Hello, I’ve got a simple model of a beryllium cylinder with a spherical proton source and then I’m scoring neutrons due to spallation. I’m comparing the FLUKA model with PHITS but I’m not getting agreement between the results so I just wanted to clarify that the source is being defined correctly in…

Hello Emma, Your source definition looks correct to me. But please double-check your geometry definition in the Flair Geometry tab, for me, it contains errors in the blackhole region. A full description of a physical model can be found here: Physics At your energies, it will be using PEANUT. My…

Hello, Thank you for your quick response. Regarding the geometry errors, even though there’s a warning in the geometry tab, there isn’t any error under ‘Input’ or the output tab so I’m not sure what the issue is here [Screen Shot 2024-06-17 at 09.33.58] This is the results I’m getting for the ne…

Hello Emma, Unfortunately, Input will not show this type of error. Although FLUKA accepts it as an input, it will result in unreliable output results. Please redefine your regions until your “Error Found” message disappears: [image] Also, I observe very similar neutron spectra from the latest ve…

Thank you. I have modified the geometry to use boxes instead of planes and it has removed the errors. I am using FLUKA version 4.3.4 which according to the manual includes point-wise neutron treatment. I have included the LOW-PWXS card in the input file so it should be using the point-wise treatment…

For the lethargy plots you can follow instructions from the FLUKA basic lecture course: 11_Scoring_II_2024_INTA.pdf It was done in a beta version of Flair, which can also read some of Phits’ output files. Best wishes, Volodymyr

Hi Volodymyr I’ve followed the instructions to create the plot using FLUKA data but mine looks different to yours, so I’m not sure what I’m doing wrong. Sorry I haven’t really used plotting in Flair at all. be_cyl_monoenergetic_v2-0: Plot #6.pdf (71.5 KB) be_cyl_monoenergetic_v2.flair (3.1 KB) T…

Hi Emma, We are looking into two different things. In USRBDX I was checking flux from the core region into the reflector region, reversed case to yours. Also, the energy range is different. my histogram for neutrons has a range (1e-11, 100) MeV. Cheers, Volodymyr

Hi Volodymyr Ah right, ok, I’m interested in the reflector->core flux but I’ve reversed the direction and changed the energy boundaries. It seems like my results are similar to yours now. I will look into importing the PHITS results. be_cyl_monoenergetic_v2-0: Plot #6.pdf (82.8 KB) Thanks, Emma

Hi Volodymyr Do I need the PHITS output results to be in 1/cm2/MeV/sr/source? Thanks, Emma

Hi Emma, I used single diff. flux over energy integrated over angle in both cases. So units will be 1/cm2/source on the lethargy plot. You are welcome, Volodymyr

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FLUKA comparison with PHITS from proton spallation

Source Definition

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