Re: [fluka-discuss]: Accessing electromagnetic photons

From: Andrea Fontana <andrea.fontana_at_pv.infn.it>
Date: Thu, 6 Jul 2017 13:36:26 +0200

Hi Sourav,
    I see that you have not specified the DEFAULT card in your example:
Quoting from the manual, under PAIRBREM:
"if option DEFAULTS is not present, or is present with SDUM = NEW-DEFA,
both pair production and bremsstrahlung are activated in all materials,
with explicit generation of secondaries of energy ≥ 0 and ≥ 1 MeV,
respectively.
If DEFAULTS is present with SDUM = CALORIMEtry, ICARUS or PRECISIOn,
both pair production and bremsstrahlung are activated in all materials,
with explicit generation of secondaries of energy ≥ 0 and ≥ 300 keV,
respectively.
In any other case, both pair production and bremsstrahlung are activated
in all materials, without explicit generation of secondaries (continuous
loss approximation)".

You can try with DEFAULTS set to precision for instance, but the
lowest energy for explicit photons will be 300 keV.

Andrea



Il 05/07/2017 21:15, Sourav Sarkar ha scritto:
> Hi Andrea,
> Thank you again for your help. I have tried your USDRAW code, however
> I have noticed the issue is still there for my problem.
> USDRAW sees only those bremsstrahlung photons (ICODE=105 or 208) which
> are above the threshold cuts. The photons above the threshold cut go
> into pair production anyway (thus not being final particle), therefore
> I am still missing those photons which are produced with below cut-off
> energy. I checked it by summing up all the final particles energy
> (which in principle should match with injected particle energy) and
> the sum is off by those missing photons.
>
> I think there is no problem with mgdraw routine or USERDUMP settings,
> but with other input parameters. Please let me know if you think
> something else is wrong in my input.
>
> Thank you.
>
> Regards,
> Sourav Sarkar
>
> On Wed, Jul 5, 2017 at 3:13 AM, Andrea Fontana
> <andrea.fontana_at_pv.infn.it <mailto:andrea.fontana_at_pv.infn.it>> wrote:
>
> Hi Sourav,
> I am able to see bremsstrahlung photons with your input file.
> I have slightly modified the USERDUMP card so that you can write
> in ASCII format the output from USDRAW. The COMMON block used is
> GENSTK and, for each bremsstrahlung event (ICODE=105), I have
> added a loop on the variable NP (number of secondaries) and a printout
> of particle ID and energy for each secondary. The output is in the
> file unit 51, in my example: you have to search for events 105
> in the file.
>
> I attach testrun2_af.inp and mgdraw_af.f: with these files
> you can now go on experimenting with the different threshold cuts.
>
> Hope this helps: do not hesitate to write back to the forum in case
> of further questions...
>
> Best regards,
> Andrea
>
> Il 05/07/2017 10:16, Sourav Sarkar ha scritto:
>
> Dear Andrea,
> Thank you for your quick reply. I have commented inline of
> your email.
>
> On Wed, Jul 5, 2017 at 1:45 AM, Andrea Fontana
> <andrea.fontana_at_pv.infn.it <mailto:andrea.fontana_at_pv.infn.it>
> <mailto:andrea.fontana_at_pv.infn.it
> <mailto:andrea.fontana_at_pv.infn.it>>> wrote:
>
> Dear Sourav,
> without seeing your input file, I can only guess:
>
> - is the option PAIRBREM used correctly (see in particular
> Note 2
> in the manual)?
>
> PAIRBREM is focused on the processes for mostly muons and
> hadrons. I have tried both with and without PAIRBREM settings,
> unfortunately there is no difference between the two.
>
> - did you check in USDRAW for ICODE=105 or ICODE=208
> (manual 13.2.13)?
>
> I have tried using USDRAW for ICODE=105 or 208, it is not
> working for me (may be I am using it incorrectly, so still
> working on it). Where does USDRAW access information from
> (FLKSTK/TRACKR/GENSTK)?
>
>
> If you send your input file, I can try to help you.
>
> I have attached my input file with email. I hope it helps you
> understanding my issue.
>
> Kind regards,
> Andrea
>
>
> Il 05/07/2017 07:18, Sourav Sarkar ha scritto:
>
> Dear FLUKA users,
> I am pretty new to FLUKA package which I am using to
> simulate
> high energy hadronic and electromagnetic showers with user
> cut-off (PART-THR and EMFCUT). At the end of shower, I
> require
> to have all the final particles through mgdraw. However I
> noticed that the photons which are generated in
> electromagnetic part of the shower (bremsstrahlung
> radiation)
> and fall below EMFCUT are not accounted in ENDRAW entry.
> P.S. particles below threshold energy are not ranged
> out as my
> cut-off is fairly high.
>
> I am not sure about the reason, which might be one of the
> following:
> 1. Are electrons and positrons assumed to have continuous
> energy deposition (due to radiation) during transport,
> so that
> the secondary photon is not accounted?
>
> 2. The photons which are below the threshold energy
> might not
> be pushed back to main stack from EMFSTK. I get the final
> electrons and positrons in ENDRAW with ICODE=22, so I am
> assuming they are pushed to main stack from EMFSTK through
> TRACKER.
>
> Please let me know what would be possible reason for
> missing
> the photons in my standard collision tape and what is
> the best
> solution for accessing them.
>
> Thank you.
>
> Regards,
> Sourav Sarkar
>
>
> --
> ========================================================================
> Dr. Andrea Fontana tel: +39 0382 987991
> <tel:%2B39%200382%20987991>
> <tel:%2B39%200382%20987991>
> Istituto Nazionale fax: +39 0382 423241
> <tel:%2B39%200382%20423241>
> <tel:%2B39%200382%20423241>
> di Fisica Nucleare
> Sezione di Pavia e-mail:
> andrea.fontana_at_pv.infn.it <mailto:andrea.fontana_at_pv.infn.it>
> <mailto:andrea.fontana_at_pv.infn.it
> <mailto:andrea.fontana_at_pv.infn.it>>
> Via Bassi 6 web :
> www.pv.infn.it/~fontana <http://www.pv.infn.it/%7Efontana>
> <http://www.pv.infn.it/%7Efontana
> <http://www.pv.infn.it/%7Efontana>>
> 27100 PAVIA, Italy
>
> ========================================================================
>
> Thank you.
> Regards,
> Sourav Sarkar
>
>
> --
> ========================================================================
> Dr. Andrea Fontana tel: +39 0382 987991
> <tel:%2B39%200382%20987991>
> Istituto Nazionale fax: +39 0382 423241
> <tel:%2B39%200382%20423241>
> di Fisica Nucleare
> Sezione di Pavia e-mail:
> andrea.fontana_at_pv.infn.it <mailto:andrea.fontana_at_pv.infn.it>
> Via Bassi 6 web :
> www.pv.infn.it/~fontana <http://www.pv.infn.it/%7Efontana>
> 27100 PAVIA, Italy
> ========================================================================
>
>

-- 
========================================================================
Dr. Andrea Fontana                    tel: +39 0382 987991
Istituto Nazionale                    fax: +39 0382 423241
di Fisica Nucleare
Sezione di Pavia                      e-mail: andrea.fontana_at_pv.infn.it
Via Bassi 6                           web   : www.pv.infn.it/~fontana
27100 PAVIA, Italy
========================================================================
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Received on Thu Jul 06 2017 - 14:47:10 CEST

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