Monitoring and calibration of the ALICE time projection chamber

The aim of the A Large Ion Collider Experiment (ALICE) experiment at CERN is to study the properties of the Quark–Gluon Plasma (QGP). With energies up to 5.5 A T eV for Pb+Pb collisions, the Large Hadron Collider (LHC) sets a new benchmark for heavy- ion collisions, and opens the door to a so far unexplored energy domain. A closer look at some of the physics topics of ALICE is given in Chapter 1. ALICE consists of several sub-detectors and other sub-systems. The various sub- detectors are designed for exploring different aspects of the particle production of an heavy-ion collision. Chapter 2 gives some insight into the design. The main tracking detector is the Time Projection Chamber (TPC). It has more than half million read-out channels, divided into 216 Read-out Partitions (RPs). Each RP is a separate Front-End Electronics (FEE) entity, as described in Chapter 3. A complex Detector Control System (DCS) is needed for configuration, monitoring and control. The heart of it on the RP side is a small embedded computer running the FeeServer software, providing a means for remote configuration and continuous monitoring of the FEE. Chapter 4 gives details of the implementation of this software, and also shows the performance measurements. In Chapter 5, potential improvements to the FeeServer class factorisation is discussed. Converting the electronics signals, as measured by the sub-detectors, into useful physics data is a complicated process. This is called the calibration. Every sub-detector has its unique set of calibration tasks and challenges. Chapter 6 looks into some of the aspects of calibrating the electron drift of the TPC. This discussion is continued in Chapter 7, where the concrete AliRoot framework for some of the TPC calibration tasks is described. Chapter 8 dwells on the specifics of the TPC drift velocity calibration. Finally, the status of the effort is given in Chapter 9.