Roy Smits

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• Physics Reminder
• Design Considerations
• Overview of PHOBOS Detectors
• Costs and Infrastructure

• Roy Smits
• Ralf Kissman
• Ronald Bruijn
• Margarita Chichikina

International Summer School on Particle and
Nuclear Astrophysics
28 - 8 - 2003
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Physics Reminder

• Quark Gluon Plasma (QGP)
• New state of matter
• Early Universe

Rember last weeks lecture Ultrarelativistic
Heavy Ion Collisions
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Signatures of QGP

• Multiplicity enhancement
• Enhancement at low transverse momentum
• Density dependence of M
• Intensity interferometry
• ...

Not measured yet
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Example 1
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Example 2
See blackboard
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Design Considerations/Requirements

• Largest possible ? (rapidity) range

• Lowest possible momentum threshold
• Unbiased trigger
• Au-Au collisions up to
• 200 GeV

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RHIC (Relativistic Heavy Ion Collider)
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Overview of PHOBOS detectors

• Multiplicity Array
• Silicon pads
• Vertex Detector
• Spectrometer
• Silicon array
• Time of flight walls
• 2.1 Tesla Magnet
• Triggers
• Paddle Counters
• Cherenkov Counters
• Zero degree Calorimeter

Coverage over almost 4? (? ? 5.4)
Optimised for low transverse momentum (little
material in between) Momentum threshold 10 MeV
detectable 30 MeV p analysed
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Schematics of PHOBOS Detector
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Costs and Infrastructure

• CHEAP!

7M
Small group (70 scientists)
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Summary

• Large rapidity range
• Signatures of phase transition
• Low transverse momentum
• Measurement of fireball
• Minimal costs (7 M)
• Unique addition to other experiments
• Complete control by small team

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