TOB
Tracker Outer Barrel (TOB)
Detector
Tracker
Outer
Barrel
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A sub-detector of the Compact Muon Solenoid
(CMS) experiment in the CERN’s future Large
Hadron Collider (LHC)
Main responsible parties of the TOB construction:
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•
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CERN
Fermi National Accelerator Laboratory (USA)
Helsinki Institute of Physics (FIN)
University of California, Santa Barbara (USA)
TOB
Tracker
Outer
Barrel
CERN
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CERN = European Organization for Nuclear Research
Founded in 1954, today 20 member states
The world's largest particle physics centre with scientists
from 500 universities from 80 countries.
Goal: Study what matter is made of and what forces hold
it together
CERN provides tools for the scientists:
• Accelerators and Colliders that accelerate particles to almost the
speed of light and make them collide
• and Detectors to make the particles visible
TOB
Tracker
Outer
Barrel
CERN’s accelerators aerial view
TOB
Tracker
Outer
Barrel
Large Hadron Collider (LHC)
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CERN’s present main project, due to start in year 2007
Will collide beams of protons at an energy of 14 TeV
• 1 TeV is about the energy of motion of a flying mosquito. LHC
squeezes that energy into a space about a million million times
smaller than a mosquito.
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Tries to answer unsolved questions:
• Why elementary particles have mass? What is the “origin” of
mass? Is the “Higgs” particle an answer to these?
• Plus many other subjects, like Supersymmetry, Antimatter, any
new form of matter, etc. etc.
TOB
Tracker
Outer
Barrel
Compact Muon Solenoid
(CMS) experiment
Muon detectors
Magnet
Calorimeters
Tracker
Total weight:
Diameter:
Length:
Magnetic field:
14,500 tons
14.6 m
21.6 m
4 Tesla
Tracker requirements
and technologies
TOB
Tracker
Outer
Barrel
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Measurement of particle tracks with 50 m precision in a
volume of 5.4 m in length and 2.4 m in diameter
• High-precision silicon pixel and silicon strip detectors
• Dimensionally very stable structures
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Transparency to particles
• Minimize material
• Use of light-weight constructions (composites, plastics, aluminum)
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Reliable operation during 10 years in high radiation levels,
and high magnetic field
Very little possibilities for maintenance and repair
• Satellite-level of reliability required
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And all this with acceptable costs…
TOB
Tracker
Outer
Barrel
CMS Tracker layout
Outer Barrel
- TOB -
2,4 m
Inner Barrel & Disks
- TIB & TID -
End Caps – TEC
(at the two ends, one
shown only)
Pixel detector
Beam pipe
TOB
Tracker
Outer
Barrel
TOB basic info
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6 detector layers.
Dimensions:
• 550 mm < R < 1165 mm in radius
• -1230 mm < Z < +1230 mm in length.
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Mass:
•
~ 700 kg own mass
•
+ 300 kg supported (TIB + TID + Pixel)
•
= total ~ 1000 kg supported
Supported from Tracker Support Tube’s rails.
TOB
Tracker
Outer
Barrel
TOB Silicon module
Carbon-fiber support frame
512 (or 768)
narrow “strips”
side by side
here on the
silicon substrate
Read-out
electronics
and cabling
TOB
Tracker
Outer
Barrel
TOB Rod
with Cables and Cooling
Module support blocks
Cooling pipe
Module frame
The Aluminium blocks
supporting the Si modules
provide thermal contact
between module frames and
cooling pipes (Cu-Ni alloy)
TOB
Tracker
Outer
Barrel
TOB Rod
with silicon modules
Silicon modules
on the Rod
Protection box for
testing of the Rod
TOB
Tracker
Outer
Barrel
TOB Rod measurements
24 module supports / rod
12 dowel pins / rod
Geometrical precision of the module
supports and positioning dowel pins
measured to be better than 50 m
over the whole rod area.
TOB
Tracker
Outer
Barrel
Tracker Outer Barrel
(TOB) Structure
688 carbon-fiber “Rod”
units are inserted in
the support “Wheel”