13. Recirculation Concept - Cyclotron Radio frequency alternating voltage Hollow metal drift tubes time t =0 time t =½ RF period D-shaped RF cavities Orbit radius increases with momentum Orbital Frequency independent of momentum Particle motion and RF in phase Lawrence: 4” – 80 keV 11” - 1.2 MeV

14. Constant revolution frequency momentum radius magnetic field Equilibrium Orbit Magnetic Force Centrifugal Force =

15. Synchrotron Ring Schematic Focusing magnets Vacuum tube Accelerating Voltage Bending magnets During acceleration, momentum increases Increase magnetic field during acceleration. Constant orbital radius

16. Colliding Beam Synchrotron

17. Constant revolution frequency Equilibrium Orbit momentum radius magnetic field

18. CERN Seen from the Air Tunnels of CERN accelerator complex superimposed on a map of Geneva. Accelerator is 50 m underground 25 km in circumference

19. Alors, c’est fini! Et maintenant?

20. Interaction of Charged Particles with Matter All particle detectors ultimately use interaction of electric charge with matter –Track Chambers –Calorimeters –Even Neutral particle detectors Ionization Multiple Scattering Cerenkov Transition Radiation Electron’s small mass - radiation

21. How we did it in the past – Bubble Chamber Magnet

22. You could actually see what was going on 1960s computer

23. Bubble Chamber – ionization trails in superheated liquid hydrogen Electron knocked out of atom Spirals in magnetic field

28. R.S. Orr 2009 TRIUMF Summer Institute  Layers of Detector Systems around Collision Point Generic Detector

29. R.S. Orr 2009 TRIUMF Summer Institute Generic Detector  Different Particles detected by different techniques.  Tracks of Ionization – Tracking Detectors  Showers of Secondary particles – Calorimeters

30. R.S. Orr 2009 TRIUMF Summer Institute Generic Detector  Different Particles detected by different techniques.  Tracks of Ionization – Tracking Detectors  Showers of Secondary particles – Calorimeters

32. R.S. Orr 2009 TRIUMF Summer Institute  Layers of Detector Systems around Collision Point Computer Display of Event

33. R.S. Orr 2009 TRIUMF Summer Institute ATLAS Detector  Different Particles detected by different techniques.  Tracks of Ionization – Tracking Detectors  Showers of Secondary particles – Calorimeters

34. R.S. Orr 2009 TRIUMF Summer Institute ATLAS Wedge  Different Particles detected by different techniques.  Tracks of Ionization – Tracking Detectors  Showers of Secondary particles – Calorimeters

35. R.S. Orr 2009 TRIUMF Summer Institute Wire Chamber

36. R.S. Orr 2009 TRIUMF Summer Institute 3 stages in signal generation 1) Ionization by track passing through cell 2) Ionization drifts in E field time 3) In high E field region near wire, primary ionization electrons gain enough energy to start ionizing the gas - Avalanche - More charges - Charge amplification - Noise free amplifier microvolt signal if no amplification

37. R.S. Orr 2009 TRIUMF Summer Institute Generic Detector

38. R.S. Orr 2009 TRIUMF Summer Institute Generic Detector

39. R.S. Orr 2009 TRIUMF Summer Institute Simple Drift Chamber

40. TRT endcap A+B TRT endcap C TRT barrel SCT barrel SCT endcap Pixels The ATLAS Inner Detector

41. R.S. Orr 2009 TRIUMF Summer Institute ATLAS Tracker

42. Inner Detector (ID) The Inner Detector (ID) comprises four sub-systems: Pixels (0.8 10 8 channels) Silicon Tracker (SCT) (6 10 6 channels) Transition Radiation Tracker (TRT) (4 10 5 channels

43. R.S. Orr 2009 TRIUMF Summer Institute ATLAS Wedge  Different Particles detected by different techniques.  Tracks of Ionization – Tracking Detectors  Showers of Secondary particles – Calorimeters

44. R.S. Orr 2009 TRIUMF Summer Institute PN Junction

45. SCT barrel

46. Pixel Layer-2 – half shell Pixel Layer2, once clamped, outside Pixel Layer2, once clamped, inside “Ready for installation” date is 1 st April 2007

47. R.S. Orr 2009 TRIUMF Summer Institute ATLAS Wedge  Different Particles detected by different techniques.  Tracks of Ionization – Tracking Detectors  Showers of Secondary particles – Calorimeters

48. Liquid Argon/Metal Charged Particle Kinetic Energy of Particle Converted to Ionization Of Liquid Argon Electrical Signal Proportional to Incoming Energy Why Is It Called a Calorimeter? Readout Electronics

49. R.S. Orr 2009 TRIUMF Summer Institute Comparison of Hadronic & Electromagnetic Showers

50. LAr and Tile Calorimeters Tile barrelTile extended barrel LAr forward calorimeter (FCAL) LAr hadronic end-cap (HEC) LAr EM end-cap (EMEC) LAr EM barrel

51. LAr Forward Calorimeters FCAL C assembly into tube – Fall 2003

52. Oct 2002

54. Hadronic Endcap

55. HEC – FCAL Assembly