Speaker
Description
During the second long shutdown of the Large Hadron Collider at CERN, the LHCb experiment has been upgraded and the new detector is currently operating at the LHC. The Vertex Locator (VELO) is the detector surrounding the interaction region of the LHCb experiment, responsible of reconstructing the proton-proton collision (primary vertices) as well as the decay vertices of long-lived particles (secondary vertices). The VELO consists of 52 modules with hybrid pixel detector technology. The upgrade VELO encompass an enhanced track reconstruction speed and precision, even at the expected higher occupancy conditions of the upgrade, due to its pixel geometry as well as a closest distance of approach to the LHC beams, with the first sensitive pixel being at just 5.1 mm from the beam line. Cooling is provided by evaporative CO2 circulating in 500 $\mu$m thick silicon microchannel substrates. The sensors consist of 200 $\mu$m thick n-on-p planar silicon sensors, read out via 3 front-end ASICs. The detector contains 41 million 55$\mu$m x 55$\mu$m pixels, read out by a custom developed front-end ASIC (VeloPix). During the lifetime of the detector, the sensors are foreseen to accumulate an integrated fluence of up to 8x10$^{15}\,$1MeV$\,$n$_{\rm eq}\,$cm$^{-2}$, roughly equivalent to a dose of 400 MRad. Moreover, due to the geometry of the detector, the sensors will face a highly non-uniform irradiation, with fluences in the hottest regions expected to vary by a factor 400 within the same sensor. The detector has started operation in 2022. The new detectors have performed very well throughout the first year of Run 3, but face new operational challenges with increased radiation damage foreseen till the end of this run. The design, operation and early results evaluating the radiation damage and detector performance throughout the first year of operation in LHC run 3 will be presented.
| Collaboration | The LHCb Collaboration |
|---|---|
| Role of Submitter | The presenter will be selected later by the Collaboration |
