If the beam intensity is constant (this is naturally the assumption in raw results, which are normalized to the number of primaries in both cases), then in your second simulation the power should be distributed in an area four times larger, thus the dose (i.e. per unit mass which scales to area) should be expected to scale accordingly.
-M
From: owner-fluka-discuss_at_mi.infn.it <owner-fluka-discuss_at_mi.infn.it> on behalf of Ševčik Aleksandras <aleksandras.sevcik_at_ktu.edu>
Sent: Wednesday, February 12, 2020 11:40 AM
To: fluka-discuss_at_fluka.org <fluka-discuss_at_fluka.org>
Subject: [fluka-discuss]: kerma calculation / impact from beam size
Hello,
I’m struggling to understand why the beam size/shape affects my dose calculations. I have made usrbrin 1x1x30 cm detector along Z axis and simulated 1 MeV photon beam. If the beam size is equal to 1x1 cm rectangular shape, the value is exactly as expected, ~4.47e-12 Gy. However, if I increase the size of the beam, for example, to 2x2 cm, the value proportionally decreases, in this case four times. I don’t get why the increased beam size area affects the dose value in the detector. It is probably related to the way how I am plotting them? Could maybe someone to point out what I am missing? I am getting the values by plotting them as 1-D projection along Z axis
Regards
Alex
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Received on Thu Feb 13 2020 - 03:22:05 CET