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