Scoring cards for fluence to dose conversion factors

Dear Expert,

I am lacking to understand a conceptual aspect.

  1. When we use fluence to dose conversion factors to estimate dose, which type of fluence should be scored inside the target region? Is it one way scoring of USRBDX or USRTRACK ? In this case, I am using my own set of fluence to dose conversion factors and the output fluence will be converted to dose using a separate MATLAB based program.

  2. In the above context, when we use AUXSCORE, with photon as “Part” and ERT74 as “set”, what should we use as “Type” ?

Regards,
Riya

Dear Riya,

  1. The to activate the fluence to ambient dose equivalent / effective dose conversion you need to score DOSE-EQ. This type is “particle” is available on each type of scoring (USRBIN, USRBDX, USRTRACK, etc.).

  2. By default (without an AUXSCORE card) the conversion factors to ambient dose equivalent (AMB74) is used. If you want to change it to a different one. You need to add an AUXSCORE card:

    • Part: Left empty
    • Set: The desired conversion factor
    • Type: Type of the scoring you want the AUXSCORE card apply to
    • Det: Name of the detector(s) to apply the AUXSCORE card

    See the 3rd example for the AUXSCORE card: https://flukafiles.web.cern.ch/flukafiles/manual/AUXSCORE.html

  3. If you want use a other conversion factors, you can program and apply it to any fluence scorings with the fluscw.f user routine.

Cheers,
David

Thank you David @horvathd , I have few more doubts.

  1. The conversion factors are fixed set of data (the list goes as energy and corresponding dose per fluence). These factors are independent of the type of scoring card (USRBIN, USRBDX, USRTRACK). So if we want to estimate effective dose using rotational conversion factor (ERT 74) and if we use USRBIN or USRBDX or USRTRACK, will they give same result ? For example, please see the attached image, please check if all the fields are correctly filled or not.

  2. I have gone through the default fluscw.f user routine provided in fluka library. I can see that there are some functions for defining particle position, KE, weight etc. These information we usually give in source.f routine. So, if I use fluscw.f user routine, then do I have to give particle information here ? Does this mean that in this case we do not need source.f separately ? or can we use source.f and fluscw.f at the same time? If yes, then what should we keep Txx,yy,zz etc in fluscw.f ? Will these information be automatically read from source.f ?

  3. Where do we have to give the array of energy and conversion factors in fluscw.f ? Is there any sample file available ?

Thanks,
Riya

Dear Riya,

  1. The different type of scorings usually don’t give the same result numerically (except an unnormalized USRTRACK and USRBIN with Type: Region), because a different method of scoring, but the results should be comparable.

    Your input is missing a AUXSCORE card for the USRTRACK scoring. Plus, since you selected Part: PHOTON on these cards, the scoring will only have the effective dose coming only from photons. The contribution of other particles will be disregarded.

    Note: The USRBIN scoring with Type: Region is NOT normalized with the volume (since FLUKA doesn’t know the volume of the regions) so the results would be in [pSv * cm^3].

  2. The input parameters in fluscw.f are there to be able to apply a different conversion factor FLUSCW (the only output of the script) to different particles, based on type, energy, location, direction, region, etc. These parameter are provided by FLUKA to the routine, based on the current scoring event.

    It is possible to use both source.f and fluscw.f at the same time, as source.f will be used to generate the primary particles, and fluscw.f will be used at scoring.

  3. I’m not aware if there is a simple way or an example for fluscw.f, where you can simply provide the conversion factors. Is there anything specific you would like to implement?

Cheers,
David

1 Like

Thanks a lot David @horvathd,

Yes, I missed the AUXSCORE for USRTRACK.

So, if I keep it blank in Part (instead of writing it as Photon), then effective dose will be from all particle, that means dose conversion factors for all particles will be considered. Am I right?

Also, the conversion factors provided in FLUKA are from ICRP 74. My intention was to use conversion factors from the latest ICRP 116. I used to score USRTRACK and then I collect the fluence data. Then I externally couple them with ICRP 116 conversion factors by using linear interpolation. But since this mapping can also be done using fluscw.f, I thought it will be better if I could use that source routine.

Regards,
Riya

Dear Riya,

Yes, if you keep Part empty, then all particles which have the conversion factor available (neutrons, protons, charged pions, muons, photons and electrons) will be taken into account.

The ICRP 116 conversion factors may be implemented natively in FLUKA later on, but currently there isn’t a timeline for it. Since you already have a Matlab program to do the conversion, it should be possible to implement it in fluscw.f using Fortran.

Cheers,
David

Thank you. The concept is now clear to me.

Regards,
Riya

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