Re: [fluka-discuss]: EMFIX_STEPSIZE_for_electron_dose_thinslab

From: Sougata <sougata_at_barc.gov.in>
Date: Wed, 25 Sep 2019 17:25:41 +0530

Dear Ilaria,

Thank you veru much for your reply.
I have used the MULSOPT card as you suggested. Please note the
observations on energy deposition for 500 keV mono energetic e- beam in
a thin slab of thickness 0.004 cm (TISSUEIC material)surrounded by same
material. as I mentioned in trailing email.

*Please see attached .imp file for reference.
Observation :

NO EMFFIX STEPSIZE MULSOPT Energy deposited(GeV)
=====================================================================
1 on off off 2.4987E-6
2 on off on 2.5447E-6
3 off off on 2.5475E-6
4 on on off 2.0206E-6
5 off on off 2.0177E-6

All reults have %error is less than 0.5%.

So possibly when we activate STEPSIZE card a variation of ~20% observed.
e So which is correct combination for dose evaluation from e- beam
related to above problem.


Thanks & Regards,
-- 
SOUGATA RAKSHIT / सौगत रक्षित
Scientific Officer(D) / वैज्ञानिक आधिकारीक(D)
RSSD / आर एस एस डि
Bhabha Atomic Research Centre / भाभा परमानु अनुसंधान केंद्र
Mumbai-400 085 / मुंबई-400 085
Tel: +91-022-2559 2214/ दूरभाष: +91-022-2559 2214
On 2019-09-20 23:50, Maria Ilaria Besana wrote:
> Dear Sougata,
> 
> there is not a general receipt to set the EMFIX and STEPSIZE values.
> It depends on your specific problem.
> I have however some general suggestions.
> I would recommend to use as low thresholds as possible for electrons
> and photons.
> In addition to this you can consider to activate single scattering,
> using the MULSOPT card.
> Replacing multiple scattering with single scattering can be very
> demanding in terms of CPU, but it can work for your case, since you
> are interested in a very thin layer and low energy particles.
> Please have a look at the MULSOPT card in the manual, especially at 
> Note 6.
> 
> Hope that helps,
> best regards,
> Ilaria
> 
>> On 18 Sep 2019, at 07:39, Sougata <sougata_at_barc.gov.in> wrote:
>> 
>> Dear Fluka users,
>> 
>> I am trying to evaluate  dose from electron beam  in tissue. Energy of 
>> electron is 100 keV to 2 MeV for different cases.  For this I am 
>> taking thin slab of thickness 0.004 cm (TISSUEIC material) which is 
>> surrounding by similar material. I have set transport/production 
>> cutoff at lowest available. I am scoring energy deposition. Fluka  
>> default is set at PRECESSION. My queries are as following
>> 
>> 1. Is there any requirement to apply EFMIX and/or STEPSIZE for this 
>> case as I am scoring energy deposition in thin slab? If yes how to 
>> optimize. Because I observed variation of ~20% by applying maximum 
>> STEPSIZE of 0.0001 cm for the present input (FILE ATTACHED). Please 
>> elaborate.
>> 
>> 2. What other precaution should I take for dosimetry at low energy 
>> electron for example  around 100 keV ?
>> 
>> --
>> SOUGATA RAKSHIT / सौगत रक्षित
>> Scientific Officer(D) / वैज्ञानिक आधिकारीक(D)
>> RSSD / आर एस एस डि
>> Bhabha Atomic Research Centre / भाभा परमानु अनुसंधान केंद्र
>> Mumbai-400 085 / मुंबई-400 085
>> Tel: +91-022-2559 2214/ दूरभाष: +91-022-2559 
>> 2214<betaVOL-500keV-TSUEIC-p004cm_aa.inp>
> 
> 
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Received on Wed Sep 25 2019 - 15:18:00 CEST

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