1.1 The ALICE Experiment
3
Fig. 1.2 Schematic overview of the ALICE detector showing where the Time Projection Chamber
and Muon Tracking Chamber are situated in the detector [1]
end plates, with a total of 557 568 readout pads. A central high voltage electrode
located at its axial centre divides the active drift volume into two halves. A schematic
overview of the detector can be seen in Fig. 1.3.
The beams colliding at the centre of the cylinder create charged particles, which
traverse through the gas, ionizing the gas atoms along the way and creating long
tracks. Due to the large magnet that is surrounding the detector, the trace will be
bent weaker or stronger in one way or the other depending on the particle’s electric
charge and momentum. Because of the electric field set up between the centre and
the end plates, the liberated electrons created in the ionization will drift at a constant
speed towards the readout pads on the end plates. The density of electrons along
the track will depend on the momentum and identity of the particle. The end-caps
were equipped with MWPCs until 2018; anode wires are strung up close to the end
plates, which will create amplification of the signal through the avalanche effect.
The positive ion cloud created in the avalanche process induces an image charge on
the cathode pads, which is then propagated to the front-end electronics. The signals
induced on the arrangement of pads provide a measurement of the track projection
onto the end plate. The third coordinate of the track is extracted from the measurement
of the drift times of the ionization electrons.
3
Fig. 1.2 Schematic overview of the ALICE detector showing where the Time Projection Chamber
and Muon Tracking Chamber are situated in the detector [1]
end plates, with a total of 557 568 readout pads. A central high voltage electrode
located at its axial centre divides the active drift volume into two halves. A schematic
overview of the detector can be seen in Fig. 1.3.
The beams colliding at the centre of the cylinder create charged particles, which
traverse through the gas, ionizing the gas atoms along the way and creating long
tracks. Due to the large magnet that is surrounding the detector, the trace will be
bent weaker or stronger in one way or the other depending on the particle’s electric
charge and momentum. Because of the electric field set up between the centre and
the end plates, the liberated electrons created in the ionization will drift at a constant
speed towards the readout pads on the end plates. The density of electrons along
the track will depend on the momentum and identity of the particle. The end-caps
were equipped with MWPCs until 2018; anode wires are strung up close to the end
plates, which will create amplification of the signal through the avalanche effect.
The positive ion cloud created in the avalanche process induces an image charge on
the cathode pads, which is then propagated to the front-end electronics. The signals
induced on the arrangement of pads provide a measurement of the track projection
onto the end plate. The third coordinate of the track is extracted from the measurement
of the drift times of the ionization electrons.