compact muon solenoid detector - indico€¦ · piotr traczyk ncbj warsaw/cern. 2 cms detector...

TheCompact Muon Solenoid

Detector

Piotr TraczykNCBJ Warsaw/CERN

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CMS detector overview

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The CMS Solenoid● CMS is built around a superconducting solenoid

generating a magnetic field of 4 Tesla● The current necessary for this – 20 kA...● Superconducting NbTi wire cooled to ~4K● 13m length, 6m inner

diameter – enough to fit the tracker and calorimeters inside

● (cost ~80 MCHF)

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ATLAS A Toroidal LHC Apparatus

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CMS Compact Muon Solenoid

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Magnets in particle detectors

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Two ways to detect a particle (in CMS)

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Two ways to detect a particle (in CMS)

See the track Or Catch

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Two ways to detect a particle (in CMS)

Tracking detector Or

Calorimeter

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Particle identification in CMS

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The Inner Tracker● Measures the trajectories of

charged particles momentum = 1/curvature

● The biggest silicon detector in history, over 220m2 of silicon

● Inner part – 3 layers of pixel detectors, outer part 10-11 layers of silicon microstrips

● 75 141 milions of read-out channels

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Event „pile-up”

In the LHC, several proton-proton collisions can occur in a single bunch crossing (The image shows an event with 29 reconstructed vertices)

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Electromagnetic Calorimeter● Electron and photon energy measurement● ~75 000 PbWO

4 crystals

● Homogeneous detector - crystals act as both the absorber and the scintillator

● Very good energy resolution

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Hadron Calorimeter ● Jet energy measurement● Brass absorber interleaved

with scintillator layers● Steel blocks with embedded quartz fibers in the

„forward” part

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The Muon System – Drift Tubes● Muon trajectory measurement (barrel)● Measured quantity – drift time of

electrons produced by the passing muon● Known drift velocity distance →

measurement (~50-200mm precision)● Alignment very important

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Trigger

The H → gg channel

One of these plots contains the (simulated) Higgs boson signal.

Can you spot it?

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The H → gg channel

One of these plots contains the (simulated) Higgs boson signal.

Can you spot it?

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The H → gg channel

One of these plots contains the (simulated) Higgs boson signal.

Can you spot it?

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The H → gg channel

One of these plots contains the (simulated) Higgs boson signal.

Can you spot it?

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The H → gg channel

One of these plots contains the (simulated) Higgs boson signal.

Can you spot it?

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The H → gg channel

One of these plots contains the (simulated) Higgs boson signal.

Can you spot it?

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The H → gg channel

One of these plots contains the (simulated) Higgs boson signal.

Can you spot it?

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Once more:

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A proton-proton collisionas seen by CMS

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The End