--
Dr. Daria Boscolo
Biophysics / Biophysik
Phone / Telefon: +49 6159 71 1650
Fax: +49 6159 71 2106
Mail: d.boscolo_at_gsi.de
Location: SB2.3.188
GSI Helmholtzzentrum für Schwerionenforschung GmbH
Planckstraße 1, 64291 Darmstadt, Germany, www.gsi.de
________________________________________
Da: Giuseppe Battistoni <giuseppe.battistoni_at_mi.infn.it>
Inviato: venerdì 14 gennaio 2022 14:57:18
A: Boscolo, Daria Dr.; Santana, Mario; fluka-discuss_at_fluka.org
Oggetto: Re: [fluka-discuss]: I: momentum spread with source routine
Oh yes! It is true that the energy variables FLUKA in the stack, TKEFLK
(NPFLKA) is always in total energy and so also the momentum.
Maybe you will obtain a better agreement if you express the mass not in
GeV/c^2 but in units of atomic mass, for instance you can write:
PMOSPR= (WHASOU(5) * AM (IONID)/AMUC12) /2.355
AMUC12 is a parameter containing 0.931... GeV/c^2
Even better if you write:
PMOSPR= (WHASOU(5) * AM (IONID)/AMUC12) /S2FWHM
S2FWHM is the 2.355 but in double precision with many more decimals
Ciao
Giuseppe
On 14/01/2022 14:45, Boscolo, Daria Dr. wrote:
> Hi Mario,
>
> many thanks. I tried to test the new version but it sims to me that there is still a problem with the units.
> Is it possible that while in the beam card the momentum spread has to be given in GeV/c/u (at least for heavy ions) in the source routine it is interpreted as GeV/c? When I multiply my momentum spread by the atomic mass then I get very similar results. Am I correct?
>
>
> The updated user routine now looks like that:
>
> * | Particle momentum
> CALL FLNRRN(RGAUS_MO)
> PMOSPR= (WHASOU(5) * AM (IONID)) /2.355
> PMOFLK (NPFLKA) = PBEAM + ( PMOSPR * RGAUS_MO )
>
> * | Kinetic energy of the particle (GeV)
> TKEFLK (NPFLKA) = SQRT ( PMOFLK (NPFLKA)**2 + AM (IONID)**2 )
> & - AM (IONID)
>
> many thanks,
> Best regards,
> Daria
>
>
> --
> Dr. Daria Boscolo
> Biophysics / Biophysik
>
> Phone / Telefon: +49 6159 71 1650
> Fax: +49 6159 71 2106
> Mail: d.boscolo_at_gsi.de
> Location: SB2.3.188
>
> GSI Helmholtzzentrum für Schwerionenforschung GmbH
> Planckstraße 1, 64291 Darmstadt, Germany, www.gsi.de
>
> ________________________________________
> Da: Santana, Mario <msantana_at_slac.stanford.edu>
> Inviato: giovedì 13 gennaio 2022 18:45:15
> A: Boscolo, Daria Dr.; fluka-discuss_at_fluka.org; giuseppe.battistoni_at_mi.infn.it
> Oggetto: Re: [fluka-discuss]: I: momentum spread with source routine
>
> PMOFLK (NPFLKA) = PBEAM*(ONEONE+PMOSPR*RGAUS_MO)
>
> -->
>
> PMOFLK (NPFLKA) = PBEAM + ( PMOSPR * RGAUS_MO )
>
>
> Isn't it?
>
>
>
> ________________________________
> From: owner-fluka-discuss_at_mi.infn.it <owner-fluka-discuss_at_mi.infn.it> on behalf of Boscolo, Daria Dr. <D.Boscolo_at_gsi.de>
> Sent: Thursday, January 13, 2022 3:08 AM
> To: fluka-discuss_at_fluka.org <fluka-discuss_at_fluka.org>; giuseppe.battistoni_at_mi.infn.it <giuseppe.battistoni_at_mi.infn.it>
> Subject: Re: [fluka-discuss]: I: momentum spread with source routine
>
> Hi Giuseppe,
>
> many thanks for the help.
> Unfortunately, inverting the calculation of the kinetic energy and momentum did not help and I get the same result as before.
> Just for consistency I attach here the new source routine and the plot with the two spectra.
>
> Ciao,
> Daria
>
> --
> Dr. Daria Boscolo
> Biophysics / Biophysik
>
> Phone / Telefon: +49 6159 71 1650
> Fax: +49 6159 71 2106
> Mail: d.boscolo_at_gsi.de
> Location: SB2.3.188
>
> GSI Helmholtzzentrum für Schwerionenforschung GmbH
> Planckstraße 1, 64291 Darmstadt, Germany, www.gsi.de
>
> ________________________________________
> Da: Giuseppe Battistoni <giuseppe.battistoni_at_mi.infn.it>
> Inviato: mercoledì 12 gennaio 2022 18:06:16
> A: Boscolo, Daria Dr.; fluka-discuss_at_fluka.org
> Oggetto: Re: [fluka-discuss]: I: momentum spread with source routine
>
> Hi Daria
>
> I see that in the source routine you write:
>
>
> * | Kinetic energy of the particle (GeV)
> TKEFLK (NPFLKA) = SQRT ( PMOFLK (NPFLKA)**2 + AM (IONID)**2 )
> & - AM (IONID)
> * | Particle momentum
> CALL FLNRRN(RGAUS_MO)
> PMOSPR=WHASOU(5)/2.355
> PMOFLK (NPFLKA) = PBEAM*(ONEONE+PMOSPR*RGAUS_MO)
> *
>
> So you first calculate the kinetic energy and after that you fluctuate
> the momentum. This could be inconsistent.
>
> Try instead to write:
>
> * | Particle momentum
> CALL FLNRRN(RGAUS_MO)
> PMOSPR=WHASOU(5)/2.355
> PMOFLK (NPFLKA) = PBEAM*(ONEONE+PMOSPR*RGAUS_MO)
> * | Kinetic energy of the particle (GeV)
> TKEFLK (NPFLKA) = SQRT ( PMOFLK (NPFLKA)**2 + AM (IONID)**2 )
> & - AM (IONID)
>
> So you calculate a kinetic energy consistent with the fluctuated momentum.
>
> I do not know if this is the solution, but I invite you to test it.
>
> Ciao
> Giuseppe
>
> On 12/01/2022 11:31, Boscolo, Daria Dr. wrote:
>> Dear FLUKA experts,
>>
>> I am trying to implement a gaussian momentum spread with the source routine as it is in the beam card.
>> To do that I followed the indication given in a previous discussion in this forum:
>> http://www.fluka.org/web_archive/earchive/new-fluka-discuss/18392.html
>>
>> However, the distribution I obtain does not match with the one I see when using the beam card: the two results differ of about a 30% on the momentum spread sigma.
>>
>> I attach here a plot of the two energy spectra together with the two input files and the source routine I am using.
>>
>> Many thanks for the help,
>> Best regards,
>> Daria
>>
>> --
>> Dr. Daria Boscolo
>> Biophysics / Biophysik
>>
>> Phone / Telefon: +49 6159 71 1650
>> Fax: +49 6159 71 2106
>> Mail: d.boscolo_at_gsi.de
>> Location: SB2.3.188
>>
>> GSI Helmholtzzentrum für Schwerionenforschung GmbH
>> Planckstraße 1, 64291 Darmstadt, Germany, www.gsi.de
> --
> INFN Sezione di Milano
> via Celoria 16, 20133 Milano
> tel: +39 02 50317307
>
>
--
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via Celoria 16, 20133 Milano
tel: +39 02 50317307
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Received on Fri Jan 14 2022 - 16:31:54 CET
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