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ZEUS
Members of the
ZEUS group in front of the detector
The ZEUS detector has dimensions of 12 m x 10 m x 19 m, and Its total weight is 3600 tons. It is staffed by han 450 physicists from 12 countries, making it a truly international scientific collaboration.
Click on various parts of the image below to show what pieces of the detector do.
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for events in ZEUSCentral
Tracking Detector (CTD),
FTD and RTD
The Central Tracking
Detector, and the Rear and Front Tracking
Detectors, are used to measure the paths of charged
particles from HERA's high energy collisions. The
detector lies within a magnetic field which bends the
paths of charged particles. Particles with a large
momentum travel in almost straight paths, while very low
momentum particles bend to make tight spirals. The
tracking chamber contains many fine wires, with some at
different angles to each other, and the chamber is filled
with a gas. When a charged particle passes through
the gas it ionizes the gas along the path it follows. The
electrons emitted from the ionized gas drift in the
chamber towards the wires, where they produce a
signal. This allows the position of the particle to
be calculated accurately.
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Electromagnetic Calorimeter (EMC or ECAL)
The name "calorimeter" normally refers to a device that measures heat. Particle physicists however use this term for any device that is used to measure the energy of a particle. It achieves this by absorbing all the energy of the particle, and releasing a shower of low energy particles. By evaluating the number of particles produced in the shower the energy of the the original particle can be deduced. The EM calorimeter is designed to stop particles such as electrons and photons. Hadrons (particles made from quarks) are relatively unhindered by this section of the calorimeter, and pass through leaving only a small trace of energy. The calorimeter is made from layers of uranium and scintillator.
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Hadrons Calorimeter (HAC or HCAL)
The hadron calorimeter
works in a similar way to the EMC but is much thicker so
as to absorb all the hadron energy.
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Muon chamber
Beyond all the other
detectors are the muon chambers. Most particles
will have been stopped by now by the other sections of
the detector. Muons are the only charged particles
to reach this far, so it is only here that they reveal
their identity.
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See event example in More Examples