Re: [fluka-discuss]: How to determine the fraction of deposited energy going into ith scintillation photon emission in the "OPT-PROD" card?
Dear Joe,
you say that having to input the experimental observed N_ph/MeV may not
be correct. But somehow the code needs to know what is the light yield.
If there are reliable theoretical calculations for the material
concerned, the fluka user can perfectly input theoretical values instead
of experimental ones. On the other hands, as Anna said, we have to
understand if photon yields available in the literature are corrected
for all the effect you mention, that are strictly detector dependent. We
have no universal recipe for light production, if you are aware of some
possible general prescription it would be very interesting!
For what concerns Birks, again it depends on how the light yield was
measured. If the yield was measured for minimum ionising particles, than
it does not include (or includes as a small contribution) the
recombination. Again, it is up to the user to understand these data, and
above all it his its responsibility to understand his own detector.
Ciao
Paola
On 11/04/2013 09:44 PM, Anna Ferrari wrote:
> Dear Joe,
>
> I completely agree that this is a slippery terrain. But it is also
> clear that when we (we users) input an experimental value (N_ph/MeV in
> this case) we have to know how this value has been measured and the
> effects included in the measurement, in order to avoid possible
> double-counting. Then I'm afraid that the balance of most of the
> issues you mention is responsability of the user.
> Maybe the authors of this part of the code can add their comments...
>
> Concerning the Birks corrections: since the effect of the quenching is
> one of the ingredients that determine the fraction of deposited energy
> going in light,
> and since on the other hand we give in input the experimental value of
> this fraction (no matter how it's calculated), I think that these
> corrections have not to be considered here (they are at the contrary
> essential when we use directly the information of the deposited energy).
>
> As I said, maybe somebody wants to comment more.
>
> Kind regards,
> Anna
>
> Am Mon, 04 Nov 2013 10:54:30 -0700 schrieb Joseph Comfort
> <Joseph.Comfort_at_asu.edu>:
>> Dear Anna,
>>
>> The input for optical photons is overall confusing, and often some
>> information about the properties of materials is unknown or not
>> available. The fraction of the deposited energy one of the most
>> confusing parameters.
>>
>> It seems to me that using the experimental observed N_ph/MeV may not
>> be correct. This number would include the effects of absorption in
>> the materials, incomplete collection of the light, loss through
>> cookies, etc. At least some of these would be included in the Fluka
>> calculations, leading to possible double-counting the effects. There
>> is also an issue with mixed scintillation/Cherenkov radiation.
>>
>> How are all of these issues, as well as things such as Birk's
>> corrections, balanced with each other?
>>
>> Thank you,
>> Joe Comfort
>>
>> On 11/03/2013 06:37 AM, Anna Ferrari wrote:
>>> Dear Xiaokun Zhao,
>>>
>>> I think you can find already the answer in my previous email, in any
>>> case I repeat here explicitly.
>>>
>>> When you chose OPT-PROD card with sdum=SCINT-WV this means that in
>>> what(1) you have to provide the wavelength of the (first) scintillating
>>> photons emitted. In the example that you cite this is 1.280E-05 cm.
>>> From
>>> this you can calculate the energy of the scintillating photons:
>>>
>>> E=hc/lambda=9.686 eV
>>>
>>> If the experimental data tells yo that the light yield is N_ph photons
>>> per MeV of deposited energy (with N_ph/MeV = 2 x 10^4 in the example),
>>> then the fraction of deposited energy that must go in scintillating
>>> photons is:
>>>
>>> 9.686 eV x N_ph/10^6 eV = 2 x 9.686 10^-2
>>>
>>> Except the factor 2, this is the value you find in the example
>>> (now I don't know where this factor 2 comes from -maybe because only
>>> half energy is supposed to produce the first scintillating line?- but I
>>> don't think this is really relevant for you: the important thing is the
>>> procedure. Somebody can correct me if I'm wrong!).
>>>
>>> Hope it helps,
>>> kind regards
>>> Anna
>>>
>>>
>>>
>>>
>>> Am Fri, 1 Nov 2013 20:28:42 +0800 (CST) schrieb 赵晓坤
>>> <zhaoxk_at_mail.ustc.edu.cn>:
>>>>
>>>>
>>>> Dear FLUKA experts,
>>>> Hello!
>>>> Now,I want to use the "OPT-PROD" card to set some optical
>>>> properties of specified materials. When the SDUM is set to "SCINT-WV"
>>>> ,we can set the "fraction of deposited energy going into ith
>>>> scintillation photon emission". I see an example in the chapter12,it
>>>> gives us the light yield(20000 photons/MeV),but set the "fraction of
>>>> deposited energy going into ith scintillation photon emission" to
>>>> 9.686E-02. Why?
>>>> What I want to know is if know the the light yield(like 20000
>>>> photons/MeV), how can I determine the "fraction of deposited energy
>>>> going into ith scintillation photon emission"?
>>>> Best regards!
>>>> Xiaokun Zhao
>>>>
>>>>
>>>
>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> Dr. Anna Ferrari
>>> Institute of Radiation Physics
>>> Helmholtz-Zentrum Dresden-Rossendorf e.V.
>>> Bautzner Landstraße 400
>>> D - 01328 Dresden (Germany)
>>> Tel. +49 351 260 2872
>>>
>>>
>>
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Dr. Anna Ferrari
> Institute of Radiation Physics
> Helmholtz-Zentrum Dresden-Rossendorf e.V.
> Bautzner Landstraße 400
> D - 01328 Dresden (Germany)
> Tel. +49 351 260 2872
>
Received on Tue Nov 05 2013 - 11:38:38 CET
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