I guess you forgot to adapt the USRBDX energy interval as you increased
the photon energy, this way cutting higher energy photons. In fact, when
scoring up to the max photon energy, I get fully consistent results
(despite the soil effect)
Best
Francesco
**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. +41 22 7678962
fax +41 22 7668854
On Fri, 29 Jun 2018, riya dey wrote:
> Dear Expert,
>
> I changed the cloud media from air to vacuum. Still the total fluence is
> different for different energy. Actually, with increasing energy the total
> fluence in the detector is decreasing which is not expected if the photons
> are propagating in vacuum.
>
> For example, when energy = 0.1 MeV , total cumulative fluence (two way
> scoring) = 3.33E-7 # per cmq per primary , while when energy = 1 MeV, total
> fluence (two way scoring) = 5.03 E-8 # per cmq per primary.
>
> Even with 1E+8 histories, although the statistical error is very less, still
> the two values are different. The sample file is attached here.
>
> -----Original Message-----
> From: owner-fluka-discuss_at_mi.infn.it [mailto:owner-fluka-discuss_at_mi.infn.it]
> On Behalf Of Francesco Cerutti
> Sent: 28 June 2018 23:12
> To: riya dey <riyadey_at_barc.gov.in>
> Cc: FLUKA discussion <fluka-discuss_at_fluka.org>
> Subject: Re: [fluka-discuss]: TOTAL FLUENCE
>
>
> Dear Riya,
>
> I'd share your expectation if your photons were travelling in vacuum, but
> their interactions with your air hemisphere depend on their energy.
>
> Also, make sure that the statistical error of your fluence values is
> reasonably low.
>
> As a side note, in your source routine, when typing any real number put it
> in double precision (e.g., 1.0D0/3.0D0, or - in this specific case - the
> available FLUKA parameter ONETHI).
>
> Kind regards
> Francesco
>
> **************************************************
> Francesco Cerutti
> CERN-EN/STI
> CH-1211 Geneva 23
> Switzerland
> tel. +41 22 7678962
> fax +41 22 7668854
>
> On Wed, 27 Jun 2018, riya dey wrote:
>
>>
>> Dear FLUKA Experts,
>>
>>
>>
>> I was modelling a hemispherical cloud source ( radius = 10 m)
>> emitting photons isotropically. Below the cloud, a detector is placed
>> at ( 0,0,200
>> cm) with radius R= 200 cm. Now, using USRBDX surface crossing fluence
>> rate is estimated in the detector. If we change the energy emitting
>> from the source , lets say for 0.1 MeV , 0.5 MeV , 1 MeV , then
>> although the fluence distribution with energy is different , the total
>> no of particles crossing the detector surface should be nearly same.
>> But total fluence from FLUKA results are different for different energy.
>>
>>
>>
>> What might be the reason for this ?
>>
>>
>>
>> The input files for 0.1 MeV is attached here. The outputs (sum.lis)
>> for 0.1 MeV and 0.5 MeV are :
>>
>>
>>
>> Total fluence per cmq per primary for 0.1 MeV is = 3.59 E-7
>> (one-way
>> scoring) , for 0.5 MeV is = 4.73 E-8 (one way scoring)
>>
>>
>>
>>
>>
>> With regards,
>>
>> Riya Dey
>>
>>
>>
>
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Received on Fri Jun 29 2018 - 19:28:24 CEST