Unable to score photoneutrons following the photonuclear reaction

Scoring
1

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)

s1
s11210×513 95 KB

2

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).