Speaker
Giovanna Puddu
(INFN Cagliari)
Description
The Zero Degree Calorimeters (ZDCs) for the ALICE experiment will estimate
the centrality of the ion-ion collision by measuring the energy carried away
by the non-interacting nucleons (spectators). The spectator protons and
neutrons will be separated from the ion beams by the separator magnets of
the LHC beam optics and respectively detected by the proton (ZP) and the
neutron (ZN) calorimeters. ZDCs are spaghetti calorimeters, which detect
the Cherenkov light produced by the shower particles in silica optical fibres
embedded in a dense absorber. The technical characteristics of ZP and ZN
detectors are described. The calorimeters have been tested at the CERN SPS
using hadron and electron/positron beams with momenta ranging from 50
to 200 GeV/c; the ZN detector’s behaviour has also been studied with an
Indium beam of 158 A GeV/c. The beam test results are presented: the
calorimeters’ response, the energy resolution and the localizing capability.
Also the signal uniformity and a comparison between the transverse profile
of the hadronic and electromagnetic shower are discussed. Moreover the
differences between the ZP detector’s responses to protons and pions of the
same energy have been investigated, exploiting the proton contamination in
the positive pion beams.
Authors
Giovanna Puddu
(INFN Cagliari)
Nora De Marco
(INFN Torino)
