JETPEAK is a comprehensive stationary-state database and a work environment for JET diagnostics data, processed data and simulations suitable for a wide variety of analytical tasks. It enables systematic modelling and efficient interpretation of synthetic neutron diagnostics and validation of fast particle and fusion product calculations. We present a processing chain connecting the ASCOT orbit following code and AFSI fusion source simulator Monte-Carlo codes, providing synthetic diagnostics data for systematic comparison with measured data and model validation. The ASCOT code defines the reactant distribution functions and the additional AFSI module creates fusion products as 4D (R, z, E, pitch) distributions, which serve as input for synthetic diagnostics calculations. In this contribution we present synthetic neutron emission rates for the JET neutron camera lines of sight. First results show a fair agreement of the synthetic camera results with the horizontal JET neutron cameras and systematic differences, which are not understood, between the ratios of neutron emission measurements and modelled for the vertical and horizontal cameras.