Speaker
Summary
The Zero Degree Calorimeters (ZDCs) for the ALICE experiment will
measure
the energy of the spectator nucleons in heavy ion collisions at
the CERN LHC.
The ZDCs consist of a neutron (ZN) calorimeter, placed between
the two beam
pipes, and a proton (ZP) calorimeter, positioned externally to
the outgoing
beam pipe at 116 m from the interaction point.
The ZDCs are spaghetti calorimeters, which detect the Cherenkov
light
produced by the shower particles in silica optical fibers
embedded in a dense
absorber.
In summer 2007 the ZN and ZP calorimeters have been integrated on
the surface
on a movable platform and then installed in the LHC tunnel.
The results of the commissioning on the surface, in particular the
solutions adopted to control the stability of the PMTs response will
be shown: light injection with a laser diode and cosmic rays.
The forseen physical calibration in Pb-Pb collisions will be also
discussed.
Finally the first measurements of the commissioning in the LHC
tunnel will be
presented.
