III-1 1 Name of the Chapter 1.1 Vertex Detector

The physics motivation for the vertex detector (VTX) has been discussed in the Detector Concept section of this report. Section 1.1.1 indicates how this leads to performance goals for the detector and Section 1.1.2 discusses the machine-related issues which constrain the vertex detector design. Combining the performance goals with the restrictions from the machine leads to an acceptable compromise for the detector features, as discussed in Section 1.1.3, as are other points which are common to all the technology options. Section 1.1.4 discusses the three technology options which are currently considered for the TESLA vertex detector, namely charge-coupled devices (CCDs), CMOS pixels and hybrid pixel sensors. How well does a detector which can be built, accessed and serviced satisfy the physics goals? The generic detector performance is discussed in Section 1.1.5. The more detailed aspects of the performance are mentioned in the Tracking System Performance section, while the global performance in terms of b and charm tagging is presented in the Detector Performance section. The conclusion from these studies is that, by careful control of backgrounds, the TESLA interaction region can be made particularly favourable for the construction of a vertex detector of unprecedented performance, well-matched to the physics goals of the TeV