Studies on the Optical Readout for the ATLAS Pixel Detector

The particle physics is concentrating on the research of the structure of the matter which is observable in our world. How is this world built. Which particles exist, which are necessary to build up the world? How is this matter kept together, what are the interactions between the known particles? The answers to these questions are obtained by observing the known particles, to study their properties, and to search new for particles. Models are developed to describe all the observations. Experiments are performed to proove the models. The best prooven model to describe many of the observations is the Standard Model. The Standard Model is elucidated in Chapter 1. It is tested very precisely by experimental measurements in the last years, but cannot explain all phenomena of nature. To discover the last not observed particle of the Standard Model, the Higgs boson, and to extend the model further experiments are needed. To study the elementary particles machines and instruments are necessary to produce and measure the particles and their properties. In the last 50 years an enormous effort has been made to develop new machines to produce particles at always higher rates and energies. The more massive the particles are the more energy is needed to produce them. To increase the machine energy drives the physicists and engineers to develop new machines and experimental instruments. The newest machine will be the Large Hadron Collider which is under construction at CERN in Geneva and will start operation in 2007. This machine accelerates protons in a ring to an energy of 7TeV in opposite directions. These protons will collide at four interaction points. Here experiments will be installed to measure the products of the collisions: ALICE, ATLAS, CMS, and LHC-b. The ATLAS experiment is the largest experiment. It is described in Chapter 2. This work has been done as a part of the development of the innermost subdetector of the ATLAS detector, the pixel detector. The pixel detector and its readout is explained in Chapter 3. The steering and the data readout of the more than 80000000 channels of the pixel detector is performed through an optical data transmission line, the optical link. This optical link and espacially its off-detector interface, the Back of Crate card, is the central topic of this thesis. The Back of Crate card has been studied in its function and its operation performance in detail for this work. The card has been examined starting with the production (see Chapter 5), introducing it into system tests (see Chapter 6), and operating the card in a test beam experiment very similar to the final ATLAS experimental usage (see Chapter 7). One important task of the Back of Crate card is the adoption of the timing for the pixel detector and its readout. The timing functionality of the pixel detector was studied for the first time in a real experimental environment using traversing particles in the test beam experiment. The behaviour of the Back of Crate card and the results for the test beam study promise a good performance in the final ATLAS experiment. Finally this work and the results are summerised and an outlook to the forthcoming tasks is given.