Unable to score photoneutrons following the photonuclear reaction

Hello FLUKA users,
I’m in trouble assessing the photoneutrons created after an electron(18MeV) beam is impinging a tungsten target, i ran this as an example to see the neutron production, I used a USRBIN card when plotting it, it returned a blank green map which indicates a value of 0,
i don’t know where is the problem in my code, whether it is related to biasing or the number of primaries,…, could anyone please take a look on the input example or give me any remarks that will guide me. any remarks on the scoring of neutron by-product of photonuclear reaction are appreciated.
in the hope of getting your remarks, thank you
sept4.inp (1.3 KB)
sept4.flair (2.0 KB)

In the PHOTONUC card, you forgot to indicate the TUNGSTEN material.
Moreover, your BIASING card makes no sense. To bias electron/photon reactions, you should use LAM-BIAS instead (with SDUM blank).