DPA calculation: damage-energy score

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1

Hi everyone,
I have a doubt on the damage-energy (MT=444) score tally units for dpa calculation. The quantity we should obtain tallying the damage energy, calculated by NJOY, is the damage energy production in units of [eV-barn] but the documentation says we should get directly something in units of eV. Can somebody clarify on this?
Thank you.
Lorenzo

2

Hi @lorenzo,

You are correct that the information from NJOY for damage energy is given in units of [eV-b]. This is the microscopic cross section value for damage energy of an isotope. Once multiplied by the number densities of a material, we can use the resulting macroscopic cross section (in units of [eV / cm]) to produce a reaction rate in units of [eV / source-particle].

You can see a similar situation for heating in the theory section. of the OpenMC documentation.

I hope this helps.

-Patrick

3

Hi @pshriwise;
Thank you for the prompt answer. If I got right, from NJOY we get [eV-barn] but from the damage-energy tally we get [eV-source]. The conversion is done by the tally itself, is that correct?
Lorenzo

4

Hi @lorenzo, correct. The conversion of these units happens during the simulation itself.

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