Re: Question: How to stop neutron transport below 1 MeV and beyond 20 MeV

Dear User,
Do you really want to stop the neutron transport beyond 20 MeV? If I have
understood your set-up, in case you stop the higher energies neutron you
will use the neutrons that slowing down will have energies in the 1-20 MeV
region which in principle can be detected by your CR-39 detectors.
Cheers,
Andrea

> Dear Fluka Experts,
>
> Many many thanks for helping me with my previous question on LOW-MAT.
>
> I am modelling a simplified snout for proton therapy. Outside the snout, I
> have placed a water phantom and inside the phantom I have placed several
> CR-39 Plastic Nuclear track detectors. These detectors are tissue
> equivalent and are placed at various angles and various distances from
> isocenter. I want to calculate the dose equivalent at different locations
> using these detectors due to the neutrons created in the snout and in the
> phantom.
>
> My question: CR-39 Detectors are sensitive to neutrons of about 1-20 MeV.
> So I want to measure dose equivalent only from neutrons of 1to 20 MeV.
> According to manual, the low energy neutron has a range of 1e-14 GeV to
> 0.02 GeV and after that fluka hadronic model takes over. But I want the
> dose equivalent only from* 1-20MeV* of neutrons. If I use PART-THR card
> for
> neutron cut-off I can stop neutron transporting with a energy lower than 1
> MeV but how can I stop the neutron transport beyon
d 20 MeV.
>
> To check that neutron transportation is stopped below 1MeV, I plotted
> fluence graph for 226 MeV proton using USRCOL card which I attached here
> with. But I dont know how to stop neutrons beyond 20 MeV at the same time.
>
>
> Please help.
>
>
> Thanks
> Mohammad Rafiqul Islam
> PhD student, Oklahoma State University
> USA
>
Received on Thu Apr 05 2012 - 08:06:22 CEST