ichep 2004, beijing h. pessard/ opera - 1 the opera experiment cngs long-baseline program in europe ...
TRANSCRIPT
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)
ICHEP 2004, Beijing H. Pessard/ OPERA - 2
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)
ICHEP 2004, Beijing H. Pessard/ OPERA - 3
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 4
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 5
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.
ICHEP 2004, Beijing H. Pessard/ OPERA - 6
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 7
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 8
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 9
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:
ICHEP 2004, Beijing H. Pessard/ OPERA - 11
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 12
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 13
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)
ICHEP 2004, Beijing H. Pessard/ OPERA - 14
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 15
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 16
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 17
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 18
.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
ICHEP 2004, Beijing H. Pessard/ OPERA - 19
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 20
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)
ICHEP 2004, Beijing H. Pessard/ OPERA - 21
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
ICHEP 2004, Beijing H. Pessard/ OPERA - 22
- 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