1. Lecture 18 - Detectors Detector systems
Momentum of charged particles (trackers)
Energy of particles (calorimeters)
Detector at a collider experiment.
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2. The purpose of a detector
jet e-
g,Z0
jet
jet
jet
jet
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3. Electron-proton DIS
g,Z0
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4. DIS event at H1 detector at HERA ep collider
(4) Muon Tracker m-
(3) Had. Calo
jet
e- (30 GeV)
p (820 GeV)
(1) Tracker
(2) EM Calo e-
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5. H1 Detector
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6. (1) Tracking system z y x m- FK7003 (2) EM Calo (1) Tracker
(3) Had. Calo
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7. Tracker – Drift Chamber
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8. Measuring momentum y x
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9. Measurements of ionisation energy loss
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10. Tracking Chambers H1
Different technologies/geometric arrangements available.
Drift chambers.
Time projection chambers
Semi-conductors trackers….
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11. Summary of trackers and some observationsz
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12. Calorimeters What is the purpose of the calorimeters ?
To measure the electromagnetic and hadronic energy loss separately arising from a system of particles.
To measure the ’full energy’ arising from a collision (as much as possible). We’d like to be able to reconstruct what happened in the fundamental particle collision
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13. Sampling Calorimeters
We know that particles produce some type of shower when they go through material (lecture 17). Used for electromagnetic and hadronic calorimeters.
Sampling calorimeter – thin blocks of dense material interleaved with an active material which can measure the shower
Many different possibilities
Dense blocks (eg lead) interleaved with scintillators (for light).
Dense blocks with liquid argon (for ionisation) ….
Active layer
Dense material
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14. (2) Electromagnetic calorimeter
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15. (3) Hadronic Calorimeter
EM Cascade
Nuclear cascade
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16. (4) Muon tracker m-
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17. Summary so far
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18. Finding energetic weakly interacting neutral particles
not measured W-
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19. Missing transverse momentum from charged current DIS data at HERAW-
Prediction for CC
cross section.
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20. ATLAS experiment at the LHC
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21. Production of supersymmetric particles at the LHC
Missing transverse momentum (simulation, obviously)
SUSY
SM Backgrounds
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22. Summary
A typical collider experiment consists of tracking systems and calorimeters
Many different technologies.
Reconstruction of momentum and energy
Particle identification.
We’ve reached the end.
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