H*(10) Scoring Differences

Scoring
1

Dear FLUKA experts,

I’m trying to calculate the ambient dose equivalent H*(10) at a specific point in space using a neutron source. To achieve this, I defined a sphere (0.5 cm radius) centered at the point of interest and applied three different scoring methods:

  1. USRBDX - Scoring DOSE-EQ from inside the sphere to the external void (area defined).
  2. USRBDX - Scoring neutron fluence from inside the sphere to the external void (area defined), with AUXSCORE - AMB74 applied.
  3. USRTRACK - Scoring neutron fluence inside the sphere volume (volume specified).

I ran 1e+8 primaries in 5 spawns.

Issue:
I expected similar values from the three methods, but instead, they differ by orders of magnitude. I need help understanding the potential differences between these scoring techniques and their respective units of measurement.

Additionally, to extract values from AUXSCORE, I typically select the ASCII output. Are there alternative ways to retrieve this data? In a previous post, I read that the sum.lis file’s first lines can be used since the header is preformatted, and the actual unit of measurement is pSv/cm. However, the header presents two values: one in part/cm²/pr and another in part/pr. Which of these corresponds to pSv/pr?

Thanks a lot for your invaluable help!
Best regards,
Antonella

1 Like
3

Hi Antonella,
could you provide the flair file you used ?
Cheers,
Markus

4

Already based on your description:
The AUXSCORE card will only apply the set of fluence-dose conversion coefficients (AMB74, etc.) when using DOSE-EQ in the USRxxx card.

So in the first case, you score DOSE-EQ with AMB74 conversion coefficients and the output is in units pSv/pr.
For the other two cases you are scoring neutron fluence, without applying any fluence-dose conversion coefficients. Units would be part/cm2/prim or part/cm/prim, depending on if you provide the volume (for USRTRACK) or area (for USRBDX)

5

Hi Markus,
thank you very much for your answer!
Here are the input files:

ICRU_sphere_dose.flair (5.5 KB)
ICRU_sphere_dose.inp (2.2 KB)
AmBe_source_newgen.f (23.9 KB)
AmBe_spec.txt (2.0 KB)

However, I perfectly understood my mistake. I believed that AUXSCORE was performing a ‘bin-wise multiplication’ of the neutron fluence and conversion coefficient spectra.

Cheers,
Antonella

6

OK, then we may close this case here :slight_smile:

1 Like