ICHEP 2004, Beijing H. Pessard/ OPERA - 1 The OPERA experiment CNGS long-baseline program in Europe ...

ICHEP 2004, Beijing H. Pessard/ OPERA - 1

The OPERA experiment

CNGS long-baseline program in Europe Search for appearance in a beam:

prove nature of atmospheric oscillation,measure m2 Search for e oscillations (measure 13)

OPERA Collaboration:Belgium, China, Croatia, France, Germany, Israel, Italy, Japan, Korea, Russia, Switzerland, Turkey

H. Pessard (LAPP Annecy France), for the OPERA Collaboration

Hall C

Hall BICARUS

Gran Sasso underground lab

OPERA

CERN s

Direct observation of decay topology using nuclear photographic emulsions

35 groups, ~ 170 physicists

(CNGS1)


CERN Neutrinos to Gran Sasso

732 Km11 Km

CNGS beam optimized for appearance:

E = 17 GeV

At 732 km in OPERA: 6200 CC+NC /yearexpected + 27 CC/year (m2= 2.4 10-3 eV2)

400 GeV proton beam4.5 x 1019 protons/year (7.6 x 1019 dedicated mode)200 days/year, = 55%

(ee) 0.85 %

2.1 %

prompt negligible

CNGS horns(Orsay)


21

1

23

steel decay pipe installed18 mm thick, 4.5 m Ø, + 50 cm of concreteVacuum leak test on full 998 m tube OK

CNGS beamconstruction

at CERNon schedule

First beam to Gran Sasso in May 2006

Intensity upgrade (x1.5) under study

3


OPERA appearance detection

CC events: detection of the decay kink

Pb

Emulsion layers

1 mm

e,

p,n,,K...

,e,

BR 17.4 % h(n)49.5 %

ee17.8 %

(n)15.0 %

Based on the Emulsion Cloud Chamber (ECC) technique: emulsions for tracking, high Z plates as target

ECC technique used in discovery (DONUT-

2000)

Target mass ~1.8 Kton

+ film alignment 1 m

high modularity

Basic unit: ECC “Brick”56 lead plates

57 emulsion films

8.6kg

10 X0

10.2 x 12.7 x 7.5 cm

Film base


OPERA bricks and electronic detectors

Trigger and localisation of interaction

Spectrometer sections:22 RPC planes in dipolar magnet6 sections of Precision Trackers

1775 tons target:200 000 bricks

ECC bricks alone can provide: - vertex and decay kink reconstruction- momentum measurement by MCS- / separation at low E by dE/dx- energy measurement of em showers,identification of electrons

2 Super-Modules

~ 9m

TEST experiment at CERN PS1 mm

5 cm

Target sections:31 vertical “walls” of bricks31 scintillation X-Y Target Tracker planes

Muon ID, momentum, charge meas.


OPERA hybrid detector operation

Pb/Em. brick

8 cm

- daily brick extraction (~30 bricks/day) by robot- cosmic ray exposure- film development

8 m

Target Trackers

Pb/Em. target

Pb 1 mm

Basic “cell”

Emulsion

Spectrometer trackers

Electronic Data Acquisition in Gran Sasso - interaction tagging, brick selection- event measurement

Scanning stations in Japan and Europe - vertex location- decay detection- event full Data Acquisition: e/ ID, MCS, / separation, kinematics

3

2

1


OPERA search for , topologies(1) Pick up all tracks from the interaction on the most downward film

5x5cm2 for CC a film full surface for NC

(2) Scan back picked up tracks (3) confirm interaction vertex; tracks stopped in 2 consecutive films (4) search for kink candidates(5) fully measure candidate events

I.P.

Short decays

Pb

Scanning

power

Pb

Long decays

Emulsion layers (not to scale)

Plastic base

kink

kink > 20 mrad

(kink ) ~ 3 mrad

Impact Parameter > 5 to 20 m (along Pb plate) (I.P.) = 0.3 to 0.6 m


Status of OPERA construction

Brick Manipulator System

Spectrometer sections:installation started May 2003

SM1 magnet complete June 2004

Target planes support

SM2 magnet complete in April 2005

Target sections:installation starts September 2004


OPERA magnets

June 2004 Magnet 1: all 22 gaps filled with RPC

slabs

base

B= 1.55 T

coil

5 cm Fe slabs x 12 x 2Total magnet weight 1000 tons

pp20-25%, charge mis-Id 0.3%ID > 95% (Target Tracker + PT)

May 2004

With Precision Tracker:


OPERA in construction: summer 2004

July 2004


Spectrometer RPC and Precision TrackerNov 2003: 1st plane of RPC installed

May 2004: SM 1 fully equipped 462 RPC, 1540 m2 (22 walls) 1160 RPC produced, Q-acceptance 70%•Mechanical test, gas tightness •HV, electrical tests in Ar•Noise, Efficiency with cosmicsGas and HV tests repeated in Hall C

prototype module

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

Installation: spring 2005

Drift tubes Tracker

4 layers, 8 m tubes 38 mm Ø, 50 m wireSimplified version of ATLAS drift tubes

For 25% P/P :x ~ 0.5 mm, high multi-hit

8 m


Target Tracker and brick walls

Construction of TT modules (64 strips) in progress: 8 modules/week

X and Y planes, 6000m2 in total- Scintillator strips (6.86m x 2.6cm x1cm):AMCRYS-H (Kharkov) above 5 p.e. specifs.- Kuraray WLS fibers1000 MaPMT Hamamatsu 64-channels- Dedicated Front End electronics: gain correction auto-triggerable, threshold @ 1/5 p.e.- Ethernet DAQ cards

Brick wall full height prototype (6.7m)

Well above 5 p.e. /

readout end

Target installation at LNGS: September 2004 - December 2005


ECC brick components: emulsion films, lead

Film production started April 2003 (~150 000 m2)

• films made by Fuji Film Co. (joint R&D with Nagoya Univ.) 20% of 13 M films producedFilm refreshing (erasure of CR tracks): facility in

Tono Mine, Japan (700 bricks/day) being commissioned

Film delivery at GS October 2004, CS May 2005

Refreshing parameters

Humidity : > 95%

Temperature : 30 ºC

Time : ~ 3 days

Pb plates1mm thick 10m- ready for prototype production at Goslar Co.- Pb/Ag/Al-Sn to replace Pb/Ca (compatibility with emulsions)


Brick assembly

BAM contracted Jan 2004 with Tecno-Cut (Swiss-Italian Co)• Delivery at LNGS: April 2005Brick assembly: Sep 2005, 1 yearFilling SM1 March 2006 SM2 September 2006

Mechanical packaging adopted (long term tests): less fragile than vacuum packaging pressure produced by springs and fiberglass scotch tape light tightness with Al adhesive tape

Brick Assembly Machine (BAM)2 bricks/min200 000 bricks

Packaging

Piling stations

40 m hall A

/ hall B

by-pass

Lead handling


Brick manipulator system

Installation at LNGS: April 2005, Start detector brick filling: Sep. 2005

Porticoeson each side of detector,to place platform in front of brick rowPlatforms

horizontal positioning brick pushing in wall brick retrieving vehicle

Under construction and tests

Storage carrousel


Automatic scanning R&D in Nagoya and Europe

S-UTS prototype at Nagoya

Dedicated hardwareHard coded algorithms

European station

Commercial hardwareSoftware algorithms

~ 2mradx ~ 0.3 m

500 fps CMOS camera

Bari, Bern, Bologna, Lyon, Napoli, Neuchâtel, Roma, Salerno

Scanning lab to be installed @LNGS

• European system: recent version working at 20 cm2/hr/side (15 to install)• S-UTS system expected to reach similar performances (under completion)

Fast CCD camera (3 k frames/sec) Continuous movement of the X-Y stage


Channels considered at CNGS approval time (1999)

e (DIS+QE, long) (DIS+QE, long)

Overall efficiency

DIS long QE long DIS short Overall (weighted sum)

e 2.7 2.3 1.3 3.4

2.4 2.5 0.7 2.8 h 2.8 3.5 - 2.9

Total 8.0 8.3 1.3 9.1 %

Efficiency increases under study:• Brick finding efficiency improved analysis and strategy (+10%)• BFE increase (?) with changeable sheet on the back side of the brick• channel 3 prongs (1.0% additional efficiency, including BR 15%)

*BR

OPERA detection efficiencies

Efficiencies include:BR, long/short, BFE,kink + kinematics cut, Id and connection


.707 .516.278 .276.219 .123.210 .117Total per channel

.209 .209.116 .116.093 .093Hadronic background

.116 .023.116 .023Large angle μ scattering

.382 .284.162 .160 .010 .007 .210 .117Charm background

Total h e 5 years, nominal beamin red: possible BKGD reduction

Charm background :Being re-evaluated using new CHORUS data: charm production increase by 40% (larger c production), charm semileptonic BR down by 20%. In additionπ/μ Id by dE/dx would reduce the charm background by 40%

being tested at KEK and this autumn at PSI (pure beam of π or μ stop)Large angle μ scattering :

Upper limit from past measurements used so far Calculations including nuclear form factors give a factor 5 less

BKGD reduction will be checked in 2004 in X5 beam with Si detectorsHadronic background :

Estimates based on Fluka standalone : 50% uncertainty. Error down to ~15%, improved sensitivity with extensive comparison of FLUKA with CHORUS data

Expected number of background events


Number of events in 5 years @ 4.5 x1019 pot / year

1.0 (1.5)19.9 (29.9)

12.8 (19.2)

8.0 (12.1)BFE improved by 10%+ 3 prong decay

0.7 (1.1)16.4 (24.6)

10.5 (15.8)

6.6 (10.0)OPERA1.775 tons

0.8 (1.2)With possible BKGD 30% reduction

BKGDsignal

3.0x 10-3 eV2

signal

2.4 x 10-3 eV2

signal

1.9 x 10-3 eV2

(...): with CNGS beam upgrade (x1.5)

sensitivity


SK 90% CL(L/E analysis)

Opera with beam x2

Opera with beam x3

Opera nominal

Opera with beam x1.5, no BKGD reduction

Opera nominal beam and half background

Opera with beam x1.5, possible improvementsand BKGD reduction

Sensitivity versus Beam Intensity

(~equivalent)


185.21.04.63.05º

0.0827.0x10-40.34x10-40.0320.31Efficiency

eCC beam

NCCCesignal13

185.21.04.65.87º

185.21.04.57.48º

185.21.04.59.39º

Expected signal and backgrounds assuming 5 years data taking,nominal CNGS beam and m2

23=2.5x10-3 eV2, sin2223=1

simultaneous use of Evisible, Eelectron and missing Pt

7.1º 6.4º

0.06 0.05 (beam x1.5)

13 limit 90% CL sin2213 limit Sensitivity to 13 has a dependence on CP complementary to T2K

e sensitivity


- OPERA is looking for oscillations ( appearance)

and e oscillations (measurement of ) as part of the European long baseline Neutrino program

- The OPERA collaboration since the approval in 2000 accomplished great progress towards the realisation of this large and delicate detector

- Work is going on to improve the sensitivity by reducing the background and increasing the efficiency. The expected increase of the beam intensity will have a similar effect to secure the appearance observation.

- The CNGS beam and the OPERA experiment will start in 2006

Conclusions

ICHEP 2004, Beijing H. Pessard/ OPERA - 1 The OPERA experiment CNGS long-baseline program in Europe ...

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