An Optical Readout System for the LHCb Silicon Tracker

The LHCb experiment is to precisely measure the CP-violation parameters in the B-meson decay. It is one of the four large experiments which is currently being installed at the Large Hadron Collider (LHC) and planned to start taking data in 2007. The Silicon Tracker covers the tracking volume around the beam pipe with the highest track densities. The huge amount of data generated during operation has to be transported to the processor farm for follow-up track recognition and analysis. This work presents a digital optical readout link which transmits the tracking information with a rate of 2.7 Terabit/s over a distance of 100 m from the detector to the computer farms. Special attention was paid to the radiation tolerance of the transmitting section, as its location is exposed to ionizing particles and radiation levels similar to those encountered in space applications. The design was aimed to provide a modular system which simplifies production, testing, commissioning and maintenance. Where possible, commercial off-the-shelf components were used to reduce the overall cost of the system. For commercial components exposed to radiation, several irradiation campaigns were performed to qualify them for use in the LHCb environment.