## Eddington Factors Calculation in Serpent

Discussion on physics, models and calculation methods

### Eddington Factors Calculation in Serpent

Good Day Everybody,

I wanted to ask about if Serpent has a tally for calculating the required parameters to calculate Eddington Factors? I found that it was done before in Serpent 1.19 by Andrew Hall of UM. Is this capability found in Serpent right now for Version 2.1.30? thank you very much!
Ramzy1990

Posts: 10
Joined: Mon Oct 22, 2018 5:59 pm

### Re: Eddington Factors Calculation in Serpent

Hi,

I'm not entirely sure what is needed for the calculation of Eddington factors, but I understand it has something to do with weighting tallied fluxes with the angular direction. Serpent has the capability to add directional/angular weighting to detector tallies: http://serpent.vtt.fi/mediawiki/index.php/Input_syntax_manual#det_dir

Perhaps you can say if that is enough or if something additional is needed.

-Ville
Ville Valtavirta

Posts: 308
Joined: Fri Sep 07, 2012 1:43 pm

### Re: Eddington Factors Calculation in Serpent

Hello Dr. Ville,

I am not entirely sure really, but the following website http://montecarlo.vtt.fi/mtg/2015_Knoxville/Andrew_Hall.pdf has some more information. What I understood is that during the scoring of the flux in Serpent, I will have to add more tallies that additionally weight the angular flux by direction. Would that be possible for example by including the direction vector in the detectors? Would I need 9 different oriented vectors to get the required matrix mentioned in the above file?
Ramzy1990

Posts: 10
Joined: Mon Oct 22, 2018 5:59 pm

### Re: Eddington Factors Calculation in Serpent

The use of the direction vector in the detector might be enough for getting the diagonal terms in the tensor.

I don't know how exactly Andrew tallied the off-diagonal terms.

-Ville
Ville Valtavirta

Posts: 308
Joined: Fri Sep 07, 2012 1:43 pm

### Re: Eddington Factors Calculation in Serpent

Ah yes I did not notice that a vector for xy might be similar to yx for e.g.! So the diagonal terms would use vectors of the forms (1 0 0) (0 1 0) (0 0 1) in the Detector direction vector. I will look into it soon if God will and I will keep you posted too sir.

Thank you very much,

Ramzy
Ramzy1990

Posts: 10
Joined: Mon Oct 22, 2018 5:59 pm