On the simulation of limit thresholds for ISOLDE decay station neutron detector

The recently comissioned ISOLDE decay station neutron detector (IDSN) efficiency was calibrated with a standard 252Cf neutron source, using lower threshold limits set at 0, 31 keV and 59.5 keV, and upper threhold of 3840 keV. Geant4 simulations were run to compare with the experimental efficiency where new detector limits were sought to fit the experimental data. Suitable values of limit thresholds were found that properly fit the simulation with experimental lower neutron energies, below 1 MeV, but strongly departs from data above it. It is concluded that the simulation is incomplete at this point, and so a review must be done on the nuclear physics and scintillation light Geant4 packages in order to properly reproduce the detector properties.