Status of the construction and performances of the neutron zero degree calorimeters of the ALICE experiment

The details of the construction of the neutron Zero Degree Calorimeters (ZN) of the ALICE Experiment, as well as their performances, will be presented. These spaghetti calorimeters will measure the energy lost by spectator nucleons in heavy-ion collisions. They are made of an absorber (tungsten alloy) filled with silica fibers, in which the charged particles of the shower produce Cherenkov light. The final neutron calorimeters have been built and their performances studied at the CERN SPS using pion and positron beams with momentum ranging from 50 to 150 GeV/c. The main features like linearity of the response and resolution as a function of energy will be presented.