The CMS Construction

(CMS) Design Criteria

Very good muon identification and momentum measurementTrigger efficiently and measure sign of TeV muons dp/p < 10%

High energy resolution electromagnetic calorimetry~ 0.5% @ ET ~ 50 GeV

Powerful inner tracking systemsMomentum resolution a factor 10 better than at LEP

Hermetic calorimetryGood missing ET resolution

(Affordable detector)

Transparency from the early 90’s

Experimental Challenge

High Interaction Rate

pp interaction rate 1 billion interactions/sData can be recorded for only ~102 out of 40 million crossings/secLevel-1 trigger decision takes ~2-3 s electronics need to store data locally (pipelining)

Large Particle Multiplicity

~ <20> superposed events in each crossing~ 1000 tracks stream into the detector every 25 nsneed highly granular detectors with good time resolution for low occupancy

large number of channels (~ 100 M ch)

High Radiation Levels radiation hard (tolerant) detectors and electronics

LHC Detectors (especially ATLAS, CMS) are radically different from the ones from the previous generations

The CMS Detector

The CMS Collaboration (2007)

2310 Scientific Authors 38 Countries 175 Institutions

CERN

France

Italy

UK

Switzerland

USA

Austria

Finland

GreeceHungary

Belgium

Poland

Portugal

SpainPakistan

Georgia

Armenia

Ukraine

Uzbekistan

CyprusCroatia

China, PR

Turkey

Belarus

EstoniaIndia

Germany

Korea

Russia

Bulgaria

China (Taiwan)

Iran

Serbia

New-Zealand

Brazil

Ireland

1084

503

723

2310

Member States

Non-Member States

Total

USA

# Scientific Authors

59

49

175

Member States

Total

USA

67Non-Member States

Number ofLaboratories

Associated Institutes

Number of ScientistsNumber of Laboratories

629

Oct. 3rd 2007/gm

Mexico ColombiaLithuania

Exploded View of CMS

Minus SidePlus Side

Assembly of Iron Yoke

2003

Assembly of the Coil

Assembly of the Coil

Coil: 230 tonsOuter vacuum tank: 13 m long SS tube, =7.6 m

Sept 05Sept 05

Surface Hall: Barrel Muons

Lowering of Heavy Elements

YE+1 (Jan’07)

Lowering of Heavy Elements

Feb 2007

Insertion of Barrel ECAL

Jul’07

Completion of Services on YB0

Nov. ‘07

Lowering of Tracker

Dic. ‘07

Tracker Insertion

Dic. ‘07

Tracker in CMS

Dic. ‘07

Extreme engineering: 4T, big dimensions & large magnetic deformation

0.0

2.0

4.0

6.0

8.0

10.0

12.0

10 100 1000 10000

E/M

(kJ

/kg)

Stored Energy (MJ)

CMSSDC-model

ATLAS -sol.

ALEPH

DELPHI

H1CDF

VENUS

ZEUS

TOPAZCLEO2

ATLAS Barrel

ATLAS End-caps

The CMS SC Solenoid

Solenoid composed by 5 modules

(CB-2, CB-1, CB0, CB+1, CB+2)

5 modules 6900 mm ; L 2500 mm ; W= 50 t

I = 20kA

Design Goal: Measure 1 TeV/c muons with < 10% resolution

Winding of the Coil

Specific winding technology developed by INFN Genova in collaboration with Ansaldo Superconduttori

Winding

Test of the Magnet (2006)

24 July28 August

19 kA, 4 Tesla!

2 days stable operation at 3.8 T

Magnet Current Cycles achieved during August

Tracking at LHC

Fluence over 10 years of

LHC Operation

Need factor 10 better momentum resolution than at LEP1000 particles emerging every crossing (25ns)

Layout of CMS Tracking

Si pixels surrounded by silicon strip detectors

Pixels: ~ 1 m2 of silicon sensors, 65 M pixels, 100x150 m2 , r = 4, 7, 11 cmSi strips : 223 m2 of silicon sensors, 10 M strips, 10 pts, r = 20 – 120 cm

120 cm

TOB

TIDTIB

TEC

Pix300 cm

CMS

The CMS Tracker

Pixel Silicon Strip Tracker

Largest Silicon Strip Detector ever built:

~200m2 of silicon,

instrumented volume ~24m3

TIB (4 layers ) TID (3 disks, 3 rings ) TOB (6 layers) TEC (9 disks, 7 rings )

Si Modules and Electronics Chain

Si Sensors

75k chips using 0.25m technology

Ride on technology wave

System Components

Module Sensor + FE Hybrid

chip: APV25 (128 strips) - analog Optical converter (AOH)

one laser/fiber = 256 strips Controls/Clock/Trigger

Control chip (CCU) I2C protocol with modules rings of CCUs

Digital optical converted (DOH) optical link to VME controller (FEC)

Controls

Hybrid+AOH

String

System Components

DOM (Firenze)DOM (Firenze)

Mother cable (Bari)Mother cable (Bari)

CCUM (Cern)CCUM (Cern)

AOH (Perugia)AOH (Perugia)Modules (all)Modules (all)

The Start of the TIB Integration

The first string

Apr. ‘05

Si Tracker

TIB TEC

Si Tracker

Si Tracker

Tracker Readied for Installation

Dead channels ~ 0.5 ‰ stable in timeNoisy channels ~ 0.5 % stable in time

Lead Tungstate ECAL Design Goal: Measure the energies of photons from a decay of

the Higgs boson to precision of ≤ 0.5%CMS chose scintillating crystals

1972

1985

1989

1986

1990

1999

2008

m3

Crystal Ball

672 NaI(Tl)

Cleo II

7800 CsI(Tl)

L3

12000 BGO

Crystal Barrel

1380 CsI(Tl) TAPS

600 BaF2

KTeV

3100 CsI

Babar

6580 CsI(Tl)

Belle8816 CsI(Tl)

Alice

17920 PWO

CMS75000 PWO

From Crystal Ball

5

10

To CMS

P. Lecoq

CMS Requests and PWO

1995 1998

T dependent: -2%/°C

To comply with LHC and CMSTo comply with LHC and CMSconditions ECAL must be:conditions ECAL must be:• fastfast• compactcompact• highly segmented highly segmented • radiation resistantradiation resistant

Very low light outputVery effective in highenergy containment

2

ECAL layout

barrelbarrelSuper ModuleSuper Module(1700 crystals)(1700 crystals)

endcapendcapsupercystalssupercystals(5x5 crystals)(5x5 crystals)

Pb/Si preshowerPb/Si preshower

barrel cystalsbarrel cystals

EndCap “Dee”EndCap “Dee”3662 crystals3662 crystals

Barrel: Barrel: ||| < 1.48| < 1.48

36 Super Modules36 Super Modules61200 crystals (61200 crystals (2x2x23cm2x2x23cm33))

EndCaps: EndCaps: 1.48 < |1.48 < || < 3.0| < 3.0

4 Dees4 Dees14648 crystals 14648 crystals (3x3x22cm(3x3x22cm33))

PWO: PbWO4

about 10 m3, 90 t

Choice of the Photodetector

20

40mdeff ~6m

Avalanche photodiodes (APD)

Two 5x5 mm2 APDs/crystal- Gain: 50 QE: ~75% @ peak= 420 nm- Temperature dependence: -2.4%/OC- Gain dependence on bias V: 3%/V

PWO Production

BARREL ingot

45000

47000

49000

51000

53000

55000

57000

59000

61000

63000

Dec-05 Mar-06 Jul-06 Oct-06 Jan-07 Apr-07

Del

iver

ed B

arre

l cr

ysta

ls

BARREL CRYSTALS ~ 1150 xl/m

EE INGOT

ENDCAPS ingots

EB Construction: Regional Centers

CERN Lab.27 EP-CMA

Casaccia

&

Assembly and test of modules in RC: ENDED in March 2007

Submodule 2x5 crystals

Submodule 2x5 crystals

Module400 crystals

INFN/ENEA Regional CenterCheck crystals in Rome RC

Glue subunits and check APD gain

The first submodule!The first module!

Y 2002

EB Construction: Super Modules

Supermodule1700 crytsalsSupermodule1700 crytsals

Cooling and electronics integration: completion by May 2007

Dead channels: 19/61200

ECAL PerformanceResponse to high energy electrons

Temperature Stability: ≤ 0.1 °CLight response stability: ≤ 0.1%

0.5%

ECAL: Cosmics Signal in CMS

Layout of CMS Muon System

250 DTs 468 CSCs 480 RPCs

Spatial resolution: Single cell 200 mChamber 100 m

Muon System: Drift Tubes

MylarMylar

Electrode Electrode StripStrip

Wire

42mm

13 mm

Legnaro Assembly Hall

Torino Assembly Hall

Assembly of 250 DT chambers:70 Aachen, 70 Madrid70 Padova, 40 Torino• 1 layer = 70 wires• 27 gluing operations/chamber• 1 gluing operation = 1 dayPrecision of 100 m over 5-10 m2

DT Chambers Assembly

CERN ISR

First installation Aug.03

Salvato

Peghin

First installation test Aug. 2002

Muon System: Start of Installation

ISTALLATION OF THE LAST OF THE 250 DT CHAMBERS IN THE CAVERN. IN WHEEL YB0 26 Oct. 2007

Muon System Completed

S11

S12

17Hz

S01

3Hz

10Hz

15HzS0330Hz

Muon System: YB0 DTs in Operation!

Gas mixture95.5 C95.5 C22HH22FF4 4

3.5 iC3.5 iC44HH1010 0.3 SF0.3 SF66

+ RH 50%+ RH 50%

Main Unit of a RPC: Single Gap (SG)

Two SG coupled with readout plane in between

•Bakelite thickness: 2 mm•Bakelite bulk resistivity : 2-6 1010 cm• Gas Gap width: 2 mm•Operating voltage: 9.2-9.8 kV

Main characteristics of the RPCs used in CMS:

Muon System: Resistive Plate Chambers

RB4 120 chambers (2 double gaps/chamber)

RB3 120 chambers (2 double gaps/chamber)

RB2 60 chambers (2 double gaps/chamber) + 60 chambers (3 double gaps/chamber)

RB1 120 chambers (2 double gaps/chamber)

Forward UP

Forward Down

Backward UP

Backward Down

DoubleDouble

Gap Gap DGDG

DoubleDouble

Gap Gap DGDG

RPC chamber layout

480 RPCs coupled with DTs and inserted into the iron return yoke of the magnet

RPC Performance

Efficiency

Counting rate

All parameters are compatible with the results obtained during the production tests

Cluster size

RPC: First Events in CMS

First Closure of the CMS Experiment (2006)

Magnet Test & Cosmic Challenge (MTCC)

HCAL

Magnet

Tracker

Muon chambers

ECAL

Run 2605 / Event 3981 / B 3.8 T / 27.08.06

Cosmics in the Tracker (Bat 186)

•The Quality of the CMS Tracker is Excellent: • Dead or Noisy Strips < 3 / 1000

• Signal: Noise > 25:1 in Peak Readout Mode

• Enormous experience gained in operating the Tracker at TIF

Normal Strips 99.852 % (241 313 Strips)

Dead Strips 0.116 % (275 Strips)

Noisy Strips 0.032 % (76 Strips)

Example of Performance

A cosmic at -15°CValidated clusters shown

Performance of CMS: Overview

Tracking

HCAL

b-tagging