 40, I-00044 Frascati, Italyo Institute of Radioelectronics, Warsaw University of Technology, Nowowiejska, 00665 Warsaw, Polandp INFN, Sezione di Pisa. Largo B. Pontecorvo, 3, I-56127 Pisa, Italy

An “electronic bubble chamber”3

40 bar pressure

Pulsed ≈ 1ms

40 bar pressure

Pulsed ≈ 1ms

no over-pressureContinuously

sensitive

no over-pressureContinuously

sensitiveBubble diameter ≈ 3 mm(diffraction limited)

“Bubble” size 3 x 3 x 0.3 mm3

Medium: heavy freon

Sensitive mass 3.0 tonDensity 1.5 g/cm3

Radiation length 11.0 cmCollision length 49.5 cm

Medium: Liquid argon

Sensitive mass Many ktonDensity 1.4 g/cm3

Radiation length 14.0 cmCollision length 54 cm

ICARUS-T600 at LNGS● CNGS (CERN ν to

GranSasso beam) νµ NC and CC

interactions νµ => ντ , τ->e

νµ => νe θ13

νµ => νe ”LSND” ν velocity

•Atmospheric ν•Proton decay

•Major milestone for future LAr detectors

• Run with CNGS beam just finished (2010-12)

4

30 m3 LN2 Vessels

N2 liquefiers: 12 units, 48 kW total cryo-power

N2 Phase separatorThe ICARUS-T600 detector

Two identical modules (740 t LAr mass) Liquid Ar active mass ≈ 476 t 1.5 m drift length, Vdrift=1.55mm/µs

4 TPC wire chambers (2 chambers per module)

3 readout wire planes/chamber, wires @ 0,±60°

≈ 54000 wires, 3 mm pitch, 3 mm plane spacing

74 PMT for scintillation light: VUV sensitive ( TPB wave-shifter).

5

54000 elec.channels

Gas purification

Liquid purification

Liquid argon purityDetection principle

Non-destructive read-out is guaranteed by grid transparency condition:

E1/Edrift = E2/E1 > (1+ρ)/(1-ρ)

ρ = 2πr/p (r=wire radius)

Liquid argon purity

Electronegative impurities in LAr attenuate the electron signal as exp(−tD/τe)

CRITICAL ISSUE FOR SIGNAL QUALITY

τele ~ 300 μs / ppb (O2 equivalent). Main contaminants are O2, H2O, CO2.

Liquid Ar recirculation/purification by chemical filters (Oxysorb/Hydrosorb). Reduces initial impurities (after filling)

Recirculation/purification of gas Ar blocks impurities created by microleaks/diffusion from warm parts of detector

Purity is continuously monitored by observing attenuation in cosmic muon tracks (m.i.p.)

Gas recirculation

Liquid recirculation

Result of more than 20 years of R&D!!!

LAr purity in ICARUS-T600

● τ>5 ms (~60 ppt [O2]eq) during all data taking

● Electron attenuation is 17% on maximum drift distance 1.5 m

● Promising towards future larger TPCs (t=21 ms measured in small test-facility TPC) Jinst5, 03005(2010)

● System is highly redundant, stable despite pump failures

ICARUS T600 Light detection system● LAr is good scintillator: ~ 2.5 107 γ/GeV

@λ~128 nm

● 4% of γ within ~1 ns from ionization process can provide absolute time reference (t0). “Slow” component (~1 µs) used for triggering

● 74 PMTs (54+20) located behind the wire chambers. PMTs developed for LAr temperature and coated with wavelength-shifter (TPB). Signal is ~50-100 phe/GeV/D2[m]

● Sums of PMT signals in a chamber are used for triggering and determination of t0

● Threshold of ~ 100 phe: trigger is efficient down to few hundred MeV

9

Module 2-Left chamber

2.40 ms offset value in agreement with 2.44 ms ν tof (40 µs fiber transit time from external lab to Hall B)

Spill duration reproduced (10.5µs), 1 mHz event rate , ≈ 80 events/day

CNGS: CNGS “Early Warning” signal sent 80 ms before the SPS p extraction:

allows to open a 60 ms wide gate around neutrino arrival time at LNGS. PMT sum signal for each chamber in coincidence with the beam gate.

Cosmic Rays: PMT sum signal: coincidence of two adjacent chambers (50% cathode

transparency) Globally 36 mHz trigger rate achieved: ~130 cosmic events/h

Charge-based local trigger (SuperDaedalus SD): on-line hit-finding/zero-skipping algorithm implemented in FPGA’s, used

to improve trigger efficiency at low energy (below 500 MeV)

ICARUS T600 trigger system

[JInst 5:P12006(2010)]

∑

∑

=

=

−=

−=

128

0128

8

08

)(128

1)(

)(8

1)(

i

i

itQtQ

itQtQ

S(t)=Q8(t)−Q128(t)

● Wire signal is filtered by a DOUBLE REBINNING algorithm (high-frequency and low-frequency noise removed)

● “Peak” signal generated if filtered signal above threshold

● Trigger based on majority of “peak” signal over 16 wires

● Algorithm tested on a small TPC (50l) at INFN-LNL

● Trigger on cosmic ray electrons/photons, deposition on few wires

● Filter proved capable to trigger on events of few MeV

Super-Daedalus trigger

Edep(MeV)

SuperDaedalus trigger

•All channels in all views equipped since summer 2012

•Since March 2012, an additional trigger based on charge deposition on Collection wires is active in CNGS trigger

•Requiring 5 cm track length, SD trigger provides additional rate <50mHz

SuperDaedalus in ICARUS-T600

Slide: 12

Low energy e.m. interaction

Combined triggers

Super Daedalus triggers

PMT triggers

• Data analysis on-going: promising improvement of cosmic trigger efficiency in 50÷500 MeV energy range (relevant for atmospheric ν and proton decay search)

SuperDaedalus in ICARUS-T600

192 MeV58 MeV

ICARUS T600 timeline

● 2010: Successful assembly and commissioning of ICARUS-T600

● 2011 -> Dec 3rd, 2012 T600 data-taking with CNGS beam and cosmic rays

● Dec.2012-June 2013: Data-taking with cosmic rays ● 2013: Decommissioning● 2014: ?? (see later)

January-March: vacuum phase (10-5 mbar)April-May: cooling with LN2 and fillingMay 28th : first CNGS neutrinoJune-September: commissioning of DAQ/trigger October: start of physics runs

Slide: 13

Nov. 2011 & March 2012: two run periods with bunched beam for v velocity measurement

Nov. 2011-Feb. 2012: upgrade of PMT DAQ and timing

CNGS neutrino runs – summary

• ICARUS T600 fully operational since Oct. 1st 2010

2010: Oct. 1st ÷ Nov. 22nd

5.8 1018 pot

2011: Mar. 19th ÷ Nov. 14th

4.44 1019 pot

2012: March 23rd ÷ Dec. 3rd Detector live-time > 93% in

2011 and 2012 November 2011 and May 2012:

timing measurement with bunched beam.

END CNGS data taking: December 3rd, 2012

3.5 1019 pot

Slide: 14

2012: Mar. 23th ÷ Dec. 3rd

● Tracking devicePrecise 3D topology and ionization

measurement

● Measurement of energy deposition (dE/dx):e /γ remarkable separation

(0.02 X0 samples)Particle identification by dE/dx vs range

● Total energy reconstruction of the events from charge integrationFull sampling, homogeneous calorimeter with

excellent accuracy for contained events

RESOLUTIONSLow energy electrons: σ(E)/E = 11%/√E(MeV)+2%Electromagn. showers: σ(E)/E = 3%/√E(GeV)Hadron showers: σ(E)/E ≈ 30%/√E(GeV)

Points : Data dE/dx vs residual rangecompared to Bethe-Bloch curves

LAr TPC performance

Points : Data dE/dx vs residual rangecompared to Bethe-Bloch curves

Points : Data dE/dx vs residual rangecompared to Bethe-Bloch curves

Michel electrons from µ decay

Induction2

Collection

Induction1

Muon track reconstructed from Coll and Ind2 views,seen in Ind1 projection

NEW: Single 3D PLA-fit optimized to all 2D hits + identified 3D reference points. 2D hit-to-hit associations not longer needed -> missing parts in a view and horizontal tracks are now accepted.

3D reconstruction example on data

Slide: 16

Important step forward for T600 and for future LAr detectors

real data dE/dx compared to Bethe-Bloch curves in a bin of residual range (8-12 cm):

Neural network algorithm applied to dE/dx vs. residual range relation:dE/dx from calorimetry (quenching included)dx from 3D reconstruction

Particle ID

Slide: 17

dE/dx mean value in narrow range bins (1cm) vs MC

kaons – unlikely, less than 0.3% may be misidentified as stopping particles

Proton sample includes particles interacting at very low energy protons

muons & pions

Calibration with stopping particles: examplesSlide: 18

PId: proton

PId: not-stopping

PId: pion

Color bands: MCBlue : protons Red : kaonsGreen: pions Violet: muonsDots : hits from real tracks

• Deposited dE/dx vs residual range • Black dots: not consistent with any pattern, most probably protons interacting at very low energy with emission of neutrons and photons

MC: µ=2.37 MeV/cm; rms=1.37Data: μ=2.32 MeV/cm; rms=1.31

Calibration from CNGS muons Measurement of dE/dx

Slide: 19

Example of stopping muon track (single event):

•Landau-Gauss fit Most Probable value – agrees with expectations within 2%•Gauss σ parameter ~ 10% of mean – reflects MIP hit charge signal/noise ≈ 10

pµ =2.2GeV/c

Global distribution for hundreds of real/MC muon tracks in CNGS νµCC

Possible thanks to developments to 3D reco (δ rays and showers rejected)

Very good agreement (~ 2-3%) – residual small difference due to noise patterns and their effects on δ ray.

Calibration from CNGS muons Muon momentum by multiple scattering

Slide: 20

● Key tool to measure momentum of non-contained µs: essential for νμCC event reconstruction.

● “Segments” of muon track (length Lseg) used in order to enhance MS contribution w.r.t. apparent deflection due to measurement errors θMS ~ √Lseg/p θmeas ~ L seg

-3/2

● Distribution of deflection angles θ between successive segments is considered

● Two independent algorithms: CLASSICAL METHOD fits RMS of θ as a function of Lseg

KALMAN METHOD fixes optimized Lseg

and fits dependency of θRMS from assumed track momentum p0

p (MeV)

Θ2RMS/Θ2

exp.

PKALMAN =7.5 GeV

Pclass. = 6.8 GeV

Lseg(mm)

Θ2RMS.

Slide: 21

classical

kalman● Check with

STOPPING MUONS from CNGS νs:(0-4 GeV) both methods in good agreement with calorimetry

● MUONS from νµCC of CNGS neutrinos: classical method in good agreement with MC

Muon momentum measurements

data

MC

Muon momentum measurements

Mean=0.99RMS=0.23

Mean=1.03RMS=0.12

Slide: 22

Example of data: kaon decay in a CNGS event

p

Kπ

μ

• Kaon track• Muon track

Residual range (cm)

dE/d

x(M

eV/c

m) Corresponding

PId patterns

Collection_view

cathode

Right chamber. collection view

Left chamber. Induction 2 view

CNGS beamPrimary vertexkaon

π0 reconstruction23

θ

Ek16b = 685 ± 25 MeV

Ek16a = 102 ± 10 MeV

Collection

Mπo = 127 ± 19 MeV/c²

θ = 28.0 ± 2.5º

pπo = 912 ± 26 MeV/c

π0 showers identified by: • 2γ conversion separated from primary vertex• Reconstruction of γγ invariant mass• Ionization in the first segment of showers

From CNGS Real DatadE/dx of the initial part of low E showersdE/dx from a single long stopping muon (p=1.8GeV/c),Most Probable dE/dx in agreement with expect. Signal/noise from Landau+ gaussian ≈10

CNGS CC events reconstructionSlide: 24

close-up of two e.m. showersCollection

Induction2

Conversion distances6.9 cm, 2.3 cm

Primary vertex: very long μ (1), e.m. Cascade (2), p (3).Secondary vertex:Longest track (5) is μ coming from stopping k (6), μ decay observed.

M* = 125±15 MeV/c2

12.5 m

1.5

m

2.2 mip’s(average)

π0

Track1 (µ)2 3 (π)Sec. vtx.45 (µ)6 (K)7 8

Edep[MeV]27025215147977731487362834.5 GeV

cosx0.0690.054-0.001

0.009

0.0000.414-0.613

cosy-0.040-0.4200.137

-0.649

-0.2390.7930.150

cosz-0.997-0.906-0.991

0.761

-0.971-0.446-0.776

pµ 11 GeV(multiple scattering)

ICARUS T600 physics program

● CNGS events: 2800 CC + 900 NC events collected Muons from upstream GS rock ≈ 12000 ev (≈ 8200 on TPC front face) Intrinsic beam νe CC ≈ 26 ev νµ -> ντ detecting τ decay with kinematical criteria (~2 event τ->e ) νµ -> νe ( θ13 ) from e-like CC events excess at E < 20 GeV (~5 events CC) Search for sterile neutrinos in LSND parameter space, studying e-like CC

events at E > 10 GeV

● “Self triggered” events (still being collected): ≈ 100 ev/year of atmospheric ν CC interactions. Proton decay with 3x1032 nucleons , zero bckg. in some of the channels

● ICARUS contributed to the superluminal neutrino problem raised by OPERA: Search for the analogue to Cherenkov radiation by high energy CNGS

neutrinos at superluminal speeds: Physics Letters B 711 (3-4): 270–275 Precision Measurement of the neutrino time-of-flight with the 2011 (Physics

Letters B 713 (1): 17–22) and 2012 (arXiv:1208.2629) CNGS νµ bunched beams

25

ICARUS physics publications

● On the ‘’neutrino velocity’’ 1- M. Antonello et al.,”A search for analogue to Cherenkov radiation by high energy

neutrinos at superluminal speeds in ICARUS”, Phys.Lett. B711 (2012),17

2- M. Antonello et al., “Measurement of the neutrino velocity with the

ICARUS detector at CNGS beam”, Phys Lett. B713 (2012), 17

3- M. Antonello et al., “Precision measurement of the neutrino velocity with

ICARUS detector in the CNGS beam”, JHEP 11(2012)049

δt = tc-tν = 0.10±0.67±2.39 ns -> δvν = (vν – c) < 1.2 10-6 c @ 90% CL

● On the “LSND anomaly” 4- M. Antonello et al., “Experimental search for the LSND anomaly with the ICARUS LAr-

TPC detector in the CNGS beam”, ArXiv:1209.0122 (submitted to Physics Letters)

5.- C. Rubbia, “Presentation to NOW2012”

6.- P. Sala, “Presentation to the SIF Conference”

And many others...

Slide# : 26

“Sterile” neutrinos ?● First hypothesized in a seminal paper by Bruno Pontecorvo in 1957, as particles

not interacting via any of fundamental interactions of SM except gravity. If heavy enough, they may also contribute to cold or warm dark matter.

● Sterile νs may mix with ordinary neutrinos via a mass term. Evidence of oscillations in the 10-2-1 eV2 range may be building up by several “anomalies” :

Combined evidence for some possible anomaly: 3.8 + 3.8 + 2.7 + 3.0+ 2.0 σ!

LSND anomaly: observation of νe in νµ beams at accelerators

Disappearance of anti-νe in several reactor experiments

Disappearance of νe in very intense (Mega-Curie) ν sources

Cosmological measurements may hint to more than 3 neutrino species

-

Search for LSND-like effect in ICARUS● CNGS beam is peaked in the 10-30 GeV range: LSND oscillations can be studied

by looking for νe appearance in the νµ beam(intrinsic νe ~ 1%).● νe signature observed visually (efficiency ~74%, estimated from MC). ● Present sample: 1091 neutrino events from 2010 and 2011.

● There are differences with respect to LSND experiment:L/Eν ~ 1 m/MeV at LSND, but L/Eν≈36.5 m/MeV at CNGSA LSND -like short distance oscillation signal averages to

sin2(1.27∆m2new L /E) ~1/2 and <P>(νµ→νε)~ ½ sin2(2θnew)

● Expected background for νe appearance:

3 events due to the intrinsic νe beam contamination

1.3 events due to θ13 oscillations:

0.7 events of νµ ->ντ oscillations with electron production.● The total is ~4 expected events (taking efficiency into account)

28

νe CNGS events 29

● Two CC events have been observed in data sample, with a clearly identified electron signature:

(a) total energy = 11.5 ± 1.8 GeV, Pt = 1.8 ± 0.4 GeV/c (b) Total visible energy = 17 GeV. Pt = 1.3 ±0.18 GeV/c

● In both events the single electron shower in the transverse plane is clearly opposite to the remainder of the event 

From a single electron to a shower

● Measured dE/dx along each individual wire of the electron shower (event B of previous slide)

● Region (≥ 4.5cm from primary vertex) where the track is well separated from other tracks and heavily ionising nuclear prongs.

● The evolution of dE/dx from single ionising electron to shower is shown and compared to the expected dE/dx distribution for single and double minimum ionising tracks

30

Results31

● The ICARUS experiment is presently compatible with the absence of a LSND anomaly. The limits are respectively 3.41 (90% CL) and 7.13 events (99% CL)

● the limits to the oscillation probability are: P(νμ ν→ e) ≤ 5.4 x 10-3 (90% CL)

P(νμ ν→ e) ≤ 1.1 x 10-2 (99% CL)● At small ∆m2 ICARUS strongly

enhances the probability with respect to the short baseline experiments.

● LSND/MiniBooNE signal are strongly constrained by ICARUS: a small region around ∆m2 ≈ 0.5 eV2 , sin2(2θ) ≈ 0.005 survives

Neutrino velocity: indirect test (2011)● OPERA experiment published time-of-flight measurement of CNGS neutrinos:

“faster than light” by a “superluminal excess” δ= = (v2–c2)/c2=5 10-5 ● Cohen and Glashow [Phys. Rev. Lett., 107 (2011) 181803] : superluminal νs should

lose energy mainly via e+e- bremstrahlung

(on average 0.78•Eν energy loss/emission)

Γ: Emission rateδ = (v2–c2)/c2

32

FULL SIMULATION IN ICARUS:● total ν event suppression for Eν > 30 GeV

● ~107 e+e- pairs /1019 pot/kt

---> isolated e.m. shower (Edep > 200 MeV) within 150 mrad from CNGS beam axis with no hadronic activity RESULTS:

● No candidate EM-shower found in ~400 ev.● CC and NC spectra agree with expectations● Limit on δ < 2.5 10−8 90% CL

dEdx

= 5112

GF2

192π 3 ν6

E3δ Γ = 2

35GF

2

192π 3 ν5

E3δ

CC

Neutrino velocity: indirect test

Neutrino time of flight33

Neutrino time of flight

● Special “bunched” beam mode: very short batches (1.8 ns

● Corrections for vertex position in TPC and for PMT delays

● First measurement in nov. 2011, higher-precision run in May 2012

● 4 independent timing systems (added GPS intercalibration, ICARUS trigger timestamp, optic fiber calibration)

● ICARUS PMT-DAQ improved (channel synchronization at10 ps, all PMT signals recorded)

● Improved geodetic measurement of TPC positions

● 1.8 1017 pot; 25 neutrino/rock muon events (consistent with expectations)

~1.99 m(~ 6.67 ns)

1.14 m(~4.6 ns) Closest

PMT’

ICARUS upstream wall

Neutrino velocity: direct TOF measurement34

● Results consistent with 0 (v at speed of light)● All timing systems agree with each other. Combined estimate:

δt = tofc – tofν = 0.18 ± 0.69stat ± 2.17syst ns δ(v/c) = (v-c)/c = 0.7± 2.8stat ± 8.9syst 10-7

Neutrino velocity: direct TOF measurement

ICARUS-NESSiE at the CERN-SPS

• The clarification of the sterile neutrino “mystery” requires observation at different distances. In this way, the values of ∆m2

new and of sin2 2θnew can be separately identified.

PROPOSAL AT CERN-SPS (P-347) introduces important new features:

L/E matches to the ∆m2 window for the expected anomalies. “Imaging” detector capable to identify unambiguously all reaction

channels with a “Gargamelle class” LAr-TPC Great e/π0 separation capability: electrons identified with 90%

efficiency and 0.1% π0 contamination

Near and far detectors, in order to reduce beam systematics Magnetic spectrometer to measure muon charge and p (NESSIE) Interchangeable ν and anti-ν focussed beams Very high rates due to large masses, in order to record relevant effects

at the percent level (>106 νµ,≈104 νe)

Both initial νe and νµ components cleanly identified.

SEE TALK BY S. DUSINI!Slide 35

Future LAr-TPCs: the ”Modular” approach

● Liquid Argon TPCs can be a very promising detector tecnhology for uture CP violation studies; future projects will have to have masses of several ktons

● The most naïve design would assume a single (~100 kton) LAr container of a huge size.

● Increasing the size of a single container does not introduce significant physics arguments in its favour: most events under study (low-energy beams, cosmic neutrinos, proton decays) are of much smaller dimensions.

● In case of even tiny accidental leaks (ppb), the whole volume of LAr will be totally contaminated. Spare container vessels for ≈100 kton are unrealistic.

● A modular structure with several separate vessels, each of a few thousand tons, seems a more realistic solution.

● It would also allow to repeat the engineering design of the unit, progressively reducing cost and construction times.

● It would permit more flexibility in experiment schedule, allowing for gradual expanding of a detector.

● A reasonable single volume unit could be of 8 x 8 m2 cross section, a drift gap of 4 m and a length of about 60 m, corresponding to 3840 m3 of liquid or 5370 t of LAr.

36

Slide# : 37

The MODULAr detector

● Each chamber is a scaled-up version of ICARUS (x 2.663):8 X 8 m2 LAr cross section and about 60 m length Two gaps within a same cryogenic volume: 10’740 ton4 m drift (2.66 ms), Edrift = 0.5 kV/cm, H.V.: -200 kV 3-D imaging like ICARUS, 6 mm pitch (~50000 chs)PMTs will extract the trigger and give time reference to LAr signal.

5 kt 5 kt

From ICARUS to Modular

● The continuous operation of ICARUS detector for 3 years has proved that LAr-TPC detector tecnhology is mature.

● It also demonstrated that underground operation of a large volume of ultra-pure LAr could be done in stable and safe conditions for a long time.

● The new detector will keep most components that have been developed with industry for ICARUS.

● Technically, its extension of a gap to the 5 kt scale is entirely straightforward and smoothly realized without major changes, depending on the physics goals.

● At the available rate of 500 t/d, namely 1/8 of the present LAr European production, each 21.5 kt unit can be filled in about two months.

● Negative ions inside the detector drift extremely slowly (≈ 1 mm/s at 500 V/cm) and may produce space charge distortions proportional to ≈ Ldrift

2 .Field stabilization may be required beyond a critical drift volume.● A very efficient mixing of the LAr is crucial to ensure a very uniform free electron

yield, purity and drift speed. ● For safety reasons, a shallow-depth (~1200 m water eq.) arrangement with multiple

accesses appears as highly preferable to a very deep underground hall.

38

Modular potential for CP violation 39

● Preliminary studies show that a LAr-TPC of ~50 kt could be used for investigating CP violation through νµ-> νe measurements

● An optimal baseline for such study would be a large ~800km, in a low-energy range (0.25 to 3 GeV)

● This arrangement will allow to minimize background from τ's and matter effects

● This idea could be realized in a new shallow-depth hall at LNGS .

Energy range CP-conservation δCP = 90° δCP = -90° E < 3 GeV 1459.7 1088.1 1715.3

E < 1.5 GeV 343.2 261.1 495.6 E < 0.8 GeV 32.5 14.4 52.9 E < 0.45 GeV 8.7 4.7 19.9

Expected events for 5 years/50 kt:

Slide 40

Conclusions

● ICARUS-T600 run with CNGS beam has just finished successfully

● It proved LAr-TPC is a mature technology for large experiments

● Important physics results (neutrino velocity, LSND effect) published, others are on the way

● Lots of experience gained in cryogenics, triggering, analysis ● In the near future, ICARUS-T600@SPS may give an important contribution to study of sterile neutrinos

● Good prespective for future CP-violation studies; scaling up to modular detectors of several kton possible with limited R&D

● ModuLAr project may be “revived” and adapted to new physics knowledge and detector experience

LNGS_May2011 Slide 41

Thank you !

41

LNGS_May2011 Slide 42

Backup slides

42

Coils

B

NESSiE: Far and Near Magnetic Iron Spectrometers

FAR

detector

layers

● Exploit expertise acquired in design, construction/operation of OPERA

● RPC detector with digital read-out● Same design scheme for electronics

1800 + 700 m2 of RPC20,000+12,000 digital channelsPrecision Trackers

Mu

on c

har

ge m

isid

enti

fic a

tion

Air magnets

iron magnet: one (two) arms

●Two-fold dipole magnets:- Air-magnet downstream ICARUS

for low momentum µ ID- a massive long Iron-magnet to

provide extensive p measurement

Charge misidentification percentage event selection, eff./reconstr. included

Slide 44

ICARUS-NESSiE sensitivity

e-appearance: 1 year νμ beam (left)2 year antiνμ beam (right)for 4.5 1019 pot/year,3% syst. uncertainty on ν energy spectrum.

νμνe νμνe

e/µ-disappearance: 1 year ν

μ beam (left)

1 year νμ + 2 years

anti-νμ beams (right)

νμνμ νeνe

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

LSND allowed region isfully explored in both cases