Detector Seminar

LHCb SciFi: From performance requirements to an operational detector

by Sune Jakobsen (CERN)

40/S2-D01 - Salle Dirac (CERN)

40/S2-D01 - Salle Dirac


Show room on map

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 μm and a hit efficiency larger than 99%.

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.

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. 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.

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.

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.


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Organized by

Burkhard Schmidt (EP-DT)

There is a live webcast for this event