Speaker
Description
TLHCb experiment is about to implement a major upgrade, scheduled to start
data taking in LHC Run III. The Vertex Locator (VELO) is the silicon detector
surrounding the interaction region. It will be completely replaced with a new
light weight pixel detector capable of 40 MHz readout.
The upgraded VELO modules will each host 4 silicon hybrid pixel tiles, each
read out by 3 VeloPix ASICs. The silicon sensors must withstand an integrated
fluence of up to 8$\times 10^{15} 1 MeV n_eq/cm^{2}$, a roughly equivalent dose
of 400 MRad. The highest occupancy ASICs will have pixel hit rates of 900
Mhit/s and produce an output data rate of over 15 Gbit/s, with a total rate of
1.6 Tbit/s anticipated for the whole detector. The detectors are located in
vacuum, separated from the beam vacuum by a thin custom made foil. The foil
will be manufactured through a novel milling process and possibly thinned
further by chemical etching.
The VELO upgrade modules are composed of the detector assemblies and
electronics hybrid circuits mounted onto a cooling substrate, which is composed
of thin silicon plates with embedded micro-channels that allow the circulation
of bi-phase CO$_2$. The front-end hybrid hosts the VeloPix ASICs and a GBTx
ASIC for control and communication. The hybrid is linked to the opto-and-power
board (OPB) by 60 cm electrical data tapes running at 5 Gb/s. The tapes must be
vacuum compatible and radiation hard and are required to have enough
flexibility to allow the VELO to retract during LHC beam injection.
The entire assembly must respect
strict deformation and bending constraints, have a high radiation tolerance
and very low outgassing levels. The module design will be described
