Re: [fluka-discuss]: Energy Deposition is zero

From: Jyoti <jyoti.grg_at_britatom.gov.in>
Date: Thu, 5 Mar 2020 11:35:31 +0530 (IST)

Dear Paola,
While covering the pool with user bins, I kept the detectors at certain distances. Since I can't have a point detector in FLUKA, I filled the detectors with water.
Still, I am getting zero energy depositions at detectors kept at 1m away from the source. I need a sufficient number of values to derive any curve.
Please guide.

Also, I came to know about the weight window method of biasing. How to define weight window for my geometry? A contsnat weight window is not helping.

With Regards,
Jyoti

----- Original Message -----
From: "Paola Sala" <paola.sala_at_mi.infn.it>
To: "Jyoti" <jyoti.grg_at_britatom.gov.in>
Cc: "fluka-discuss" <fluka-discuss_at_fluka.org>, "owner-fluka-discuss" <owner-fluka-discuss_at_mi.infn.it>
Sent: Sunday, February 9, 2020 3:12:26 PM
Subject: Re: [fluka-discuss]: Energy Deposition is zero

Dear Jyoti,
if I understand correctly your input file, you are trying to detect
photons after a path of 5 metres in water, and original energy of the
photons is 1.15 MeV.
At 1 MeV, the mean free path for photons in water is around 14 cm. It
means that the photons have to travel 35 mean free paths before arriving
to your detector, corresponding to an attenuation factor of about 10^-15.
..your bias would need to be much more aggressive than the factor 1000 in
your input, beyond the allowed factors for the BIASING card, that can
span up to a factor 10^10, and beyond a safe use of biasing.
My suggestion would be to cover your pool with userbins, scoring energy
and particle fluence, from which you can derive attenuation curves
Hope this helps
Paola


>
> Dear FLUKA Experts,
> I have taken a point source at (0,0,0).It is shielded by a rectangular
> pool of water around it.
> I am calculating energy deposition at the surface of the pool, but it is
> coming zero.
> I tried importance sampling, yet the answer is zero.
>
> I have attached my input file. Kindly have a look at it.
> Please let me know, where I am doing a mistake.
>
> Thank You
>
> With Regards,
> Jyoti
>
>
>
>


Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148


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Received on Thu Mar 05 2020 - 08:59:00 CET

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