The FEE Server Control Engine of the ALICE-TRD - Westfälische ...

1 Introduction
The standard model of elementary particles describes the particles we observe in the
universe and the ways these particles interact. 1 According to the standard model
all observed hadrons like protons or pions are composed of gluons and two or three
quarks/anti-quarks. Quantum chromodynamics (QCD) describes the interactions between
these particles.
In normal baryonic matter each quark, anti-quark or gluon is assigned to one hadron.
Free (anti-)quarks or gluons have never been observed. This behavior is called confinement.
Another important property of the QCD is asymptotic freedom. At high energies,
which is equivalent to small distances, the coupling strength between quarks and gluons
becomes weak.
In the very early universe, up to about 10 µs after the Big Bang the temperature was
above a critical temperature Tc = 150 − 190 MeV [BMS07]. At these temperatures quarks
and gluons are not confined to hadrons but can move freely. This state is called a quarkgluon
plasma (QGP). When the universe expanded, it cooled down and the quarks and
gluons were confined inside hadrons. In the present-day universe a QGP may only exist
inside of neutron stars if the densities are high enough.
In a laboratory the QGP can be created by colliding two nuclei at ultra-relativistic
center-of-mass energies. For a short time the energy density in the collision zone is high
enough to create a QGP. Measuring the properties of the QGP and investigating the phase
transition from a QGP to normal baryonic matter is very important. Such measurements
can be used to check QCD calculations and they increase our knowledge about the history
of the universe. The Super Proton Synchrotron (SPS) at CERN was the first accelerator
which saw hints for the creation of a QGP [CER00]. In 2009 the new Large Hadron Collider
(LHC) at CERN near Geneva will start its regular operation. It is capable to collide
heavy ions at center-of-mass energies up to √ sNN = 5.5 TeV which is about 30 times
more then RHIC 2 energies [BMS07]. However, most of the time the LHC will run protonproton
collisions mainly to look for the Higgs boson which is the last undetected particle
of the standard model and search for physics beyond the standard model. ALICE as one
of the four experiments at LHC is the only dedicated heavy ion experiment.
In this diploma thesis the control engine for the transition radiation detector (TRD) of
ALICE has been redesigned, implemented and tested. Based on this software a procedure
was developed to check proper cooling of the front end electronics of the TRD.
1 Nowadays it is known that the standard model cannot be complete because it fails describing some important
observations like the nature of dark matter.
2 The Relativistic Heavy Ion Collider (RHIC) located at the Brookhaven National Laboratory at Long Island
(USA) was the most powerful heavy ion collider before LHC was build
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