OPERA : CERN-LNGS Long Base νμ→ντ Appearance Experiment

COLLABORATION

36 groups~ 165 physicists

RussiaINR Moscow, ITEP Moscow, JINR Dubna, Obninsk

BelgiumIIHE(ULB-VUB) Brussels

FranceLAPP Annecy, IPNL Lyon, LAL Orsay, IRES Strasbourg

Germany *Berlin, Hagen, Hamburg, Münster, Rostock

IsraelTechnion Haifa

ItalyBari, Bologna, LNF Frascati, L’Aquila, LNGS, Naples, Padova, Rome, Salerno

JapanAichi, Toho, Kobe, Nagoya, Utsunomiya

SwitzerlandBern, Neuchâtel

TurkeyMETU Ankara

ChinaIHEP Beijing, Shandong

CroatiaZagreb University

BulgariaSofia University

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OPERA : CERN-LNGS Long Base νμ→ντ Appearance Experiment

Motivations:

• Direct observation of νμ -> ν oscillation by detection of ντ+ Pb CC

interaction in initially pure νμ beam (0.8% νe, 2% νμ)

•νμ -> νe observation: θ13 measurement

OPERA : CERN-LNGS Neutrino Beam (CNGS)

4.5x1019 pot / year<E> ~ 17 GeV

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• Emulsion Cloud Chamber (ECC)– Emulsions for tracking, passive material as target

– Basic technique established:

• charmed “X-particle” first observed in cosmic rays (1971)

• DONUT/FNAL beam-dump experiment: events observed

• m2 = (1.3 - 3) x 10-3 eV2 Mtarget ~ 2 kton

– large detector sensitivity, complexity

– modular structure (“bricks”): basic performance is preserved

Pb

Emulsion layers

1 mm

Experience with emulsions and/or searches : E531, CHORUS, NOMAD and DONUT

Experimental technique

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8 m

Pb/Em. target

Electronic detectors: target tracker, μ spectrometer, veto counters

find the brick with interaction ID, charge & p

Emulsion analysis vertex decay kink e/γ/μ/π ID, multiple scattering, kinematics

Extract selected brick  

Pb/Em. ECC brick

8 cm

Pb1 mm

Basic “cell”

Emulsion

OPERA Detector: Supermodule structure

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Underground assembly space

(2003 - 2006)

4 m

cor

rid

or

48 m

Hal

l B

Borexino

Hal

l C

Pb-emulsion stacking

brick packing

BAM

Emulsion storage

OPERA Detector: Disposition in LNGS underground lab

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31 target planes / spectrometer (206336 bricks, 1766 tons)

Front damping structureRear damping structure

Electronic barrack

Mechanical structure and risk analysis studyaccepted by safety authorities

OPERA Detector: Disposition in LNGS underground lab

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ECC Brick

10X0 ( 57 emulsion films )

Packing Options:VacuumMechanical

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Day by day experiment operation scheme

Emulsion Scanning stationslocate interaction detectionGran Sasso

tag interaction extract ECC brick

ECC brick

30bricks/day cosmic ray exposure develop emulsion sheet etc.

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OPERA Event rate

OPERA

1.766 ktons

νμC

C

24300

νμN

C

7300

νμC

C

510

νeC

C

194

νeC

C

17

__

__

5 years running @ 4.5 1019 /yearin shared mode

Δm2 OPERA

1 x 10-3 eV2 24

2 x 10-3 eV2 95

3 x 10-3 eV2 214

ντCC interactions

efficient beam monitoring

32300 Possible improvements:• proton intensity increase 1.5• running in dedicated mode 1.7

up to 80 events per day in OPERAto be taken into account for the scanning power

2.55

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Number of events: full mixing, 5 years run @ 4.5(6.76)x1019 pot / year

signal

(m2 = 1.3 x 10-3 eV2)

signal

(m2 = 2.0 x 10-3 eV2)

signal

(m2 = 3.0 x 10-3 eV2)BKGD

Final Design 3.1(4.7) 7.3(11) 16.4(24.6) 0.7(1.06)

5 YEARS 5 YEARS x 1.5

4

4

33

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CNGS schedule

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•Spectrometer :Magnet, RPC, XPC and Precision Tracker•Veto and Beam monitoring•Target : Brick wall and Target Tracker•DAQ•Brick production and Handling•Scanning and Computing

OPERA construction tasks and schedule

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OPERA construction tasks and schedule

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Spectrometer construction

slabs

base

coil

Fe(5 cm)

RPC

12 Fe slabs

in total 8.

2 m

B=

1.5

5 T

Total Fe weight

~ 1 kton

Tests at Frascati lab

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Spectrometer construction Aug 2003

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Spectrometer construction Dec 2003

Precision tracker

Electronics • FE : board ready• TDC : chip tested, board being designed• DAQ : running• HV board : final design in progress

Full size prototypeas seen from the top

Performance:• efficiency: 99.1%• resolution: 300 μm

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XY planes, 7000m2 in total32256 Scintillator strips 7m x 2.5cm x1cmAMCRYS-H (Kharkov) + Kuraray WLS

1000 MaPMT Hamamatsu 64channelsDedicated Front End electronics for gain correction Autotriggerable and threshold @ 1/5 p.e

7m

Target tracker

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Target tracker first wall constructed (Strasbourg)

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• Produce about 8 modules/week.• Delivery at GS (modules already calibrated):

1. 16 modules February 2004 2. 56 modules May 20043. 56 modules July 20044. 56 modules September 20045. 56 modules November 20046. 56 modules January 20057. 56 modules March 20058. 56 modules May 20059. 56 modules July 200510. 40 modules September 2005

TT installation: 31/03/2004 to 18/01/2006

TT Walls will be mounted outside (about 15 walls prepared in advance) and slided inside the detector after each brick wall installation.

Target tracker delivery

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100 Mbits switch

1) A Smart (Ethernet capable) F/E card TT : at the PM level RPC, PT : plane or station level

2) A distributed synchronization scheme (time + deterministic commands)

3) A network architecture with different levels of switches up to the event building work stations

Same architecture for : target tracker, RPC and Precision tracker

The 3 ingredients of the DAQ architecture

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Pb

1 mm

Lead from Boliden

Mass production starts April 2003 (~150 000 m2)

Refreshing done in the Tono Mine in Japan : 2 years durationOne batch sent to LNGS every 2 months starting august 2003 emulsion storage ready @ LNGS (Hall B) june 2003

125mm

100mm

ECC components: emulsion & lead

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Naples-Frascati wall

VV cable

VV cable loop driving system

CCD Camera

The Vacuum sucker Vehicle (VV)

50 bricks/day~ 3 hours

Brick Manipulator prototype (LAPP Annecy)

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Routine 5cm2/hrNear future 20cm2/hr

S-UTS prototype at Nagoya

Dedicated hardwareHard coded algorithms

European prototype

Commercial productsSoftware algorithms

~ 2mradx ~ 0.5m

Emulsion scanning

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Emulsion scanning: ντ→τ-→- simulated & reconstructed event

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1. november 2003 started SM1 Magnet RPC installation2. June 2004 starts SM1 Target installation3. January 2005 BAM and BMS installation 4. July 2005 starts filling bricks

Important milestones

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Important Physics Program• First evidence of - appearance in few years data taking

• In a five years run: 7(11) signal (@2.0 x 10-3 eV2) and 0.7(1.) background events

• Studies to improve efficiency and to reduce the background • Multi prong decay channel under study• Measurement of 13 ( See talk by P.Migliozzi )

Detector construction and installation• Mass production started• Large and complex detector installation started • Detector (and CNGS beam !) will be ready in 2006

Conclusions

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OPERA Sensitivity

5 years

3 yearsm2 = 1.2x10-3 eV2

at full mixing

sin2 (2) = 6.0x10-3

at large m2

5 years data taking

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Brick Assembling Machine (BAM) schedule

Final specifications: December 2002  End of market search: March 2003

Technical audit: April 2003  Call for tenders: May to October 2003 Firm selection: November 2003 Ordering: December-January 2003 Construction and tests in the firm: January 2003 to February 2005 Delivery at Gran Sasso laboratory: March 2005 Assembly, installation: April 2005

Production acceptance tests at Gran Sasso: May to July 2005 Brick mass production: September 2005 to August 2006