OPERA O scillation P roject with E mulsion-t R acking A pparatus

September 11th, 2006 LNGS and the Neutrinos from CERN OPERA 1

OPERAOscillation Project with Emulsion-tRacking Apparatus


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


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


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


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


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

-


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


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


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


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


August 2006 : first neutrinos from the CNGS detected

50 ms10.5 s 10.5 s


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


Beam event

CC event originated from material in front of the detector (BOREXINO, rocks)


CC event in the first magnet


CC event in the first target


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


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 !!!


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


Brick insertion, extraction, processing,

Brick Manipulating System

Emulsion developping lab

Vacuum sucker vehicle


Event reconstruction in the brick


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

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OPERA O scillation P roject with E mulsion-t R acking A pparatus