Hi Tamer,
You increase the number of primaries to reduce the statistical uncertainty of the 'observable' that you are trying to measure, not the observable itself.
For example, if you run 5 cycles with N particles and the volumetric energy deposition is E [GeV/cm^3/primary] with er=10% statistical error, you will have to another 15 cycles so that the statistical error is down to about half, i.e. 5%, but the expected energy deposition will still be E (+/- 0.5*er*E).
So going to your question, Fluka will (generally) give you magnitudes per primary (actually per normalized primary statistical weight...), so you need to normalize results to your actual intensity.
For example, if you have an electron beam of power P[kW], with electrons of energy Ee[GeV/e-], with a result from Fluka of E [GeV/(cm^3 e-)], then this means that the fraction of energy deposition per each electron in the beam is E*V/Ee, with V the volume of the scoring.
Thus, the power [kW] deposited in the volume for your beam conditions will be:
P*V*E/Ee
And the energy deposited in a given time interval dT:
P*V*E*dT/Ee
-M
________________________________
From: owner-fluka-discuss_at_mi.infn.it <owner-fluka-discuss_at_mi.infn.it> on behalf of Tamer Tolba <t.tolba_at_fz-juelich.de>
Sent: Sunday, March 22, 2020 7:22 AM
To: paola.sala_at_mi.infn.it <paola.sala_at_mi.infn.it>
Cc: fluka-discuss <fluka-discuss_at_fluka.org>
Subject: Re: [fluka-discuss]: E deposition dependence on incident intensity
Dear Paola,
Thanks so much for your fast reply.
Then, what should I do to export/get the total energy deposited in a volume?
Regards,
Tamer
On 3/22/2020 2:22 PM, Paola Sala wrote:
> Dear Tamer,
>
> Almost all FLUKA estimators (usrbin, usrbdx etc) give results
> normalized per primary particle.
> Thus, they do NOT depend on the number of cycles, nor on the number of
> primaries in the START card.
> Regards
> Paola
>
>> Dear fluka experts,
>>
>> In my "usual" fluka simplified model, usbrea.inp, I am scoring the
>> energy in a specified region, which was hit by a proton beam. Then I am
>> using usbrea code to export the integrated energy deposited in this
>> region for different beam intensities.
>>
>> The problem: I realized that, for a fixed beam energy, increasing the
>> number of runs, hence the number of primaries/beam intensity, does NOT
>> change the value of the integrated energy deposited in the target volume?!
>>
>> Attached, you will find:
>>
>> - usbrea_3Runs_98.bnn file: integrated binary file using flair, for 3
>> Runs (each of 1000 primaries, i.e. 3000 pot).
>>
>> - usbrea_10Runs_98.bnn file: integrated binary file using flair, for 10
>> Runs (each of 1000 primaries, i.e. 10000 pot).
>>
>> - Edep_3Runs.txt file: formatted file for the integrated deposited
>> energy in the specified region, generated by applying usbrea code on
>> usbrea_3Runs_98.bnn.
>>
>> - Edep_10Runs.txt file: formatted file for the integrated deposited
>> energy in the specified region, generated by applying usbrea code on
>> usbrea_10Runs_98.bnn.
>>
>> As you can see, whether integrate over 3 runs or 10 runs, the total
>> deposited energy, in the two txt file, is same in the target volume! Is
>> the integrated deposited energy in a volume is independent of the
>> intensity of the incident radiation? Or I misunderstand some physics?
>>
>> Regards,
>>
>> Tamer
>>
>> --
>> Dr. Tamer Tolba
>> Forschungszentrum Jülich
>> Institut für Kernphysik (IKP)
>> 52425 Jülich, Germany
>> Tel.: +49 2461 61 6860
>> Fax.: +49 2461 61 96415
>>
>>
>>
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>
> Paola Sala
> INFN Milano
> tel. Milano +39-0250317374
> tel. CERN +41-227679148
>
--
Dr. Tamer Tolba
Forschungszentrum Jülich
Institut für Kernphysik (IKP)
52425 Jülich, Germany
Tel.: +49 2461 61 6860
Fax.: +49 2461 61 96415
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Received on Mon Mar 23 2020 - 02:20:37 CET