Technical Design Report for the Muon Forward Tracker

The ALICE physics programme after the second LHC Long Shutdown (LS2) is mostly devoted to high precision measurements of hard probes (heavy-flavour hadrons, quarkonia, photons and jets). The strategy for the detector upgrade is reported in the ALICE Upgrade Letter of Intent. The present Technical Design Report describes the Muon Forward Tracker (MFT), a new Si-tracking detector designed to add vertexing capabilities to the MUON spectrometer. The MFT will allow ALICE to extend the precision measurements of the QGP fun- damental properties towards the forward rapidity region. The MFT will sub- stantially improve the present performance of the MUON spectrometer and open the path to new measurements not accessible with the present apparatus (open charm/beauty separation, ψ in central Pb–Pb collisions and J/ψ from b-hadron decays measurements). The MFT consists of two half-cones containing five de- tection half-disks placed along the beams axis between −460 mm and −768 mm away from the average position of the ALICE interaction point. The MFT covers the pseudo-rapidity domain −3.6 < η < −2.5. The basic detection element is a silicon pixel sensor, developed by the ALICE pixel groups for both ITS and MFT. The 896 silicon pixel sensors of the MFT will be assembled, using the same technology as for the new ITS, on 280 ladders of 1, 2, 3, 4 or 5 sensors each. A read-out electronics, common to both ITS and MFT, is jointly developed by the two projects.