1

Status of the OPERA Status of the OPERA long-baseline long-baseline

neutrino experimentneutrino experimentMagali Besnier

PIC 07- Annecy

June 27th 2007

2

Search for tauneutrino appearance at Gran Sasso laboratory

in a pure muon neutrino beam produced at CERN (732 km)

First direct observation of First direct observation of oscillationoscillation

37 INSTITUTS, ~160 PHYSICISTS

OPERAOscillation Project with Emulsion tRacking Apparatus

International Collaboration (Europe + Japan)

IIHE (ULB-VUB), Brussels Sofia IHEP Beijing, Shandong IRB Zagreb LAPP Annecy, IPNL Lyon, IRES Strasbourg Berlin Humboldt, Hagen, Hamburg, Münster, Rostock Technion Haifa Bari, Bologna, LNF Frascati, L’Aquila, LNGS, Napoli, Padova, Roma La Sapienza, Salerno Aichi, Kobe, Nagoya, Toho, Utsunomiya INR Moscow, ITEP Moscow, JINR Dubna, Obninsk Bern, Neuchâtel, Zurich METU Ankara

Possibility of Possibility of eeoscillation search for oscillation search for 1313 measurement measurement

3Hadron stopHadron stop

HornHorn

Civil engineering completed (June ’03)

Hadron stopper and decay tube installed (June ’04)

Target section completed in 2006 (first CNGS beam in August 2006)

Decay tube Decay tube vacuum tests successfulvacuum tests successful

CNGS beam (CERN Neutrino to Gran Sasso)

vacuum 4.5 1019 p.o.t. /year

700 m 100 m 1000m 67 m

400GeV

Ø at GS=2km 3.2° angle

To Gran Sasso

4

P(CC) m2

23 = 2.5 10-3

eV²

Flux at Gran Sasso (given by Fluka)

flux

CNGS beam (CERN Neutrino to Gran Sasso) 4.5 1019 p.o.t. /year

Number of expected events at Gran Sasso (0-100 GeV):

(before reconstruction and detection efficiencies)

N CCyr/kT

N eCCyr/kT

N CCyr/kT

.Detection of CC interaction and direct observation of decay topology

.High background rejection

(17.4%) e- (17.8%)

h- n (49.5%) n() (14.5%)

decay kink

~ 0.6

mm

appearance signature

5

OPERA Performances for oscillationoscillation

channel Signal (m2 (eV2)) .BR Background

1.9 10-3 2.4 10-3 3.0 10-3 e 2.7 4.3 6.7 3.7% 0.23 2.2 3.6 5.6 3.1% 0.23 h 2.4 3.8 5.9 3.3% 0.32

3h 0.7 1.1 1.7 1.0% 0.22 total 8.0 12.8 19.9 11.1% 1.00

full mixing, 5 years run @ 4.5x1019 pot / year

Number of expected signal and background events

Most important background : charm particle production

Best value ofm223

= 2.5 10-3 eV²3 range : 1.9 - 3.2 10-3 eV²

T.Schwetz, hep-ph/0606060

6

rock thickness 1400m (3800 m.w.e.)cosmic muon flux: 1/m2/h

OPERA (CNGS1)

ICARUS (CNGS2)

Hall C

Hall B

BOREXINO

OPERA detector at LNGS (Notional Laboratories of Gran Sasso, Italy, 120 kms from Rome)

spectrometer: Dipolar magnet + RPC chambers

Target Trackers

Pb/Em. target

Precision tracker: Drift tubesB=1.6 T

2 super modules

1 super module = 31 walls + 31 Target Tracker + 1 muon spectrometer (21 RPC planes + 6 drift tube planes)

206 336 bricks

Lead target : 1.8 kTon ~6000 CC/yr

52*64 bricks/wall

p/p < 20% for E<50GeV

brick(56 Pb/Em. “cells”)

8 cm (10X0)

scintillator strips

brick wall

module

7

OPERA bricks : main target detector component

2mm

6mm

Emulsion Cloud Chamber (ECC) : 1 ECC brick = 56 sheets Pb + 57

photographic emulsions

Pb

Emulsion layers

1 mm 12 M emulsion films and12 M thin lead foils

byFuji Film (Japan)JLGoslar (Germany)

This technology allows a spatial micrometric resolution, and a 3D reconstruction of particle

tracks, necessary for detection

12.5 cm

8 cm

8.6 kg

10 cm 12.5cm10.2cm

2 emulsion layers (44 m thick) poured on a 200 m plastic base

The most precise trackerThe most precise tracker

Résolution (microtracks) spatial : 0.06 µm Angular : ~ 2 mrad

Vertex position resolution : ~1µm in transverse plane

- Measurement of hadrons momenta by MCS- dE/dx pion/muon separation at low energy- Electron identification and energy measurements for electrons and photons

Reconstructed electronic

shower

8

BAM (Brick Assembling Machine)Automatic

lead/emulsion piling in a dark room (500-700

bricks/day)

Insertion and extraction of bricks following intelligent

procedures.

The BMS(Brick Manipulator System)

one robot on each side of the

detector

Target preparation

Daily

total

Begining 2007 now

25000

30000

20000

15000

10000

5000

Brick production and insertion

9

Detector today : electronics fully instrumented and testedBrick filling on the way : 27000 Bricks already inserted

LNGS Hall C

10

20-30 bricks extracted / day

selection of the interaction brick provided by time

correlation of electronic detectors

Emulsion Development

of candidate bricks at Gran Sasso (surface

facilities)

Example of a vertex in emulsion

Emulsion Scanning with automated microscopes :

15 laboratories in Europe and Japan

Emulsion shipment

OPERA event analysis procedure

0 max

p.h.

Brick finding :

31 tracking scintillator planes (TT)/super modules

Trigger(>99%) + Brick finding (7080%)

Neutrino events in OPERA-like bricks (PEANUT test-beam)

Salerno scanning lab analysis

NUMI beam at low energy configuration

Scanning labs performance tests and improvements with :

-/e test-beams- test-beam-cosmic runs

11

First OPERA results with CERN neutrino beam

cosmicsBeam events

Positive electronic tests during first beam run (August 06 : 0.084 1019

integrated pot)

Next CNGS run : Autumn 2007

interaction in magnet (Fe)

More than 300 registred events correlated in time with beam : interactions inside the rock and inside the detector (TT and spectrometers)

First events from the CNGS neutrino beam detected in the OPERA experiment R. Acquafredda et al 2006 New J. Phys. 8 303

12

Muon track inside emulsions

First OPERA results with target bricks from cosmic run (May 07)

April 17th- May 15th :

~30 bricks extracted

18 scanned

8/18 muons already found in emulsions

Cosmic muons in OPERA detector (ray bandle)

< 1 event per day inside the acceptance ! ~20 ‘good’ bricks per month

first data confirm the good accuracy of the ED predictions

Prediction accuracy :• Δx = 5.5 mm (along the tray)• Δy = 0.4 mm (vertical direction)• Δθx = 16.6 mrad• Δθy = 24.8 mrad

13

ConclusionConclusionOPERA is the first experiment for appearance in a beam

Hybrid detector with passive lead target and active electronic detectors

Electronic parts fully instrumented and tested

27000 Bricks yet inserted in the detector - full detector expected for summer 2008

First results

-Neutrino events have been observed in emulsions from PEANUT NUMI test-beam

-CNGS beam run in August 2006 : electronic detectors gave good results

-Cosmic run : brick candidate extraction ; scanning and analysis on the way to validate the full analysis chain

Future

Next CNGS beam run : Autumn 2007

with ~60000-70000 bricks and a beam intensity of 0.43 1019 integrated pot 180 expected events in bricks

14

15

6.9m1.7 m

64 strips/module

Target Tracker

●●Trigger: > 99%● Brick finding : 7080%● Initiate muon tagging

Plastic scintillator strips (AMCRYS-H, 6.7m x 2.6cm x 1cm)readout by Kuraray WLS fibres +Hamamatsu PMT’s (64 channels)

LNGSLNGS

Tracker wall

2 x 256 strips

Reconstructed cosmic track

16

Muon spectrometer

B=

1.5

5 T

base

slabs

coil

8.2 m

M ~ 950t

Drift tubes

12 Fe slabs(5cm thick)

RPC’s

2 cm gaps

identification: > 95% (TT)

p/p < 20% , p < 50 GeV/c

misidentified charge prob. 0.1 0.3%

21 bakelite RPC’s (2.9x1.1m2) / plane

Precision tracker: 6 planes of drift tubes

diameter 38mm, length 8m4 staggered layers / plane,

each layer consisting of 168 tubes

efficiency: 99%space resolution: 300µm

Inner Tracker: 11 planes of RPC’s

17

Reconstruction of micro-tracks (45µm)

2D images 2D images processingprocessing 3D reconstruction of 3D reconstruction of

particle tracksparticle tracks

speed : 20cm²/hour/emulsion side

Résolution (grains) spatial : 0.06 µm Angular : ~ 2 mrad

1 emulsion sheet (2 sides) : 12h scanning - ~5Go

15 scanning laboratories in Europe and Japan

2 emulsion sides (45

m)

1 plastic base (200 m)

16 tomographi16 tomographic c images images = 45µ= 45µmm

300µ

m300

µm

300µm300µm

Field ofField of vue vue

Scanning : emulsion digitisation

18

PEANUT : OPERA test-beam at FERMILAB

Detector placed in the front of the MINOS near detector:

-4 walls of 3*4 OPERA bricks exposed to NUMI beam ( ) in « low energy » configuration (<E>=10GeV, Epeak=3GeV )

-DONUT SFT (scintillators) between each wall

goal : to observe neutrino interactions in OPERA bricks

5 events/brick /day expected bricks exposed ~20days

Exposure time: October 18th 2005 -> Mars 1st 2006

total 160 Bricks made, exposed and developped

Brick piling in dark room

developper

Salerno scanning lab analysis

Neutrino reconstruction in emulsions

SFT-emulsions alignment~500µm spatial resolution

~5mrad angular resolution

19

e oscillation search

mm232322 = 2.5 x 10-3 eV2 23 23 = 45°= 45°

nominal CNGS beam 5 years

90% C.L. limits on sin2(213) and 13 :

Combined fit of ECombined fit of Eee, E, Evisvis, (pt), (pt)missmiss

sinsin22(2(21313)<0.06 )<0.06 13 13 < 7.1º< 7.1º

2.5x10-3 eV2

20

October 27th 2006 shutdown : leaking Drain Connection in the reflector cooling system

Outer conductor (Al)

Titanium joints

Ceramic insulator (500V)

(brazed to the Ti joints)Clamps for vapor tightness

Rupture point – leak!!

Bellows to give (some) flexibility

Reason for rupture :

Alignment errors and geometry too rigid

Vibration

Accident during assembly (?)

Improvements of new design drain connection :

Absorb better any misalignment errors

Water and vapour tightness maintained

Rigourous Quality during assembly

Reparing on the way for Autumn 2007