Date: Thu, 26 May 2016 09:43:13 +0200
Hi Roman,
here are some possible explanations:
1. As to why it is Cartesian grid that yields better fit with OLTARIS
result, perhaps the authors of the paper also used a similar cartesian grid
:)
2. The large deviation near the front is an artifact due to normalization.
Area of Cartesian grid to cylindrical grid is (20*20 cm^2) / (pi*10*10) =
1.27, which also appears to be the ratio of the dose values near the front.
Note that the USRBIN output is per unit volume, therefore you need to
multiply the USRBIN output with the volume to get the values in Gray.
3. Now why the deviation decreases with the depth of the target, the answer
could lie in the transverse profile of the cascade. Towards the end, the
transverse profile of the cascade could be such that it contributes dose to
the Cartesian grid and cylindrical grid in the above mentioned ratio. You
need to explore it further.
Cheers,
Nikhil
NB: The SDUM "CYLINDRICAL" in the line "USRBIN 11. DOSE
-25. 10. 35.CYLINDRICAL" is more than 10 characters!
On Thu, May 26, 2016 at 7:40 AM, Roman Savinov <rsavinov_at_calpoly.edu> wrote:
> Dear FLUKA experts,
>
> I noticed that USRBIN (dose) gives slightly different result depending on
> the grid chosen: Cartesian or Cylindrical.
> the target is a cylinder (r=10, l=30 cm) inside a vacuum void.
> I do understand that when I choose Cartesian grid, some of the void region
> in the corners gets included and affects the result but it doesn't explain
> why deviation is large near the front and decreases with a depth of the
> target:
>
> and more importantly, why it is cartesian grid that yields better fit with
> OLTARIS result?
>
> I am trying to compare FLUKA output with result from this paper:
>
> https://www.researchgate.net/publication/270595107_Shielding_evaluation_for_solar_particle_events_using_MCNPX_PHITS_and_OLTARIS_codes
> specifically fig.9 (bottom right)
>
> here are my scoring cards:
> USRBIN 11. DOSE -25. 10. 35.
> CYLINDRICAL
> USRBIN 0.0 3.7 1. 1. 300. &
> USRBIN 10. DOSE -32. 10. 10.
> 35.CARTESIAN
> USRBIN -10. -10. 3.7 1. 1. 300. &
>
> 3.7 is a thickness of aluminum shield.
>
> thank you,
>
> Roman
>
>
>
>
__________________________________________________________________________
You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?id=acc_info
(image/png attachment: pastedImage.png)