Speaker
Description
The LHCb experiment is planning a major upgrade (Upgrade II) during the LHC Long-Shutdown 4 to fully exploit the flavour physics potential of the High Luminosity LHC. The Upstream Tracker (UT), a silicon strip subdetector and key component of the current LHCb tracking system, will have to be upgraded to tackle the higher event rate and harsher radiation environment. A MAPS-based pixel UT has been proposed since the Upgrade II Framework TDR, and various scoping scenarios have been studied after implementing the detector concept in simulation. We will report key conclusions from the simulation study, including the UT-related tracking performance with different designs. Based on the simulation the key specifications for sensor chip are derived, including good spatial resolution, nanosecond-level timing for bunch tagging, radiation hardness up to $3 \times 10^{15} n_{eq} cm^{-2}$, just to name a few most challenging ones. The sensor options will be discussed, including common development with Mighty Tracker, and dedicated HVCMOS sensors in smaller feature size of 55nm process which is expected to be radiation hard. The optimization of the module and stave for minimal dead area and material budget are ongoing; prototyping has been starte. Plans for development towards the TDR and beyond will also be briefly mentioned.
