Dear experts,
Iam a Fluka beginner and Iam using the DPA-SCO card to evaluate the number of displacements per atom in an accelerator target irradiated with protons. Previous SRIM simulations gave me a dpa value of ~50dpa/year for protons, Fluka simulations gave me a value of ~1000 dpa/year for protons (both values are with respect to the average beam current). So far I thought this huge discrepancy (~factor 50) is due to the fact that SRIM lacks the prediction of nuclear reactions, however these seem not to play a huge role for my simulations.
I have evaluated the dpa with the USRBIN card for the whole region (region binning) of interest (the target) with the following input sequence:
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USRBIN 12. DPA-SCO -21. TAR DPATARPr
USRBIN TAR &
AUXSCORE 2.0 PROTON DPATARPr
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In order to clarify the discrepancy above further I have done a simulation with one single bin inside the region (target), which means I evaluate the whole region and that should lead to the same result as the region binning in principal or? The input sequence part for that is shown in the following lines:
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USRBIN 11. DPA-SCO -21. 5.64 100.5DPAtarPr
USRBIN 0.0 100.0 1. 1.0 &
AUXSCORE 2.0 PROTON DPAtarPr
--------------------------------------------------------------
However, the value I obtain then seems to be much more correct with respect to my SRIM simulation, with ~20dpa/year. It is interesting, that the factor between these values (1000 and 20) is ~50, which is exactly the volume of the region (target). Once the geometry with all regions and bodies is properly defined without any errors (and that is the case) Fluka should automatically take the according volume or? Is it necessary to divide dpa values obtained with a region binning and the DPA-SCO card by the value (without units) of the volume of the corresponding region? If so, why does Fluka not automatically perform that division?
I would be very thankful if someone is able to answer my question or could give me a hint.
Kind regards,
Niklas Ophoven
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Received on Sun Mar 01 2020 - 18:21:37 CET