- Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ] [ by messages with attachments ]

From: Paola Sala <paola.sala_at_mi.infn.it>

Date: Mon, 2 Mar 2020 08:30:11 +0100

Dear Niklas,

if the binning is by region, the result is not "displacements per atom",

it is DPA*Volume. It means, that the code correctly applies the

normalization for density, not the one for total mass.

I take the occasion to rectify my previous answer: for cartesian/r-phi-z

binning the result is normalized per cm^3 for most quantities, it is

directly in DPA for DPA-Scoring.

Both methods are correct, the scoringf by region means that you'll have to

insert a normalization offline.

Scoring with a "grid" binning gives also the possibility to look at the

space distribution of DPAs within your scoring region.

Hope this helps

Paola

*> Dear Paola,
*

*>
*

*> thanks for your answer!
*

*>
*

*> If Fluka does not calculate the volume, how can it then know the proper
*

*> amount of atoms it needs to relate the number of displacements to? Is
*

*> there a need to further process a value from the region binning?
*

*> I want to have an average dpa value for the whole region (target). What
*

*> would be the "correct" value then in your point of view, that one obtained
*

*> by region binning or by binning with a bin number of 1 (which represents
*

*> the whole target)?
*

*>
*

*> Kind regards,
*

*> Niklas
*

*> ________________________________________
*

*> Von: Paola Sala [paola.sala_at_mi.infn.it]
*

*> Gesendet: Sonntag, 1. März 2020 21:25
*

*> An: Ophoven, Niklas
*

*> Cc: fluka-discuss_at_fluka.org
*

*> Betreff: Re: [fluka-discuss]: DPA-SCO card
*

*>
*

*> Hello
*

*> Results from USRBIN by region are not normalized. Fluka does not calculate
*

*> the volume of each region. On the contrary, results from cartesian or
*

*> r-phi-z binning are normalized per cm^3, since the bin dimensions are
*

*> known to the code.
*

*> Regards
*

*> Paola
*

*>> 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:
*

*>>
*

*>> --------------------------------------------------------------
*

*>>
*

*>> USRBIN 12. DPA-SCO -21. TAR
*

*>> DPATARPr
*

*>> USRBIN TAR
*

*>> &
*

*>> AUXSCORE 2.0 PROTON
*

*>> DPATARPr
*

*>>
*

*>> --------------------------------------------------------------
*

*>>
*

*>> 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:
*

*>>
*

*>> --------------------------------------------------------------
*

*>>
*

*>> 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
*

*>>
*

*>>
*

*>>
*

*>>
*

*>>
*

*>>
*

*>> ------------------------------------------------------------------------------------------------
*

*>> ------------------------------------------------------------------------------------------------
*

*>> Forschungszentrum Juelich GmbH
*

*>> 52425 Juelich
*

*>> Sitz der Gesellschaft: Juelich
*

*>> Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498
*

*>> Vorsitzender des Aufsichtsrats: MinDir Volker Rieke
*

*>> Geschaeftsfuehrung: Prof. Dr.-Ing. Wolfgang Marquardt (Vorsitzender),
*

*>> Karsten Beneke (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt,
*

*>> Prof. Dr. Sebastian M. Schmidt
*

*>> ------------------------------------------------------------------------------------------------
*

*>> ------------------------------------------------------------------------------------------------
*

*>>
*

*>>
*

*>
*

*>
*

*> Paola Sala
*

*> INFN Milano
*

*> tel. Milano +39-0250317374
*

*> tel. CERN +41-227679148
*

*>
*

*>
*

*>
*

Paola Sala

INFN Milano

tel. Milano +39-0250317374

tel. CERN +41-227679148

__________________________________________________________________________

You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?id=acc_info

Received on Mon Mar 02 2020 - 10:19:33 CET

Date: Mon, 2 Mar 2020 08:30:11 +0100

Dear Niklas,

if the binning is by region, the result is not "displacements per atom",

it is DPA*Volume. It means, that the code correctly applies the

normalization for density, not the one for total mass.

I take the occasion to rectify my previous answer: for cartesian/r-phi-z

binning the result is normalized per cm^3 for most quantities, it is

directly in DPA for DPA-Scoring.

Both methods are correct, the scoringf by region means that you'll have to

insert a normalization offline.

Scoring with a "grid" binning gives also the possibility to look at the

space distribution of DPAs within your scoring region.

Hope this helps

Paola

Paola Sala

INFN Milano

tel. Milano +39-0250317374

tel. CERN +41-227679148

__________________________________________________________________________

You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?id=acc_info

Received on Mon Mar 02 2020 - 10:19:33 CET

*
This archive was generated by hypermail 2.3.0
: Mon Mar 02 2020 - 10:19:38 CET
*