Re: [fluka-discuss]: UsrMed Energy modulation

From: Paola Sala <paola.sala_at_mi.infn.it>
Date: Mon, 25 Aug 2014 10:29:36 +0200

Dear Yuri
1) the command is BDY2NM, but the input is the name of the body, not the
name of the material. The name of the body as you defined it in your
geometry. Be careful to give it left-justified in the 8 charachter
variable.


2) no, a body of zero thickness will nort work. What about shrinking or
translating the body out of the beam ? ( always chack that the geometry
still works..).

Regarda
Paola

> Dear Paola,
>
> I will try this in the next couple of days.
> 1. Is there a chance that the right command is not "NM2BDY ", but
> "BDY2NM"? I tried "BDY2NM" but for different materials I always get
> the number "538976288"
> 2. Our Mesh foil has also holes in it, which means zero shift. I
> suppose it is not right to use SETBDY to set the thickness of the body
> to zero?
>
> Regards
> Yuri
>
> 2014-08-21 10:56 GMT+02:00 Paola Sala <paola.sala_at_mi.infn.it>:
>> Dear Yuri,
>> perfect, we can start already with a source.f, that you can later modify
>> for your further needs.
>> The standard version of the source.f takes the parameters given in the
>> BEAM and BEAMPOS cards to defin a monochromatic pencil beam, therefore
>> for
>> the moment you do not need to modify this part.
>>
>> Fluka works internally with numbered lists of bodies and regions, so
>> the
>> first job is to convert the name of the body that you need to
>> move/change
>> into the internal fluka number.
>> In the source.f, "first call initialisation" part, retrieve and save the
>> number of the body that you need to move:
>>
>> CALL NM2BDY ( BODNAM, IBODY, IERR )
>> BODNAM is a charachter*8 variable containing the body name, left
>> justified
>> IBODY returns the body number
>> IERR is an error code, =0 means OK, =1 means body not found
>>
>> It is a good practice to add a " SAVE IBODY" declaration in the routine
>> header
>>
>>
>> Then, event by event you chan change the parameters defining your body,
>> taking care not to introduce geometry errors, via a call to
>>
>> SUBROUTINE SETBDY ( IBODY, ITYPE, BDYFIN, NBDYFI )
>>
>> Where
>> input:
>> IBODY is the output of nm2bdy
>> ITYPE is the type of body. I attach a list of correspondence, for
>> instance
>> an XYP is input number 12
>> BDYFIN is a vector containing the body papameters in the same order as
>> in
>> the fluka input cards. These values will override the ones given in the
>> input cards.
>> NBDYFI is the number of parameters (see attached list)
>>
>>
>> For instance, you can define the foil with an RPP and change runtime the
>> position of the exit face, Or define the foil faces with two planes and
>> change the position of one of them.
>>
>> In this way, you can modulate the thickness of the foil according to
>> your
>> range shift probability.
>>
>> Moreover, if you will later on modify the source in order to define a
>> geometrically spread beam, you can even choose the thickness correlated
>> with the primary C12 position.
>>
>> Hope this helps
>> Paola
>>
>>
>>> Dear Paola,
>>> Right now I am using the normal Beam Card with C12, momentum
>>> spread=0,angular distr. = 0, but I am planning to use the source.f
>> routine in the near future.
>>> Regards
>>> Yuri
>>> 2014-08-20 10:39 GMT+02:00 Paola Sala <paola.sala_at_mi.infn.it>:
>>>> Dear Yuri,
>>>> sorry, but I have to confirm that changing the energy in usrmed is NOT
>> possible. It may seem to work, but it doesn't, it spoils preset
>> quantities.
>>>> There is a better and safer way to perform what you plan, that is to
>> change the thickness of your foil event by event. In this way all the
>> simulation will be self-consistent. I'll explain you how to do, only I
>> would like to know if you are already using a "source.f" routine or
>> not.
>>>> Regards
>>>> Paola
>>>>> Dear Paola,
>>>>> thank you for your answer!
>>>>> We have the following idea: There is a thin foil in the nozzle of a
>> particle therapie device. This foil has mesh structure and therefore:
>> 1. shifts the Bragg Peak of C12 Ions
>>>>> 2. modulates(broadens) the BP
>>>>> We want to take these 2 effects into account in Fluka. As it is quite
>> difficult to modell the mesh foil geometrically, we decided to replace
>> the mesh foil with a homogeneous one. This will only shift the BP. In
>> order to broaden it we want to use the UsrMed routine. The modulation
>> function of the foil (probability vs. particle range shift) is already
>> known. We want to sample from this function delta_z ("particle shift"
>> in cm) and convert it to delta_E using an ICRU49 equation. Delta_E
>> will be then added to the original Energy of the particle. This way we
>> can artificially broaden the BP.
>>>>> Actually we already tried this and it seems to work fine. The only
>> problem is that I still use in my equation Z and A from the projectile
>> (IPROZ, IPROA), whereas I need the specific Z and A of each particle
>> flying into the material. Do you know how I can access them?
>>>>> Best regards
>>>>> Yuri
>>>>> 2014-08-17 17:32 GMT+02:00 Paola Sala <paola.sala_at_mi.infn.it>:
>>>>>> Dear Yuri Simeonov,
>>>>>> The energy of particles cannot be changed inside usrmed.f,
>> attempting
>>>>>> to
>>>>>> do s it would make the program crash or give meaningless results. If
>>>>>> you
>>>>>> could explain in more detail your problem could try to see if there
>>>>>> is
>>>>>> a
>>>>>> way to solve it.
>>>>>> Regards
>>>>>> Paola
>>>>>>> Dear fluka experts,
>>>>>>> I want to use UsrMed.f routine to modulate the energy of each
>>>>>>> particle,
>>>>>>> which is transported into a user-defined material (Initial source
>>>>>>> is
>> C12).
>>>>>>> As I calculate the energy using an equation, I need to know the
>> specific Z
>>>>>>> and A of each particle inside the UsrMed (Z will vary due to
>> fragmentation). Which variables should I use?
>>>>>> Paola Sala
>>>>>> INFN Milano
>>>>>> tel. Milano +39-0250317374
>>>>>> tel. CERN +41-227679148
>>>> Paola Sala
>>>> INFN Milano
>>>> tel. Milano +39-0250317374
>>>> tel. CERN +41-227679148
>>
>>
>> Paola Sala
>> INFN Milano
>> tel. Milano +39-0250317374
>> tel. CERN +41-227679148
>>
>>
>


Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
Received on Mon Aug 25 2014 - 11:40:34 CEST