Dear Alberto,
Thank you for your quick response. I have attached here the mgdrawBDX that I
used where I have collected the position coordinate, direction cosines,
energy and weight. I have to use mgdrawBDX since I am using a two-step
simulation.
In the 1st simulation, I scored photon distribution using mgdrawBDX (the
position coordinate, direction cosines, energy and weight) and in the 2nd
simulation, I used these data as input (by reading a txt file containing
outputs from mgdrawBDX) to estimate dose.
In the 1st simulation, I have added USRBDX card, to verify the correlation
between the outputs from USRBDX and mgdrawBDX where I found the previous
discrepancy.
It will be very helpful, if you can guide me on this.
-----Original Message-----
From: Fasso, Alberto [mailto:fasso_at_slac.stanford.edu]
Sent: 09 September 2020 13:15
To: Riya Dey <riyadey_at_barc.gov.in>; fluka-discuss_at_fluka.org
Subject: Re: [fluka-discuss]: comparison of photon fluence from mgdrawBDX
and USRBDX
Dear Riya Dey,
the ratio between the USRBDX results and that obtained by you with mgdraw is
nearly exactly 2. Therefore, it is obvious that with mgdraw you have not
scored fluence, but current.
See any of the FLUKA course lectures:
"In an isotropic field can be easily seen that on a flat surface J = Ö/2"
Indeed, did you take into account the cosine of the crossing angle? It is
not an easy task, especially for grazing particles crossing the boundary.
One important lesson you should learn is to trust the built-in FLUKA scoring
algorithms, which are nearly always much better than what you can try to do
by yourself with mgdraw or other user functions
Alberto
________________________________________
From: owner-fluka-discuss_at_mi.infn.it <owner-fluka-discuss_at_mi.infn.it> on
behalf of Riya Dey <riyadey_at_barc.gov.in>
Sent: Wednesday, September 9, 2020 5:54 AM
To: fluka-discuss_at_fluka.org
Subject: [fluka-discuss]: comparison of photon fluence from mgdrawBDX and
USRBDX
Dear FLUKA experts,
In a simulation, mgdrawBDX has been used to obtain photon distribution from
void to target. The total no of data point obtained is 243341 for 5E+9
primaries (no of history = 1E+8, spawn = 10, cycle = 5). Then from this
information, photon fluence is 4.86682E-5 particle/primary.
At the same time I have used USRBDX card with one way scoring from void to
target and fluence is ( --> (Part/pr) 9.6862677E-05 +/-
0.3224583 % ).
From my understanding, these two numbers should match.
Can you please guide me in this matter ?
Thanks and Regards
~~~~~~~~~~~~~~~~~~~~~~~~~
Riya Dey
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Received on Wed Sep 09 2020 - 10:02:54 CEST