Date: Wed, 27 May 2020 10:17:26 +0200
Dear Julien
there are two typos in your mgdraw code: the line
& TKI(ip), CXR(ip), CXR(ip), CXR(ip), WEI(IP)
writes three times the x-cosine.
I used your code with a simple setup, monoenergetic protons along z, and
I do not see any problem. Please find attached the distribution of the
three direction cosines of alpha particles in the two cases. The "cz" ,
cosine along z, gives the zenith angle wrt beam, and is forward peaked as
it should be from momentum conservation. The other two cosines give the
azimutal angle (plotted) that is is flat (within my low statistics).
I attach also the data files
Regards
Paola
> Dear Paola,>>
>
> First I would like to thank you for your help.
>
> For this reaction, I obtain this 2 plots for primaries and secondaries
> alphas (those from fast stage reaction and secondaries from break up of
> Be).
> It is really strange, I have a strong anisotropy for primary alphas (plots
> in attachment png files).
>
> It looks like a problem of angle distribution. I never saw that in a MC
> code. Have you got an idea?
> And moreover, the incident protons are not monoenergetic (read from
> source.f with energies from 1 to 40MeV with divergence of 700mrad).
>
> Sorry but I have also some questions about cross sections. We want to
> publish scientific paper with comparsion between experimental and Fluka
> simulation results but we have to have access to cross sections. Even if
> it is not an easy way, can we obtain that with simulations?
>
> And about cross sections, we work in plasma. Have we got a mean to
> implement cross sections in plasma medium (because cross sections in FLUKA
> are calculated at ambiant temperature I guess).
>
> Thank you again
> Julien
>
> ----- Mail original -----
> De: "Answers" <answers_at_pcfluka.mi.infn.it>
> À: "Julien Bonvalet" <julien.bonvalet_at_u-bordeaux.fr>
> Cc: "fluka-discuss" <fluka-discuss_at_fluka.org>
> Envoyé: Lundi 25 Mai 2020 09:17:40
> Objet: Re: [fluka-discuss]: Difference between FHEAVY and GENSTK
>
> Dear Julien,
> In fluka, the reaction you describe can proceed through different paths,
> also depending on proton energy:
> - There can be alpha emission in the fast stage of the reaction
> (preequilibrium) through the coalescence mechanism, followed by break-up
> of the Beryllium nucleus
> - There can be direct break-up of the compound nucleus into
> alpha+berillyum, followed instantaneously by berillyum disintegration
>
> In both cases, the 8B can be its ground or excited state.
>
> I wrote break-up, not evaporation, because Fluka uses fermi break-up for
> A<=16.
>
> Alphas from the fast stage are stored in GENSTCK
> Alphas from break-up are in FHEAVY
>
> Be sure to use the fluka2020 version, which includes an advanced
> descriprion of this specific reaction.
>
> Hope this helps
> Paola
>
>
> On Thu, 21 May 2020, Julien Bonvalet wrote:
>
>> Hi Fluka users,
>>
>> I have a question about this 2 stacks.
>> I study pB fusion and alphas created wtih mgdraw routines. I would like
>> to
>> see the different ways to produce alphas in 11B(p,2alphas)alpha. The 2
>> alphas coming from 8Be evaporation.
>>
>> In mgdraw.f I did that:
>> ENTRY USDRAW ( ICODE, MREG, XSCO, YSCO, ZSCO )
>> IF ( UDFIRST ) THEN
>> UDFIRST = .FALSE.
>> OPEN ( UNIT = 81, FILE = "collalfa1", STATUS = 'NEW')
>> OPEN ( UNIT = 82, FILE = "collalfa2", STATUS = 'NEW')
>> ENDIF
>> do 20 ip = 1, NP
>> IF (KPART(ip) .EQ. -6) THEN
>> WRITE(81,*) JTRACK, ETRACK-AM(JTRACK), XSCO, YSCO, ZSCO,
>> & TKI(ip), CXR(ip), CXR(ip), CXR(ip), WEI(IP)
>> ENDIF
>> 20 continue
>> do 30 ip=1,NPHEAV
>> IF (KHEAVY(ip) .EQ. 6) THEN
>> WRITE (82,*) JTRACK, ETRACK-AM(JTRACK), XSCO, YSCO, ZSCO,
>> & TKHEAV(ip), CXHEAV(ip), CYHEAV(ip), CZHEAV(ip), WHEAVY(ip)
>> ENDIF
>> 30 continue
>> RETURN
>>
>> But I am not sure to do the difference between alphas like that. What is
>> the
>> difference between alphas in GENTSK and in FHEAVY?
>>
>> Thanks for your help
>>
>> Julien
>>
>> CELIA FRANCE
>>
>>
Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
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(image/jpeg attachment: alphaprompt.jpg)
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