Neutron Production and Zero Degree Calorimeter Acceptance at LHC

We calculate cross sections for the far forward LHC detectors to be used for luminosity measurement. A simple model, based on a parametrization of available inclusive neutron data and the assumption that 2 arm rates in non-diffractive events are uncorrelated, is introduced. The calculated rates are in reasonable agreement with preliminary data from RHIC and we are now comparing with rates at 3 LHC energies.