1. LHC SPS PS

2. 46 m 22 m A Toroidal LHC ApparatuS - ATLAS As large as the CERN main bulding

3. Inner detector: Performances :  Rapidity coverage |  | < 2.5  Reconstruction of isolated leptons  p T / p T ~0.1 p T (TeV)  Track reconstruction efficiency isolated tracks  > 95% within jets  > 90%  Low material budget for tracker and ECAL performances  Lifetime 10 LHC years (10 7 s/yr) 3 years at low luminosity (10 33 cm -2 s -1 ) 7 years at high luminosity (10 34 cm -2 s -1 )  (R  )= 16  m  (z) = 580  m  (R  )= 16  m  (R) = 580  m Barrel End-cap

4. Higgs in SM and in MSSM Supersymmetric particles B physics (CP violation,...) Exotic physics Requires a good tracking performance: Secondary vertices Impact parameters resolution Track isolation Measurement of high momentum particles Physics requirements TDR : ”…The guiding principle in optimizing the ATLAS experiment has been maximizing the discovery potential for new physics…” B-hadrons: c  ~ 460  m Secondary Vertex reconstruction Daughter impact parameter Primary vertex : prompt tracks in the event Secondary vertex:  (R  )= 16  m  (z) = 580  m  (R  )= 16  m  (R) = 580  m Barrel End-cap

5. ~63 m 2 of silicon ~6 million readout channels ~15,000 silicon wafers ~4000 modules 9disks 5.6 m 1.04 m 1.53 m 4 barrel layers

6. Heat spread materials: TPG Strip length Precise Assembly Location Pitch ~80  m Stereo ~40 mrad Mech. Stability Perm. def. < 5  m Elastic def. < 50  m >95% Eff. Noise occ. ~5  10 -4  R  ~ 19  m  zR ~580  m No align. Inside module Op. Threshold S/N V depletion > 350 V T op = -7 o C Thermal runaway 2  10 14 n eq /cm 2 hadron fluence (10 years) 10 Mrad 40 MHz bunch frequency 100 kHz L1 trigger freq. 3  s T1 latency Temperature cycles (-15 o C 25 o C ) Low mass: <0.4X o at outer rad. of SCT What a module has to stand: What we require :

7. Radiation Hardness Radiation Dose = 2 10 14 n eq /cm 2 10 MRad Damage of the surface: - creation of charge carriers in silicon oxide - change of interstrip capacitance -> noise Damage in the bulk material: - Displacement of Si atoms from lattice sites - Change in effective doping (type inversion) - Deterioration of charge collection efficiency - Increase of depletion voltage ~ 350 V - Increase in leakage current  fluence  Before Irradiation After Irradation

8. Control logic Data Compression logic DMILL BiCMOS process 6.6x8.4 mm 2 132 cells pipeline  3.3  s latency for L1 Trigger Readout Chips Analog Front End Binary readout: the charge collected by the strips is amplified and then goes through a disciminator. If the charge is above a certain threshold, commonly 1 fC, the electronics produces a logic-level 1 signal.

9. 180GeV/c pions Spot Size ~1cm TestBeam (CERN SPS-H8 beam line) SCT tracking specifications require 99% efficiency and noise occupancy below 5.10 -4. Before Irradiation After Irradiation TRACKING STUDY

10. Radiation damage to the electronics: Threshold voltages of MOS transistors changed -> offset spread Degraded gain Noise increase 50 mV/fC 1500 ENC 30 mV/fC 2000 ENC Before Irradiation After Irradiation

11. Detectors temperature at –7°C (beneficial annealing) Runaway point > 240  W/mm 2 at 0°C Leakage current Power dissipation Temperature The leakage current is temperature dependend I leak ~ T 2 exp (-Eg/2kT) Power dissipated 7-10 W/module TOTAL 30KW Thermal Runaway Thermal Performances

12. References TDR: http://atlas.web.cern.ch/Atlas/ /internal/tdr.html Thermal Performance ATL-INDET-2002-010 Test Beam ATL-INDET-2002-025 Electrical Performance ATL-COM-INDET-2003-008 Mauro Donegà Département de Physique Nucleaire et Corpuscolaire Université de Genève Thermal simulations and measurements