Abstract:

LHCb will produce B-mesons at high rate and allows studying CP violation and heavy-quark systems. In addition, precise measurements of B oscillations and CP asymmetries can reveal new physics. Displaced secondary vertices are a special feature of B-meson decays and consequently vertex reconstruction is a fundamental requirement for the LHCb experiment. LHCb places thin silicon strip detectors in the LHC vacuum at only 8-mm distance from the beams. The LHCb detector has been optimized, especially its tracking scheme, to improve the physics performance. The silicon detectors are readout by the Beetle, a deep-submicron frontend chip, specially designed for the vertex detector. The chip is designed to withstand the high radiation levels close to the LHCb interaction point. The frontend amplifier and shaper have strict constraints to cope with the 40 MHz LHC clock. The Beetle chip is bonded to prototype silicon detectors and tested in several testbeam runs at CERN. The current design of the vertex detector meets the LHCb requirements and provides a vertex resolution along the beam direction of about 40 micro-meter to resolve the fast Bs oscillations.