Dear Milena,
you can find the answer to your question in this note to the list of
particles which can be transported with FLUKA:
(1) Heavy fragments produced in evaporation are loaded in a special stack
(COMMON FHEAVY, contained in the INCLUDE file with the same name).
The internal code for heavy evaporation fragments is the following:
3 = deuteron, 4 = 3-H, 5 = 3-He, 6 = 4-He, 7-12 = fission fragments.
Transport capabilities (dE/dx, with account of effective charge and
effective charge straggling, multiple Coulomb scattering, no interaction
yet) are now available for d, t, 3-He and 4-He. Heavier ions can be
transported on demand (see option IONTRANS), with or without nuclear
interactions. Fission fragments and fragments from Fermi break-up, when
produced, are also put in COMMON FHEAVY with id's ranging from 7 to 12
(usually 7 and 8 for two fragments).
and further information is provided in the description of commands IONTRANS,
PHYSICS (with SDUM=EVAPORATion) and RESNUCLEi (Note 4).
Alberto
On Fri, 6 Dec 2013, Milena Quittnat wrote:
> Dear Alberto and FLUKA experts,
>
> thank you very much for your reply, I understood this part now.
> As I learned to better ask one question at a time, I would like to know now what "heavy fragment transport activated" for the "precision default" means in detail?
> Is it in any way related to the "heavy ion transport" of the card IONTRANS?
> Thank you very much for your help
> Milena
>
>
>
> On Dec 4, 2013, at 2:31 PM, Alberto Fasso' <fasso_at_slac.stanford.edu> wrote:
>
>> Dear Milena,
>>
>> indeed your previous mail was containing so many questions, that nobody
>> dared to try answering them...
>> But now that there is just one question, and clearly written, let's
>> answer it.
>> In real life, photons do not deposit (directly) ANY energy, because they
>> do not have a charge. All energy is deposited by electrons and positrons
>> which the photons have generated or set in motion, by photoelectric effect,
>> Auger effect, Compton scattering or pair production.
>> In FLUKA, however, photons have a transport energy cutoff: when their
>> energy becomes equal or lower than the cutoff, the photons are stopped and
>> their energy is deposited there. This small part of the total energy
>> deposition is what you score as "photon energy deposition". It is important
>> to realize that it is an artifact due to the transport thereshold: all
>> energy is deposited by electrons.
>> Try to increase the photon transport threshold by means of command EMFCUT:
>> you will see that the photon energy deposition increases and the electron
>> one decreases.
>>
>>
>>
>> On Wed, 4 Dec 2013, Milena Quittnat wrote:
>>
>>> Dear FLUKA discuss,
>>> as I did not get any answer until now, I would like to shorten up my
>>> questions, in case they were just too simple or too many:
>>> When I am scoring the deposited energy of electrons or positrons, I am
>>> getting rather high results.
>>> I attached the corresponding plot to this mail.
>>> I understood that this is the deposited energy of my whole particle flux of
>>> 8E9 protons/s as I am assigning a cooling time, e.g.:
>>> * score dep Energy for electrons
>>> USRBIN 10. ENERGY -71. 1.25 1.25
>>> 15.depEeI
>>> USRBIN -1.25 -1.25 0. 1. 1. 15.
>>> &
>>> DCYSCORE 2. depEeI
>>> USRBIN
>>> AUXSCORE USRBIN ELECTRON depEeI
>>> My question would be why the energy deposition for electrons and positrons
>>> is that high compared to photons.
>>> Does the energy deposition also include the mass of the electrons?
>>> Thank you very much for your help
>>> Milena Quittnat
>>> On Nov 25, 2013, at 6:08 PM, Milena Quittnat
>>> <milena.eleonore.quittnat_at_cern.ch> wrote:
>>>
>>> Dear FLUKA discuss,
>>>
>>> as the answer to a previous problem was incredibly helpful, I am
>>> hoping for some more help with the following issue:
>>>
>>> I try to score the energy emitted by unstable isotopes in an YSO
>>> crystal during irradiation.
>>> As Yttrium has a large cross section for thermal neutron capture
>>> (1.3 barn), it might produce a prohibitive background to the
>>> general light output, a "constant noise".
>>> My goal is to score the de-excitation- and decay-products of the
>>> created isotopes, mainly the emitted photons and the (overall)
>>> deposited energy.
>>> With this information I would like to study if the isotopes,
>>> e.g. the emitted gamma rays, induce further scintillation.
>>>
>>> I attached my input file, please don't mind the other crystals
>>> placed behind the 15 cm YSO crystal, they are part of the
>>> experimental irradiation setup.
>>>
>>> My questions would be:
>>> - Do I set the right values for the RADDECAY card? Shall I
>>> enable some biasing features in order to increase the statistics
>>> for the decay products?
>>> - Does "prompt radiation" in the RADDECAY card solely refer to
>>> the EM-shower or does it also include photons emitted by the
>>> unstable isotopes? I currently suppress it as I am just
>>> interested in the decay radiation.
>>>
>>> - I do not fully understand the precision default: in the
>>> manual, it says "heavy fragment transport activated". Are
>>> protons and light isotopes scored at the end of their path?
>>> Does it correspond to the "heavy ion transport" with the card
>>> IONTRANS?
>>>
>>> - As I said, I would like to know the deposited energy from the
>>> created isotopes. Both, the overall deposited energy and the EM
>>> energy (BIN 70/71), associated with a cooling time, give rather
>>> high results (ca. 4e6 GeV/cm^3/p).
>>> Where is my mistake?
>>> - I also tried to score the deposited energy created by the
>>> Yttrium isotopes (unit 81) only, but I guess the information is
>>> not directly accessible?
>>> When I am scoring the residual nuclei, I have a high amount of
>>> Yttrium isotopes, e.g. Y86 which changes to Sr86 electron
>>> capture and ?+decay.
>>> Above all, I am not necessarily interested from which isotope
>>> the emitted photons or the deposited energy come from, but
>>> from the total amount produced.
>>>
>>> - If I score the photons with USRTRACK without a cooling time
>>> associated, do I just score the "prompt" photons of the EM
>>> shower and no "secondary" produced ones? That would explain why
>>> my "UTrkPh" (BIN 92) is empty.
>>>
>>> - Did I understood correctly that the EMF cut accounts also for
>>> decay particles? Would you recommend a special biasing with
>>> "EMF-Bias" for my problem?
>>>
>>> I would also like to understand how the photon emission,
>>> metastable isotopes and de-exciation processes are handled in
>>> FLUKA.
>>> For instance how is the photon emission in a Co60 decay
>>> described in FLUKA?
>>> Are photons, emitted by an isomeric transmission, included when
>>> I score the photon fluence or not?
>>> In a FLUKA discuss thread I read that the excited state of an
>>> isotope itself is not scored, but what is about the emitted
>>> energy?
>>> It would be wonderful if you could give me a short explanation
>>> or guide me to a paper.
>>>
>>> Thank you very much for your help, I am looking forward to the
>>> replies!
>>> Sincerely yours,
>>> Milena Quittnat
>>> <131125_YSO_isotopes_FLUKA_discuss.inp>
>>>
>>
>> --
>> Alberto Fasso`
>> SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025
>> Phone: (1 650) 926 4762 Fax: (1 650) 926 3569
>> fasso_at_slac.stanford.edu
>
>
--
Alberto Fass
Received on Fri Dec 06 2013 - 17:16:02 CET