The ATLAS Experiment: Status Report - Miami · 2008. 12. 24. · ID Commissioning with Cosmic Rays • 220 Millions cosmic events for ATLAS commissioning • ID specific Statistics:

The ATLAS Experiment: Status Report

L. Pontecorvo On behalf the ATLAS Collaboration

12/24/2008 1L. Pontecorvo INFN-Roma

Outline• The ATLAS Experiment at the LHC:• The ATLAS Experiment at the LHC:

– Design & Construction

• Experience with first beams

• Commissioning with Cosmicsg

• Not in the talk: Trigger and DAQ Lucid • Not in the talk: Trigger and DAQ, Lucid (luminosity monitor) etc. 12/24/2008 2L. Pontecorvo INFN-Roma

The ATLAS Collaboration and the LHC complex

CMS general purpose p-pCMS general purpose p-p

TOTEM

LHC 27 km ring

ALICE : ion-ion,p-ion LHCb : ATLAS general

purpose p-pATLAS general purpose p-p

12/24/2008 L. Pontecorvo INFN-Roma 3

pp, B-physics, CP-violation

purpose p-ppurpose p-p

PP Physics at the LHC First beam circulated in First beam circulated in

LHC on the 10th Sept 2008 First Collisions foreseen in

2009 Low luminosity Phase ,

max 10 33cm-2s-1max 10 33cm 2s 1,30 fb-1 in 3 years

H i g h - l u m i n o s i t y P h a s e 1034 m 2s 1~1034 cm-2s-1,~300 fb-1 in 3 years

Experiment trigger to go from 40 MHz bunch crossing to the ~200 Hz to disk for offline 200 Hz to disk for offline analysis


H-> 4 leptons: a benchmark process• Higgs decays in 4 leptons is one of the

b nchm rk pr c ss us d t d si n th benchmark process used to design the detector:– Measure the momentum and energy of electrons gy f

and muons in presence of high background– Discriminate between different particle types– High resolution measurements– Large Acceptance

T ki (| | 2 5 B 2T) Typical structure of a HEP experiment

•• Tracking (||<2.5, B=2T) : -- Si pixels and strips--Transition Radiation Detector (e/ discrim.)

• Calorimetry (||<5) :y-- EM : Pb-LAr-- HAD: Fe/scintillator (central), Cu/W-LAr

(fwd)• Muon Spectrometer (||<2.7) :


p (|| )air-core toroids with muon chambers

The ATLAS detector

4 Superconducting magnets: Central Solenoid 3 Ai T id 3 Air core Toroids

Inner detector Calorimetry Muon Spectrometer

The Superconducting Magnets (1)• Central Solenoid:

– Operated at 7.7 KA

– 2 T uniform field in the 2 T uniform field in the tracking volume (21 m3)

• Toroids:– Barrel and End Caps

jointly operated at 20.4 KAKA

– Stable operations for long periods (weeks)O /Off i hi 5 h


– On/Off within 5 hours

The superconducting Magnets (2)20 43 20 43 20 47 20 47 20 4 20 4 20 5 20 5 20 5 20 5

First excitations of full toroid systems20.43 20.43 kAkA

20.47 20.47 kAkA

20.4 20.4 kAkA

20.5 20.5 kAkA

20.5 20.5 kAkA

15 kA15 kA

10 kA10 kA

20.5 kA Toroid current

R f ll fi ld 22 A l d 25 A 08

7.73 kA Solenoid current

Ramp to full field on 22 Aug, slow dump on 25 Aug 08


3 sub-systems:Inner Detector

• Measure the momentum of ll h d ti l

Silicon pixels : 0.8 108 chanTRT

all charged particles generated in the collisions

3 layers at 5, 10, 13 cm from beam pipeSilicon strips (SCT) :6 106 chan

4 l d l d bl l

SCT• e/ discrimination

4 cylindrical double layers at radius 30, 37, 44, 51 cm

- 2x9 discks in forward regions- hit resolution 17m x 580m February 2006

• Measure interaction and decay vertices (Top and B physics) lepton isolationhit resolution 17m x 580m

Transition Radiation Tracker (TRT) : 4 105 channels Straw tubes operated with Ar – CO2 or Xe-CO2 + O2

February 2006physics), lepton isolation.

Solenoidal B field : 2 TeslaMomentum resolution /pT ~ 5x10-4 pT 0.01

Coverage: ||<2 5


Coverage: ||<2.5 Electron identification: ||<2.0 and 0.5<E<150 GeV

ID installation in ATLASSCT + TRT in place, May 2007


Pixels (+ beam pipe) insertion June 2007

ID Commissioning with Cosmic Rays• 220 Millions cosmic

events for ATLAS commissioning

• ID specific Statistics:

– 7.6 M events with TRT tracks

– 2 M events with SCT 2 M events with SCT tracks

– 423 K events with Pixel hits


hits

SCT and Pixel Commissioning

• Very low noise • Very low noise rate and Dead channels

Pixel hit efficiency

• First results on hit on hit efficiency for Pixel and SCT

Barrel SCT hit efficiency


Inner Detector Alignment (I)

• Pixel alignment: L i t f i li t ff t– Large variety of misalignment effects

– Residual width improved by an order of magnitude from nominal geometry.

– Still some effects to be understood


Inner Detector Alignment (II)• SCT Alignment: g

– Good alignment already achieved for barrel

– Agreement with MC expectations.

– Limited statistics for Limited statistics for End-Cap


TRT CommissioningBubble chamber like picture

Fully commissioned and inside ATLAS data taking since long


TRT is fully operational : ~ 2% problematic channels

TRT results• Alignment and calibration g

of the TRT ongoing: residuals at the level of 210 m

• Transition radiation observed using relativistic rise of cosmic muonsrise of cosmic muons


• Electromagnetic Calorimeter:• Hadron

CalorimetryLAr/Pb electromagnetic Fe/scintillator hadronic TilecalCalorimeter

• barrel, end-cap:Pb LAr Accordeon

Calorimeter

• Barrel: Iron-Tile (104 h l )

g

HEC

Pb-LAr Accordeon

• ~10%/√E energy l ti /

(104 channels)

• EC/Fwd: Cu/W-LAr (~2*104

EM FCAL

resolution e/γ

• 180’000 channels:

LAr (~2 104

channels)

• /E ~ 50%/E 3 longitudinal samplings + presampler

/E 50%/E 0.03 pion (10 )

• /E ~ 100%/E LA /C h d i0.1 (Forward)

~ 12 m long, 4.3 m radiusLAr/Cu hadronic

LAr/W forward

Trigger for e/γ jets missing E12/24/2008 L. Pontecorvo INFN-Roma 17

Trigger for e/γ , jets, missing ET

The Barrel Calorimeter

12/24/2008 L. Pontecorvo INFN-Roma 18October 2004

LAR Calorimeter: Hardware statusSince May 2008

•LAR calorimeters fully operational:

•All Channels read-out

•DAQ and DCS smoothly •DAQ and DCS smoothly running

l % f •Only ~ 1% of recoverable dead channelschannels

• Still some problems with LV PS and Front End Boards to be


t m pr m w th LV an Fr nt En ar t addressed during the shut down.

LAR Calorimeter: Commissioning with Cosmics

• Check uniformity of LAR • Check uniformity of LAR cell response with cosmic muons: Muon signal in LAR: 250 MeV

– With collected statistics aim at 1% precisionp

• Detailed study of pulse Detailed study of pulse shape (32 samples):

– very good understanding of very good understanding of the full electronic chain and of the geometry of the cells.

Pulse shape measured with 32 samples


Tile Calorimeter: Hardware Status

Full calorimeter up and running, integrated in DAQ and DCS~0.2% dead (isolated) cells, and 2 of 256 sectors off


. a ( so at ) c s, an of 56 s ctors off power supply problem will be repaired during shutdownwith access

Tile Calorimeter performances

M n n L ss • Muon energy Loss in Tilecal

• Cell uniformity measured with measured with horizontal muons


The Muon SpectrometerTrigger on high Pt muons in

End cap: 1 < | | < 2.7Tracking with MDTs & CSCs Triggering with TGCs up to | | =2.4

gg gpresence of high background

Resistive Plate Chambers (RPC)Thin Gap Chambers (TGC)

Barrel: | | < 1.0Tracking with MDTs T i i ith RPC

Thin Gap Chambers (TGC)Measure the muon momentum with high precision

Monitored Drift Tubes (MDT)Triggering with RPCsMonitored Drift Tubes (MDT)Cathode Strip Chambers (CSC)

| | | 2 7| 2 7Acceptance : |Acceptance : | | < 2.7| < 2.7Pt Resolution: Pt Resolution:

~10% @ 1 TeV/~10% @ 1 TeV/cc


10% @ 1 TeV/10% @ 1 TeV/cc< 3 % P< 3 % Ptt<250 GeV/<250 GeV/cc

The Muon End CapEnd-Cap Toroid

Bi Wh lBarrel station

p(parked off-beamBig Wheel

Small Wheel

TGC BIG WHEEL

Beam Line

1/8 Barrel Toroid


Muon Trigger concept

• Three planes of trigger gg

detectors both in Barrel and

End-CapEnd ap

• Interaction point and detector pivot plane define position of the coincidence window on the second and third detector plane coincidence window on the second and third detector plane.

• Trigger selection performed both in the bending and non-bending plane to reduce fake trigger rate due to the high background level.

• Multiple trigger thresholds : Low pt (6 10 Gev/c) and High pt (11 40


• Multiple trigger thresholds : Low pt (6-10 Gev/c) and High pt (11-40 Gev/c )

Muon Spectrometer: Hardware StatusCSC

99 5% of channel are ready MDT hardware status99.5% of channel are readyrate limitation in read-out being worked on

MDT98 5% f h ls ti98.5% of channels activeRemaining HV and Gas problems are being fixed during shut down

Optical Alignmentp g99.7% operational in barrel99% operational in end-caps

RPC92% of Trigger towers cabled92% of Trigger towers cabledCommissioning still ongoing for detector and Trigger/read-out electronicsFine tuning of trigger timing in progress

TGCTGC99.8% of chambers ready for operationExcellent trigger timing achieved3 chambers damaged by over-pressure 3 chambers damaged by over pressure being exchanged


Muon Spectrometer performances: MDT• Tube efficiency:

– Comparable to Test Beam measurements

Hit t id lEfficiency per tube • Hit on segment residuals:

– Better than 100 mOptical Alignment:

per tube ~0.95

• Optical Alignment:– Barrel 250 m to be improved– End Cap 40 m: OKp

After align

Segment residualsBefore align

After align


Muon Spectrometer performances: TGC

• High operation • High operation efficiency at nominal voltagenominal voltage

• Excellent timing:• All events read

out in the proper bunch


Muon Spectrometer performances:RPCCosmic maps of the

ATLAS elevators:neglected by cosmics generatorp

shafts– RPC tracks

extrapolated to the extrapolated to the surface (100 mt) show the 2 ATLAS shafts and the 2 ATLAS lifts

ATLAS Shaftsmain arrival for muons

and the 2 ATLAS lifts

d l – Very good Correlation between RPC and MDT


Combined performance with Cosmics• Difference of

momentum measured in MS and ID compatible with expectations

• A nice cosmic event seen by all the ATLAS systems


ATLAS systems

First Beams in Atlas

• On September • On September 10th the first beam interactions

d d were recorded in ATLAS

• Big excitement in the counting room after so many years of preparationpreparation


First Splash Event The very first beam-h ry f rst am

splashevent from the LHC in

ATLASon 10:19, 10th

September 2008

L. Pontecorvo INFN-Roma 32

A Beam haloBeam Halo event with many reconstructed curved tracks


Some observations with first beam10 September

10 September

10 September

12 September12 September

• Trigger timing: • Energy in Calorimeters from b l h

gg g– In few days most triggers

were timed in12/24/2008 L. Pontecorvo INFN-Roma 34

beam splashes:• Peaks due to presence of

EC Toroid

Conclusions

• All the components of the ATLAS • All the components of the ATLAS detector are working fine

Commissioning with the large amount of – Commissioning with the large amount of cosmic data is going on.

– The understanding of the detector g f(efficiency, alignment, resolution, etc.) is improving steadily Th ATLAS d t t READY f th – The ATLAS detector was READY for the first beamDuring the shut down we are consolidating – During the shut down we are consolidating this very good situation to get to the first collisions with an even BETTER detector.


Spares


Higgs production and branching ratiosK~2.0

K~1 2

• Productioncrosssections

K~1.2

K~1 4

andK-factors

K~1.4

K~1 1 DK~1.1

Typical uncertainties

• Decaybranchingratios atNLOTypical uncertainties

• gg 10-20 % (NNLO)• VBF ~ 5% (NLO)• WH,ZH ~< 5% (NNLO)

ttH 10 20 % (NLO)

NLOFew %accuracy


• ttH 10-20 % (NLO)

Documents

The ATLAS Experiment: Status Report - Miami · 2008. 12. 24. · ID Commissioning with Cosmic Rays • 220 Millions cosmic events for ATLAS commissioning • ID specific Statistics: