A central rapidity straw tracker and measurements on cryogenic components for the Large Hadron Collider

This thesis is divided into two parts in which two different aspects of the Large Hadron Collider (LHC) Project are discussed. The first part describes the design of a transition radiation tracker (TRT) for the inner detector in ATLAS. In particular, the barrel part was studied in detail. The barrel TRT consists of 52 544 1.5-m-long proportional tubes (straws), parallel to the beam axis and each with a diameter of 4 mm. The detector is divided into three module layers with 32 modules in each layer. The preparatory study comprises: module size optimization, mechanical and thermal calculations, tracking performance and material budget studies.