The ALICE Time-Projection Chamber (TPC) is the main device, in the ALICE ‘central barrel’, for tracking of charged particles and particle identification. The ALICE TPC was designed to cope with the highest conceivable charged particle multiplicities predicted, at the time of the Technical Proposal (TP), for central Pb–Pb collisions at LHC energy, i.e. rapidity densities approaching dNch/dy = 8000 at center-of-mass energy of 5.5 TeV.1 Its acceptance covers 2π in azimuthal angle and a pseudo-rapidity interval |eta| < 0.9. Including secondaries, the above charged particle rapidity density could amount to 20 000 tracks in one interaction in the TPC acceptance.
On Dec. 6th, after a successfull restart of the LHC, first collisions were recorded in the ALICE TPC. Below are a few screenshots from the online-monitor.