Where to find the systematic error

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1

Dear FLUKA experts,

I am using FLUKA to simulate the electron deposited energy and dose in a titanium foil, named “window” in the attached files.
tiwindow.flair (11.3 KB)
tiwindow.inp (10.1 KB)
I want to estimate the uncertainty (total error) of the dose or energy, while from the last step it seems that we can only get the statistic error. Could you please advise where I can find the systematic error?

Thanks a lot.

Best,
Xi

3

Dear @xili,

please give a look at those slides, in particular pages 32-33.

A non-exhaustive list of systematic errors is reported: most of these errors depend on how good (or bad) you know the geometry, the material composition…
A variation of those parameters and examination of the change in the desired observed result is a way to estimate the systematic error.
Otherwise, you can make some conservative assumptions and provide estimations with some safety margins.

Finally, there are systematic errors due to the physics model implementation. In that case, there are no knobs on the user side, since physical models in FLUKA are fully integrated. The uncertainty size would be driven by experimental data error.

Please let us know if you have any additional questions.

Best regards, Luigi

4

Thank you Luigi for your great reply.

I have taken a look at the slides. Except for the material, geometry, etc, Seems that the physical models, cross section uncertainty and transport algorithm contribute to the systematic error. Since I used the built-in models in my flair file, temporally let us consider the error from physical models, cross section uncertainty and transport algorithm, Could you please advice where to find the systematic error in the simulated files or how to estimate it? Thanks.

Best,
Xi

5

Dear @xili ,

as explained in the previous email, no way to extract the systematic error related to physics models from the simulation.
You can perform benchmarks with respect to available data, as in the example in page 41 of this slides. This case is for an 1.75 MeV electron beam on a thin copper foil, which is akin to your setup.

Hope this can help.

Cheers Luigi

6

Thank you Luigi,

That makes sense to me. I thought there already have some systematic error acquired in FLUKA models from some former comparisons.

Best,
Xi