Speaker
Description
The LHCb experiment at the Large Hadron Collider will undergo a major
high-luminosity upgrade during Long Shutdown 4, targeting instantaneous luminosities
up to 1.5×1034 cm−2 s−1, representing a tenfold increase over previous
operations. This will lead to a significant rise in recorded data, from 50 fb−1 to
300 fb−1, and poses challenges for the current tracking system due to increased
occupancy, harsh radiation, and strict material budget constraints.
To address these challenges, the downstream tracker will be replaced with the
Mighty Tracker, a hybrid detector combining monolithic High Voltage CMOS
(HV-CMOS) silicon pixel sensors in the inner region and scintillating fibres in
the outer region. The silicon pixel modules are based on HV-CMOS pixel sensor
technologies currently under development, with MightyPix as a leading candidate.
These sensors provide efficient charge collection, nanosecond-level timing
resolution (∼ 3 ns), and excellent radiation tolerance, making them suitable for
operation under the high-luminosity conditions of the LHCb Upgrade II. Thinning
the sensors to 150 μm minimises inactive volume while keeping the material
budget low. The outer scintillating fibre region preserves coverage in the peripheral
detector acceptance. The silicon sensors are mounted on a lightweight
composite support structure, ensuring both mechanical stability and efficient
thermal management under extreme hit rates (18MHz/cm2) and high radiation
fluence (∼ 6×1014 MeV neq/cm2). This contribution presents the ongoing R&D
efforts and summarises the performance results from thermo-mechanical design
and prototype testing.