Hi- this is Lew’s daughter. My father passed away yesterday. Our family loved that he was still collaborating on projects.
Laura Towle
Lktowle_at_comcast.net
408-476-0540
Sent from my iPhone
> On Mar 5, 2020, at 08:19, Paola Sala <paola.sala_at_mi.infn.it> wrote:
>
> Dear Jyoti,
> do not put any detector. Simply, cover your water region with URSBIN.
> Maybe one for energy deposition, another for photon fluence. Choose
> R-phi-z usrbin type, with Z from 0 to 500cm in 100 bins, and Radius..say
> from 0 to 20 cm in
> 20 bins.
>
> These you can plot as 2D plots, and already have an idea of the decrease
> of dose and fluence (and see if the bin limits and size are reasonable).
> Then you can plot a 1-D projection (from the USRBIn plotting page of
> Flair), either averaging over all R or chossing themost central interval.
> This will give you the attenuation of the dose and fluence versus z.
> Weight windows will not help in your case. They are mostly helpful when
> using leading particle biasing, which is not helpful here, either.
>
> Keep in mind, again, that at 1 MeV, the mean free path for photons in
> water is around 14 cm. You will never get anything after 5metres.
>
> After 1 metre, the beam will already be attenuated by 3 orders of
> magnitude (approx)
>
> If you use importance biasing (card BIASING), the thickness of your layers
> should be similar to the mean free path. You cannot do up to 5 metres,
> though.
>
> Hope this helps
> Paola
>
>> 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
>>
>>
>> __________________________________________________________________________
>> You can manage unsubscription from this mailing list at
>> https://www.fluka.org/fluka.php?id=acc_info
>>
>
>
> Paola Sala
> INFN Milano
> tel. Milano +39-0250317374
> tel. CERN +41-227679148
>
> __________________________________________________________________________
> You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?id=acc_info
>
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Received on Thu Mar 05 2020 - 23:56:35 CET