September 11th, 2006 LNGS and the Neutrinos from CERN OPERA 1 OPERA scillation Project with Emulsion-tRacking Apparatus
Jan 20, 2016
September 11th, 2006 LNGS and the Neutrinos from CERN OPERA 1
OPERAOscillation Project with Emulsion-tRacking Apparatus
September 11th, 2006 LNGS and the Neutrinos from CERN OPERA 2
OPERA is an International Collaboration
37 INSTITUTIONS, ~160 PHYSICISTS
IPNL, IRES, LAPP
INR ITEPJINR, Obninsk
Zagreb
L’Aquila, Bari, Bologna, Napoli, Padova, Roma,
Salerno, LNF, LNGS
BernNeuchatel
Zurich
Brussels
Hamburg, Münster,Rostock
Sofia
Aichi, TohoKobe, NagoyaUtsunomiya
Technion Haifa
METU Ankara
IHEP BeijingShandong
Gyeongsang University
September 11th, 2006 LNGS and the Neutrinos from CERN OPERA 3
37 INSTITUTIONS, ~160 PHYSICISTS
IPNL, IRES, LAPP
INR ITEPJINR, Obninsk
Zagreb
L’Aquila, Bari, Bologna, Napoli, Padova, Roma,
Salerno, LNF, LNGS
BernNeuchatel
Zurich
Brussels
Hamburg, Münster,Rostock
Sofia
Aichi, TohoKobe, NagoyaUtsunomiya
Technion Haifa
METU Ankara
IHEP BeijingShandong
Gyeongsang University
OPERA is an International Collaboration
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Neutrinos Oscillations : Flavor change for massive Neutrinos
This property of massive neutrinos has been proposed by B. Pontecorvo (1950)
After 50 years of a long search with various experimental technics• Solar neutrinos (i.e. GALLEX at LNGS)• Atmospheric neutrinos (i.e. MACRO at LNGS)• Nuclear Reactors neutrinos • Accelerator neutrinos
The existence of the Neutrinos Oscillations has been established
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What is the goal of OPERA
Once the oscillations established, a large international program has been set for checking all parameters of the flavor transitions:
• Japan ( KEK to Super-Kamiokande) , US ( Fermi Lab to MINOS )
μ disappearance
• Europe ( CERN to Gran Sasso )
τ appearance OPERA
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Detection of the appearance signal
Two conflicting requirements: Large mass low Xsection High granularity
signal selection background rejection
Target:1800 tons, 5 years running
• 30 000 neutrino interactions• ~150 interactions• ~15 identified• < 1 event of background
Toplogy selection:
Kink signature
The challenge is to identify interactions from interactions
-
Decay “kink”
-
~1 mm
oscillation
-
September 11th, 2006 LNGS and the Neutrinos from CERN OPERA 7
8.3 Kg
Pb
Emulsion layers
1 mm
•ECC : target basic component• Em Provides high space resolution + Lead active target mass•Compact and modular structure
OPERA bricks 1 ECC= 56 Pb + 57 emulsions
2 emulsion layers (44 m thick)poured on a
200 m plastic base
12.5cm
10.2cm
10 X0’s
Interaction From NUMI exposure
Electron shower
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OPERA/CNGS1 : an hybrid detector
What the brick cannot do: trigger for a neutrino interaction muon identification and momentum/charge measurement need for an hybrid detector
supermodule
8 m
Target Trackers
Pb/Em. target
Emulsion analysis:
Vertex, decay kink e/ ID, multiple scattering, kinematics
Extract selected brick
Pb/Em. brick
8 cm Pb 1 mm
Basic “cell”
Emulsion
Electronic detectors:
Brick finding muon ID, charge and p
Link to mu ID,Candidate event
Spectrometer
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Structure of the OPERA Experiment
31 target planes / supermodule (in total: 206336 bricks, 1766 tons)
TargetsMagnetic Spectrometers
Proposal: July 2000, installation at LNGS started in May 2003First observation of CNGS beam neutrinos : August 18th, 2006
SM1 SM2
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OPERA Super-module
OPERA Trackers in pictures & numbers
details of the first spectrometer
5900 m² scintillator detectors – 3050 m² Resistive Plate Chambers8064 7m long drift tubes - ~2000 tons of Fe
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August 2006 : first neutrinos from the CNGS detected
50 ms10.5 s 10.5 s
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Δt first extraction (ns)
50 ms
Ext1 Ext2
Cosmic rays background events
Zoom on the spill peaks
Δt closest extraction (ns)
10 s
Event selection by using GPS timing informations
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Beam event
CC event originated from material in front of the detector (BOREXINO, rocks)
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CC event in the first magnet
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CC event in the first target
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Muons bundle from cosmic rays
Cosmic rays event can be easily isolated using their topology
Beam events:~horizontal tracks
Cosmic rays induced events:Mostly down going
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Conclusions
• The CNGS beam is operating smoothly with very good quality• The tracking detectors of OPERA are taking data with practically no dead time • More than 300 beam correlated events have been registered with a clean time distribution• The recorded events show the expected tracking performances• Correlation between tracks measured in the tracking detectors and emulsions installed in the target have been observed• OPERA is now preparing the next step:
observing neutrino interactions in the Emulsion Cloud Chamber bricks
Next step : end of october run !!!
September 11th, 2006 LNGS and the Neutrinos from CERN OPERA 18
Brick production
CS box
Brick
Emulsion films
Lead boxes
BAM piling/pressing section
BAM wrapping section
Starting now:• 12 106 emulsions & lead plates• 200 000 bricks to be produced• production rate : 1000/day
10 months for filling the detector
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Brick insertion, extraction, processing,
Brick Manipulating System
Emulsion developping lab
Vacuum sucker vehicle
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Event reconstruction in the brick
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The messenger of the starsis revealing great and wonderful spectaclesand incite everyone to look up at these …
For 50 years, by recording neutrinos from the sun, the Super-Novae, cosmic rays we improved our understanding in Astrophysics and Cosmology
In addition, neutrinos gave us a present by revealing their properties: this is opening a new field of research in fondamental physics for the next 50 years which will also have profound consequences in the understanding of the Universe