optical photon production

Dear Fluka users,

I am trying to simulate the production of scintillation photons from a BC400 scintillator immerse in water and irradiated by a proton beam. Since this is my first simulation with optical photons I (more or less) followed the example in section 12.2.4 of the manual, but apparently something is missing or wrong in my input, because there is no light production or at least I cannot detect any optical photon from usrbin or any other scoring card. Could anyone help? The input file is attached.

Many thanks
Francesca

P.S.: So far I kept the Cherenkov light generation off, but once the simulation works I am going to activate that too.

Dr Francesca Fiorini
Gray Institute for Radiation Oncology and Biology
Old Road Campus Research Building
Off Roosevelt Drive
University of Oxford
Oxford, OX3 7DQ
UK