ICARUS and the status of LAr technology Carlo Rubbia LNGS-Assergi, - - PowerPoint PPT Presentation

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ICARUS and the status of LAr technology

Carlo Rubbia LNGS-Assergi, Italy CERN, Geneva, Switzerland

Charm production in a neutrino interaction The total visible energy is 3.58 GeV.

History: a Gargamelle neutrino event

Japan_Dec 2010 Slide# : 3 Japan_Dec 2010 Slide# : 3

The path to massive liquid Argon detectors

Laboratory work

T600 detector

20 m 2001: First T600 module

Cooperation with industry

CERN CERN CERN

1 2 3 4 5

2010: ICARUS Operational in Hall B of LNGS

6

Japan_Dec 2010 Slide# : 4

Early neutrino physics at CERN_WANF(1997-98)

• Quasi-elastic events with a 50 litres LAr TPC in front of NOMAD:
• a quasi-elastic neutrino event;
• a multi-prong neutrino event reconstructed in 3D

Japan_Dec 2010 Slide# : 4

Japan_Dec 2010 Slide# : 5 Japan_Dec 2010 Slide# : 5

Reconstruction of Quasi-elastic LAr events

• Quasi-elastic neutrino events

in LAr have been reconstructed in the 50 litre ICARUS LAr-TPC exposed to the CERN-WANF beam in coincidence with the NOMAD experiment.

• Simulations, accounting for

Nuclear Fermi motion and re- interactions in nuclei, are found in good agreement with a 200 pure lepton-proton final state events with 1 proton TP > 50 MeV (range > 2 cm) and any number protons TP< 50 MeV.

Japan_Dec 2010 Slide# : 6

The ICARUS Collaboration

• A. Ankowski, K. Graczyk, C. Juszczak, J. Sobczyk

Wroclaw University of Technology, Wroclaw, Poland

• M. Antonello, P. Aprili, N. Canci, C. Rubbia, E. Segreto, C. Vignoli

Laboratori Nazionali del Gran Sasso dell’INFN, Assergi (AQ), Italy

• B. Baibussinov, M. Baldo Ceolin, S. Centro, D. Dequal, C. Farnese, A. Fava, D. Gibin, A. Guglielmi, G. Meng,
• F. Pietropaolo, F. Varanini, S. Ventura

Dipartimento di Fisica e INFN, Università di Padova, Via Marzolo 8, I-35131

• A. Cesana, A. Ferrari, P. Sala, A. Scaramelli, M. Terrani

Dipartimento di Fisica e INFN, Università di Milano, Via Celoria 2, I-20123

• L. Berzè, P. Benetti, E. Calligarich, R. Dolfini, A. Gigli Berzolari, A. Menegolli, C. Montanari,
• A. Rappoldi, G. L. Raselli, M. Rossella

Dipartimento di Fisica Nucleare,Teorica e INFN Università di Pavia, Via Bassi 6, I-27100

• F. Carbonara, A. G. Cocco, G. Fiorillo

Dipartimento di Scienza Fisiche, INFN e Università Federico II, Napoli, Italy

• K. Cieslik, A. Dabrowska, M. Szarska, D. Stefan, T. Wachala, A. Zalewska
• H. Niewodniczanski Institute of Nuclear Physics, Krakow, Poland
• G. Mannocchi, L. Periale, P. Picchi,

Laboratori Nazionali di Frascati (INFN), Via Fermi 40, I-00044

• A. Dermenev, S. Gninenko, M. Kirsanov

INR RAS, prospekt 60-letiya Oktyabrya 7a, Moscow 117312, Russia

• J. Holeczek, J. Kisiel, T. Szeglowski

University of Silesia, 12 Bankowa st., 40-007 Katowice, Poland

• D. Kielczewska, M. Posiadala

Warsaw Univeristy, Krakowskie Przedmiescie 26/28, 00-927 Warszawa, Poland

• T. Kozlowski, J. Lagoda, P. Mijakowski, T. J. Palczewski, P. Przewlocki, E. Rondio, J. Stepaniak, M. Szeptycka
• A. Soltan Institute for Nuclear Studies, 05-400 Swierk/Otwock, Poland
• W. Polchlopek

AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow, Poland

• F. Sergiampietri

Dipartimento di Fisica, Università di Pisa, Largo Bruno Pontecorvo 3, I-56127

• R. Sulej, K. Zaremba

Univeristy of Technology, Pl. Politechniki 1, 00-661 Warsaw, Poland

• D. B. Cline, B. Lisowski, C. Matthey, S. Otwinowski, Y. Seo, H. Wang, X. Yang

Department of Physics and Astronomy, University of California, Los Angeles, USA

Japan_Dec 2010 Slide# : 7 Japan_Dec 2010 Slide# : 7

ICARUS (CNGS2): the first large scale LAr experiment

• ICARUS represents a major milestone in the practical realization of a

large scale LAr detector. Successfully operated on surface in Pavia in 2002, it is now operational in the underground HallB of LNGS.

• The T600 at LNGS will collect simultaneously “bubble chamber like”

neutrino events events of different nature

• Cosmic ray events
• ≈ 80 ev/year of unbiased atmospheric CC neutrinos.
• Solar neutrino electron rates >5 MeV.
• Supernovae neutrinos.
• A zero background proton decay with 3 x 1032 nucleons for ”exotic”

channels.

• CERN beam associated events: 1200 νµ CC ev/y and 7-8 νe CC ev/year
• Observation of neu-tau events in the electron channel (with sensitivity

comparable to the one of OPERA.

• A search for sterile neutrinos.
• After CNGS2 runs during 2011 and 2012, the “next step” for the T600 is a

comprehensive search of sterile ν and anti-ν at the CERN PS.

+ LSND like sterile neutrinos τ -> eνν νν decays Likelihood weight

ν−e balanced events or ν−tau decays ?

Likelihood distributions may separate an hypothetical LSND excess from the expected presence of τ −> ενν decays

Japan_Dec 2010 Slide# : 9 Japan_Dec 2010 Slide# : 9

ICARUS T600 in LNGS Hall B

30 m3 LN2 Vessel 30 m3 LAr Vessel N2 liquefiers: 10 units, 40 kW cryo-power N2 Phase separator

Japan_Dec 2010 Slide# : 10 Japan_Dec 2010 Slide# : 10

T600 cryostats layout

Electronics (54000 channels) Pipe from safety magnetic disks Passive heaters LN2 Pumps LAr purification systems GAr purification systems

Japan_Dec 2010 Slide# : 11 Item Description 1 Drift ultra-pure LAr Volume (300 ton) 2 HV cathode (150 kV) 3 Wire chamber readout planes (3) 4 Drift field shaping rings 5 Light collecting PM’s 6 HV feed through (150 kV) 7 Aluminium Honeycomb container box 8 Evacuated volume (cold) 9 Supporting and insulating feet 10 Thermal insulation and containment 11 Chimneys for readout electronics

Item Description 12 Evacuation piping 13 Racks for electronic readout 14 Gas recirculation & purification 15 Supporting feet 16 Protective gridding 17 Nitrogen cooling circuits 18 Liquid Nitrogen storage 19 External supporting structure 20 Main basement 21 Nitrogen re-liquefaction system 22 Cryogenic plant 23 Liquid transfer pump 24 Oxysorb/Hydrosorb filter in liquid phase

Japan_Dec 2010 Slide# : 12 Japan_Dec 2010 Slide# : 12

Continuous waveform Recording

ICARUS front-end Electronics

F A D C F A D C

Twisted pair cables (~5m, 50pF/m) Liquid argon Gas Decoupling Boards (32 ch.) Front-end amplifiers (32/board); 1500 e.n.c Sense wires (4-9m, 20pF/m) VME board (18/crate)

4 Multiplexers (400ns x 8ch.)

10bit FADC 400ns sampling 1mV/ADC (~1000e-/ADC matches el. Noise) To storage 100 UHV feed-throughs: 576 channels (18 connectors x 32 + HV wire biasing) H.V. (<±500 V) New Design based on multi-layer PCB with blind holes: electrical continuity ultra high vacuum tightness Multi-event circular buffer (8x1ms)

Japan_Dec 2010 Slide# : 13 Japan_Dec 2010 Slide# : 13

Thirty years of progress........

Gargamelle bubble chamber ICARUS electronic chamber

Medium Heavy freon Sensitive mass 3.0 ton Density 1.5 g/cm3 Radiation length 11.0 cm Collision length 49.5 cm dE/dx 2.3 MeV/cm Medium Liquid Argon Sensitive mass Many ktons Density 1.4 g/cm3 Radiation length 14.0 cm Collision length 54.8 cm dE/dx 2.1 MeV/cm

LAr is a cheap liquid (≈1CHF/litre), vastly produced by industry LAr is a cheap liquid (≈1CHF/litre), vastly produced by industry

Bubble diameter ≈ 3 mm (diffraction limited) “Bubble” size

3 x 3 x 0.3 mm3

32 bar pressure Pulsed ≈ 1ms 32 bar pressure Pulsed ≈ 1ms no over-pressure Continuously sensitive no over-pressure Continuously sensitive Presently T600 with > 600 ton

• f LAr, running

underground at the LNGS Magnetic field replaced by high accuracy 3D calorimetry.

Japan_Dec 2010 Slide# : 14 Japan_Dec 2010 Slide# : 14

Summary of LAr TPC performances

• Tracking device
• Precise event topology
• Momentum via multiple scattering
• Measurement of local energy deposition dE/dx
• e / γ

separation (2%X0 sampling)

• Particle ID by means of dE/dx vs range
• Total energy reconstruction of the events

from charge integration

• Full sampling, homogeneous calorimeter

with excellent accuracy for contained events

RESOLUTIONS Low energy electrons: σ (E)/E = 11% / √ E(MeV)+2%

• Electromagn. showers: σ

(E)/E = 3% / √ E(GeV) Hadron shower (pure LAr): σ (E)/E ≈ 30% / √ E(GeV)

dE/dx distribution along a single muon track

T300 real event

µ e

Japan_Dec 2010 Slide# : 15 Japan_Dec 2010 Slide# : 15

Muon momentum resolution by multiple scattering

• Muon momentum resolution Δp/p=15% (A) from multiple

scattering [Kalman filter] has been measured for E < 0.5 GeV.

• The procedure, validated on stopping muons, has been extended

to higher energy with MC calculations; the resolution Δp/p can be as good as 10%, depending mainly on track length (B)

Japan_Dec 2010 Slide# : 16 Japan_Dec 2010 Slide# : 16

Electrons from muon decay

• Excellent resolution obtained from the measured decay

electron spectrum (Michel parameter) from muon decays

Precision calorimetry

Japan_Dec 2010 Slide# : 17 Japan_Dec 2010 Slide# : 17

The key feature of LAr imaging: very long e-mobility

• The main technological challenge of the

development of the cryogenic liquid Ar chamber is the capability of ensuring a sufficiently long free electron lifetime.

• Indeed the free electron path in a liquid is

≈ 600 times shorter than in a gas. For instance 10 ms lifetime corresponds to a 30 ppt (t=trillion !) of Oxygen equivalent.

• At 500v/cm, a 5m drift length corresponds

to a drift time of 3.1 ms (1.6 m/ms).

• The intrinsic bubble size (rms diffusion) is

given by

• The values for 5m drift are 〈σD〉≈ 1.1 mm

and σmax≈ 1.6 mm , tiny with respect to the wire pitch (≥ 2mm).

D mm

[ ] = 0.9 TD ms [ ]

Performance with 600 ton

Japan_Dec 2010 Slide# : 18 Japan_Dec 2010 Slide# : 18

“Purity”: status of the art in 2001

• During 2001 a first real size

test of the 1/2 of the T600 detector was performed on surface in Pavia.

• In the detector the drift

length was set to 1.5 m, corresponding to a drift time of about 1 ms.

• The purity performance at

that time is shown here, measured both with purity monitors and muon tracks.

2 ms

• A considerable progress over the last few years has

permitted to reach industrial purification techniques which are capable of a much better performance.

Japan_Dec 2010 Slide# : 19 Japan_Dec 2010 Slide# : 19

Recent progress in experimental purity achievements

• New industrial purification methods

have been developed at an exceptional level, especially remnants of O2 which have to be initially and continuously purified.

• Extremely high τele have been

determined with cosmic µ’s in a small 50 litres LAr-TPC.

• The short path length used (30 cm) is

compensated by the high accuracy in the observation of the specific ionization

• The result here reported is τele ≈21 ms

corresponding to ≈15 ppt, namely a ≈10-11 molecular impurities in Ar

Japan_Dec 2010 Slide# : 20 Japan_Dec 2010 Slide# : 20

ICARINO-Legnaro

• The measured value to the

experimental τele corresponds to an attenuation of about 10 % for a longest drift of 5 meters,

• pening the way to exceptionally

long drift distances.

Drift time Wire number

real event

τele= (21 ± 5) ms

LAr Purification in T600: an advanced technology

Slide: 21

Gas recirculation scheme Liquid recirculation scheme

Japan_Dec 2010

• Because of temperature (87 K)

most of the contaminants freeze

• ut spontaneously.
• Recirculation/purification (100

Nm3/h) of the gas phase (~40 Nm3) to block the diffusion of the impurities from the hot parts of the detector and from micro-leaks on the openings (typically located on the top of the device) into the bulk liquid.

• Recirculation/purification (4

m3/h) of the whole liquid volume (~550 m3) to reduce efficiently the impurities.

Japan_Dec 2010 Slide# : 22 Japan_Dec 2010 Slide# : 22

Cosmic µ interaction underground in ICARUS T600

Drift t coordinate (1.5 m) Drift t coordinate (1.5 m) Wire coordinate (0.8 m) Wire coordinate (0.4 m)

Japan_Dec 2010 Slide# : 23 Japan_Dec 2010 Slide# : 23

A “track good for purity” in the T600

Japan_Dec 2010 Slide# : 24 Japan_Dec 2010 Slide# : 24

Single track analysis: an example

e = 3.2 0.4

+0.6 ms

Japan_Dec 2010 Slide# : 25 Japan_Dec 2010 Slide# : 25

Free electron lifetime: experimental determination in T600

• Electron Lifetime is measured in the underground T600 detector

by the charge signal attenuation versus drift time in Collection view for through-going straight muon tracks (1 /(hour m2).

• Request for a track to be “good for purity”:
• At least 50 wires and 1200 t-sample both in Collection and

Induction2 views

• Reduced e.m. activity along the track: no delta-rays near the

track

• A simple model: uniform distribution of the impurities, internal

degassing, decreasing in time because of an external leak balanced by liquid recirculation (tele [ms] = 0.3 / N[ppb])

( )

I I R

t k k N dt dN

• +

+

• =

exp

τ τR

R:

: recirculation time of the full detector volume

kI and τI : related to the total degassing internal rate k : related to the external leaks

Japan_Dec 2010 Slide# : 26 Japan_Dec 2010 Slide# : 26

Purity Measurement results:West Module

The electron lifetime is still increasing:

• Internal degassing and external leak very small

Japan_Dec 2010 Slide# : 27 Japan_Dec 2010 Slide# : 27

The electron lifetime is ~ 2.7 ms in the last 2 months:

• The comparison with the West module: reduced internal degassing
• Possible external impurity contribution under investigation

Purity Measurement results: East Module

Japan_Dec 2010 Slide# : 28 Japan_Dec 2010 Slide# : 28

Purity Measurement: simple fit to data

West East Initial impurity [ppb] 0.771 ± 0.013 1.787 ± 0.035 External leak rate [ppt/day]

• 0. ± 0.33

2.1 ± 0.44 Initial internal degassing [ppt/day] 0.50 ± 0.015 0.80 ± 0.019 Degassing reduction time [days] 103.5 ± 2.25 213.4 ± 26.0 Recirculation time 1 [days] 5.86 ± 0.04 5.37 ± 0.05 Recirculation time 2 [days] 6.36 ± 0.06 5.92 ± 0.09 Recirculation time 3 [days] 5.85 ± 0.04 6.10 ± 0.03 Recirculation time 4 [days]

• 5.67 ± 0.09

Unaccounted difference in the degassing times ! Nominal recirculation time of purifier: 2 m3/h x 2 corresponding to ≈ 6 day cycle time

Japan_Dec 2010 Slide# : 29 Japan_Dec 2010 Slide# : 29

Reduced lifetime of the East module ?

ks(N2) ~ ks(O2)/760 For 0.5<E<3.0 kV/cm

• The East module has undergone some

unwanted, accidental events:

• Initial purity much lower before

recirculation

• Recovery from HV feedthrough

failure

• Accidental overpressure with loss
• f about 2 m2 of LAr to air
• Both modules have similar purification

rates (full recirculation in 6 days)

• The shorter lifetime ( 3ms) is

remarkably constant over many weeks

• Many alternatives but the presence of

some “relic” impurity not cleared by the purifier very likely (N2, H2O, CO2, ?)

• Gas chromatograph measurements in

gas are under progress

Japan_Dec 2010 Slide# : 30 Japan_Dec 2010 Slide# : 30

CNGS2 runs during 2010

• At every CNGS cycle 2 proton spills lasting 10.5 µs each, 50 ms apart.
• Trigger with the photomultiplier signal for each chamber: low threshold

discrimination (~ 30 mV), coincident with a 60 µs long beam window.

• Oct. 1st ÷ Nov. 22nd: 8 ⋅ 1018 pot delivered,

5.9 ⋅ 1018 pot collected with detector lifetime up to 90% since Nov. 1st.

Japan_Dec 2010 Slide# : 31 Japan_Dec 2010 Slide# : 31

CNGS events timing w.r.t. CERN proton extraction time

• Very narrow beam distribution: only 10 µs wide ≈ spill duration (10.5 µs)
• Mean offset value (2.404 ms) in agreement with ν t.o.f. (2.437 ms) in view
• f ~ 40 µs fiber transit time from ext. LNGS labs to Hall B (8km)

10.5 µs Perfect synchronism between CERN and LNGS (730 km distance)

Collection view Wire coordinate (8 m) Drift time coordinate (1.4 m) CNGS ν beam direction

νµ CC

Japan_Dec 2010 Slide# : 32 Japan_Dec 2010 Slide# : 32

CNGS “first” neutrino interaction in ICARUS T600

Selected events are reconstructed, analyzed and qualify reconstruction /analysis programmes

Japan_Dec 2010 Slide# : 33 Japan_Dec 2010 Slide# : 33

Low energy CNGS νµ CC interaction

1.8 m 0.5 m

Evis ~ 9 GeV

Electron lifetime and quenching accounted for

Collection views (not to scale!)

Japan_Dec 2010 Slide# : 34 Japan_Dec 2010 Slide# : 34

CNGS νµ CC interaction in ICARUS T600

µ continuing in adjacent TPC chamber

Drift t coordinate (1.5 m) Wire coordinate (4 m)

Japan_Dec 2010 Slide# : 35 Japan_Dec 2010 Slide# : 35

CNGS νµ CC interaction in ICARUS T600

Wire coordinate (9.6 m) Drift t coordinate (1.5 m)

Japan_Dec 2010 Slide# : 36 Japan_Dec 2010 Slide# : 36

CNGS NC interaction in ICARUS T600

Wire coordinate (2.2 m) Drift t coordinate (1.5 m)

Japan_Dec 2010 Slide# : 37 Japan_Dec 2010 Slide# : 37

Very low energy CNGS neutrino interaction

Total visible energy: 770 MeV (including quenching and electron lifetime corrections)

Very small event

Japan_Dec 2010 Slide# : 38 Japan_Dec 2010 Slide# : 38

Outline of the 3D reconstruction

• Complement of 2D reconstruction
• It is based on Polygonal Line Algorithm (PLA) [1]
• The procedure of sorting hits along 2D tracks independly

in each view:

• As a result of the PLA application
• PLA-FIT through hits of a track
• both hits and hit projections to the fit are sorted along

the track

• 3D reconstruction: Linking hit projections between views

according to

• drift sampling
• sequence of hits

[1] http://www.iro.umontreal.ca/~kegl/research/pcurves/

Japan_Dec 2010 Slide# : 39 Japan_Dec 2010 Slide# : 39

Polygonal 3D Line Algorithm

initialization projection vertex optimization convergence?

k > c ?

END add vertex vi

first PC segment (Principal Component)

N N Y Y local squared distance to hits local angle penalty term

( ) ( ) ( )

i i n i

k n v v v P 1 1 1 G + +

• =
• segment number k exceeds given ratio c = k/n

track hits number: longer tracks usually are more straight

http://www.iro.umontreal.ca/~kegl/research/pcurves/

Japan_Dec 2010 Slide# : 40 Japan_Dec 2010 Slide# : 40

Example of the PLA fit: kaon event in 2001 run.

Polygonal Line Algorithm: short tracks

kaon muon

• Blue points: hits in

collection

• Red points /segments:

vertex/segments of the PLA fit

Japan_Dec 2010 Slide# : 41 Japan_Dec 2010 Slide# : 41

Neural Network particle identification: χ2

• Particle identification is based on:
• distance between nearby 3D hits: dx
• 3D hits and charge deposition : dE/dx
• classify single ith point on the track

pi : [Ek, dE/dx] → nni : [ P(p), P(K), P(π), P(µ)]

• Average M output vectors for the points

NN = S(nni)/M

• Identify track as particle corresponding to

max(NN)

• Energy reconstruction with simulation for

quenching

pid

p K π µ

efficiency [%] purity [%] MC p 481 4 99.2 98.0 K 10 380 97.4 99.0 π 196 40 83.1 98.5 µ 3 216 98.6 84.4

Very high identification efficiency for p, k, pion+muon Very high identification efficiency for p, k, pion+muon

Japan_Dec 2010 Slide# : 42

X Y Z

3D

Japan_Dec 2010 Slide# : 42

Run 9392 Event 106

• Total deposited energy 887 MeV
• Total reconstructed p

929 MeV/c at about 30° away from the CNGS beam direction

Track 1 (prob. π, decays in flight) 2 (π) 2a (µ) 2b (e) 3 (µ) 4 (p) 5 (p) 6 (?) (merged with vtx) Ek [MeV] 136.1 26 79.1 24.1 231.6 168 152 Range [cm] 55.77 3.3 17.8 10.4 99.1 19.2 16.3 2.9

2: π → µ µ → e

Japan_Dec 2010 Slide# : 43 Japan_Dec 2010 Slide# : 43

Collection Total visible energy 4.5 GeV

Run 9927 Event 572

Track 1 (µ) 2 3 (p)

• Sec. vtx.

4 5 (µ) 6 (K) 7 8 Edep[MeV] 2701.97 520.82 514.04 797 76.99 313.9 86.98 35.87 283.28 cosx 0.069 0.054

• 0.001

0.009 0.000 0.414

• 0.613

cosy

• 0.040
• 0.420

0.137

• 0.649
• 0.239

0.793 0.150 cosz

• 0.997
• 0.906
• 0.991

0.761

• 0.971
• 0.446
• 0.776

Induction2

π0

Conversion distances 6.9 cm, 2.3 cm

Primary vertex (A): very long (1), e.m. cascades (2), pion (3)

Secondary vertex (B): The longest track (5) is a µ coming from stopping k (6). µ decay is

• bserved

A B

close-up of two e.m. showers

3D

Japan_Dec 2010 Slide# : 44 Japan_Dec 2010 Slide# : 44

Beyond ICARUS-T600

• The operation of the T600 demonstrates the large number of

important milestones which have been achieved in the last several years, opening the way to the development of new line

• f modular elements, which may be progressively extrapolated

to the largest conceivable LAr-TPC sensitive masses.

• Based on the T600 experience, the ICARUS collaboration has

now proposed a next generation LAr-TPC in tens of kt scale: the MODULAr project. (Astroparticle Physics 29 (2008) 174)

• The new detector, using the present CNGS beam off axis

with several 5 kton units will maintain the majority of components developed with industry for the T600.

• This detector might be easily upgraded in the far future to a

larger scale, depending on the potential physics goals.

Japan_Dec 2010 Slide# : 45 Japan_Dec 2010 Slide# : 45

The MODULAr detector

• MODULAr will be initially composed by four identical modules located in a

new shallow-depth cavern, 10 km off axis from existing CERN/CNGS beam.

• Each module is a scaled-up version of the T600 (x 2.663):
• 8 X 8 m2 cross section and about 60 m length
• LAr active mass: 5370 ton
• 4 m electron drift (2.66 ms), Edrift = 0.5 kV/cm, H.V.: -200 kV
• 3-D imaging similar to T600 but 6 mm pitch (three planes, ~50000 chs)

Japan_Dec 2010 Slide# : 46 Japan_Dec 2010 Slide# : 46

MODULAr Sensitivity to θ13 and δCP

Event rates in MODULAr (20 kt, 5 y, 1.2 1020 pot/y, sin2(2θ13)=0.1) 5% beam systematics. ΔE/E = 15% νµ CC e bkg Signal S/√(bkg) 5700 28 250 47

Japan_Dec 2010 Slide# : 47 Japan_Dec 2010 Slide# : 47

Nucleon decay : single event capability

p→e+ π0 p→νK+ n→νK0

p → K+ νe

65 cm

Japan_Dec 2010 Slide# : 48 Japan_Dec 2010 Slide# : 48

Channel 90%CL-5y (pdg 90%CL) p

+

4.4 1033 (2.5 1031) p

+K+

1.1 1034 (2.5 1032) n e- K+ 1.3 1034 (3.2 1031) n

+

• 6.0 1033

(1.0 1032) n 4.4 1033 (1.1 1032)

Nucleon decay expectations

• LAr-TPC provides a much more

powerful bkg rejection w.r.t.

• ther techniques. It can perform

a large variety of exclusive decay modes measurements in bkg free mode.

• With 1.2 1034 nucleons, MODULAr

is well suited for channels not accessible to Č detectors due to the complicated event topology,

• r if the emitted particles are

below the Č threshold (e.g. K+)

5 years exposure

Japan_Dec 2010 Slide# : 49 Japan_Dec 2010 Slide# : 49

New physics with the T600 detector.

• According to expectations, the present exploitation of

ICARUS in the Hall-B of LNGS will be carried out during 2011 and 2012.

• Neutrinos have been the origin of an impressive number of

“Surprises”. The sum of the strengths of the coupling of different ν is very close to 3, but its number may be altered by the additional presence of other “sterile” neutrinos.

• It is only because the masses of known neutrino species are so

small, that their contribution to the Dark Matter of the Universe can be neglected. The additional presence of massive sterile neutrinos may for instance contribute to Dark Matter.

• The LSND and the MiniBooNE experiments have indicated the

presence of anomalies, so far unexplained.

• The novelty of our technology is offering other interesting

alternatives with a refurbished ν beam at the CERN-PS.

Japan_Dec 2010 Slide# : 50 Japan_Dec 2010 Slide# : 50

A dual LAr detector at different distances at the CERN-PS

• The recent results at Fermilab open major questions, some of

which in apparent agreement with the initial LSND puzzle.

• MINIBOONE introduces other significant differences

with respect to the standard neutrino expectations.

• MINOS is also hinting at some anomalies which could be

explained by sterile neutrino, CPT or by something else.

• Apparent disagreement between Gallium+Bugey (CPT ?).
• The LAr-TPC may be the solution of these puzzles: a novel

search is proposed after the success of ICARUS technology.

• Our proposal is based on two strictly identical LAr-TPC

detectors observing the νe signal both for νµ and νµ in the Near and Far positions, the first with ≈ 150 tons at 127 m, the second with ≈ 600 tons (T600) placed 850 m away. Cross sections and experimental biases cancel out in the comparison.

Japan_Dec 2010 Slide# : 51 Japan_Dec 2010 Slide# : 51

Two detectors at the PS neutrino beam

Two positions are foreseen for the detection of the neutrinos The far (T600) location at 850 m from the target: L/E ~ 1 km/GeV; The new location at a distance of 127 m from the target: L/E 0.15 km/GeV

T600 T150

Japan_Dec 2010 Slide# : 52

The new T150 detector to be constructed

Item Description 1 Drift ultra-pure LAr Volume (150 ton) 2 HV cathode (150 kV) 3 Wire chamber readout planes (3) 4 Drift field shaping rings 5 Light collecting PM’s 6 HV feed through (150 kV) 7 Aluminium Honeycomb container box 8 Evacuated volume (cold) 9 Supporting and insulating feet

Item Description 10 Thermal insulation and containment 11 Chimneys for readout electronics 12 Evacuation piping 13 Racks for electronic readout 14 Gas recirculation & purification 15 Supporting feet 16 Protective gridding 17 Nitrogen cooling circuits 18 Liquid Nitrogen storage 19 External supporting structure 20 Main basement

Japan_Dec 2010 Slide# : 53 Japan_Dec 2010 Slide# : 53

Advantages of a dual detector in real time

• In absence of oscillations, apart some beam related small

spatial corrections, the two spectra are a precise copy of each

• ther, independently of the specific experimental event

signatures and without any Monte Carlo comparison.

• Therefore an exact, observed proportionality between the

two νe spectra implies directly the absence of neutrino

• scillations over the measured interval of L/E.

(arXiv:0909.0355)

Perfect identity between the near and far positions, dominated by the k- decay spectra Perfect identity between the near and far positions, dominated by the k- decay spectra

Japan_Dec 2010 Slide# : 54 Japan_Dec 2010 Slide# : 54

Determination of both the Δm2 and sin2 2θ values

• It appears that the present proposal,

unlike LNSD and MiniBooNE, can determine both the mass difference and the value of the mixing angle.

• Very different and clearly distingui-

shable patterns are possible depending on the values in the (Δm2 – sin2 2θ) plane.

• The intrinsicν- e background due to the

beam contamination is also shown.

• The magnitude of the LNSD expected
• scillatory behaviour, for the moment

completely unknown, is in all circumstances well above the backgrounds, also considering the very high statistical impact and the high resolution of the experimental measurement.

Japan_Dec 2010 Slide# : 55 Japan_Dec 2010 Slide# : 55

Comparing sensitivities (arXiv:0909.0355)

Expected sensitivity for the proposed experiment exposed at the CERN-PS neutrino beam (left) for 2.5 1020 pot and twice as much for anti-neutrino (right) . The LSND allowed region is fully explored both for neutrinos. The expectations from one year of at LNGS are also shown.

Japan_Dec 2010 Slide# : 56 Japan_Dec 2010 Slide# : 56

Thank you !