Gamma source from neutron activation using df

Separate section for discussion on gamma transport
Post Reply
Posts: 8
Joined: Wed Aug 01, 2018 7:53 am
Security question 1: No
Security question 2: 93
Location: Loviisa NPP

Gamma source from neutron activation using df

Post by kaartinen » Thu Aug 22, 2019 9:28 am


is there any way to use df in neutron calculation and then use those points in space as source points for a separate gamma calculation?
This way I could get proper distribution of "activation"

I tried the following detector to score capture points

Code: Select all

det 1 n dr -2 steel df hits 1
And this on the gamma simulations

Code: Select all

src se 1.3 sf hits
When tried with neutron source it worked fine but it didnt work with photon source. I am not sure how sf works but I would like to only extract positions from it to sample gamma photons such as Co-60 gammas from activation

EDIT: If I understood right, when I try to run it with the file I got from neutron simulation, it will use the same exact directions and energies also. Is there a way to tell Serpent only to use positions?

User avatar
Jaakko Leppänen
Site Admin
Posts: 2441
Joined: Thu Mar 18, 2010 10:43 pm
Security question 2: 0
Location: Espoo, Finland

Re: Gamma source from neutron activation using df

Post by Jaakko Leppänen » Sun Aug 25, 2019 10:05 pm

So if I understood correctly, you would like to get a point-wise Co-60 activation gamma source based on neutrons hitting the material?

I don't think It's physically possible to get the activation gammas from point-wise neutron distribution without some additional physics. This would require sampling both the activation reaction and the decay of the resulting Co-60 nucleus.

The df option works by writing the scored events into a file. This was implemented mainly for surface current detectors, to obtain surface sources. In your case what is written in the file are the coordinates, direction, energy, weight and time of colliding neutrons, and the dr entry which defines the response plays no role.

So in order to get the activation source, you would need to take the neutron collisions from the file, sample the reactions that produce Co-60, and then sample the decay time and the parameters of the emitted photons. I guess this would be possible by some post-processing script, but it is not a straightforward task.
- Jaakko

Post Reply