LHCb SciFi: From performance requirements to an operational detector

<!--HTML--><p><span><span><span>The SciFi tracker of LHCb is the replacement of the Outer Tracker (based on gas straw tubes) and Inner Tracker (Silicon microstrips) by a single detector technology. The detector consists of 3 tracking stations with 4 independent planes and has a total active surface of ~340 m2. It aims for a spatial hit resolution of better than 100 </span>μ<span>m and a&nbsp;hit efficiency larger than 99%.</span></span></span></p> <p><span><span><span>The active element of the SciFi consists of 250 μm thick and 2.5m long scintillating fibres arranged as hexagonally close-packed six-layer mats of 135mm width. Eight of these mats are joined together to form 5m long and 52 cm wide modules. One end of the fiber carries a mirror and the scintillation light exiting at the other end is detected by linear arrays of SiPM detectors.</span></span></span></p> <p><span><span><span>For the 40 MHz readout, a custom-designed ASIC is is used. It is followed by digital boards for clustering and data-reduction to cope with the 40 MHz readout requirement.&nbsp;Control and data-transmission is ensured by optical links. The detector has been assembled at CERN during LS2 of the LHC. This includes mechanics, cabling, Front-End electronics and services. The detector is segmented into 12 pieces called C-frames due to the geometric shape. Each C-frame has been thoroughly tested as part of the assembly.</span></span></span></p> <p><span><span><span>The assembly was followed by the installation of the detector in the LHCb cavern. A large number of services like dry gas, SiPM cooling, isolation vacuum, Front-End electronics cooling, low voltage and bias has also been prepared.</span></span></span></p> <p><span><span><span>The detector is now fully installed and the commissioning is ongoing. First performance studies of the services and first calibration confirm the operational readiness of the detector. </span></span></span></p>