RE: [fluka-discuss]: TOTAL FLUENCE

From: riya dey <riyadey_at_barc.gov.in>
Date: Fri, 29 Jun 2018 17:12:43 +0530

It is very surprising to note that those two inputs with their corresponding
source file, gives me different result. But according to you, you are
getting same result as expected theoretically. But the same inputs while
running in my pc give different result. How many histories are you using ?
For the clarification I am attaching both the input, their source files and
USRBDX on 22 unit result . Kindly have a look into my results.

Or , is there any installation problem so that I am getting wrong results ?


If possible, kindly attach the output files for both the energy.


-----Original Message-----
From: owner-fluka-discuss_at_mi.infn.it [mailto:owner-fluka-discuss_at_mi.infn.it]
On Behalf Of Francesco Cerutti
Sent: 29 June 2018 16:07
To: riya dey <riyadey_at_barc.gov.in>
Cc: FLUKA discussion <fluka-discuss_at_fluka.org>; riyadey0293_at_gmail.com
Subject: RE: [fluka-discuss]: TOTAL FLUENCE


Riya:

if you run the two inputs you attached with your source.f embedding the
respective TKEFLK value (0.001 GeV and 0.0001 GeV), you get *in both
cases* an integral fluence value on unit 22 of 3.4E-7 per cmq per primary:

Tot. resp. (Part/cmq/pr) 3.4233489E-07 +/- 3.171398 % (1 MeV)

Tot. resp. (Part/cmq/pr) 3.3571294E-07 +/- 0.4070479 % (100 keV)

So the problem is not there.

Still, in the 1 MeV case, you are cutting at scoring level the (limited)
contribution of photons below 100 keV and above your 10 keV transport
threshold (these come from the interaction with the soil).

In order to avoid to hard-code in the source.f the energy value and be
forced to recompile it every time, you can set it in the first WHAT of the
SOURCE card and acquire it by the statement

       TKEFLK (NPFLKA) = WHASOU(1)

Cheers
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,
>
> In reference to the previously attached two input files, if you get
> same result for both the energy kindly share the output file.
>
> -----Original Message-----
> From: riya dey [mailto:riyadey_at_barc.gov.in]
> Sent: 29 June 2018 14:25
> To: 'Francesco Cerutti' <Francesco.Cerutti_at_cern.ch>
> Cc: 'riyadey0293_at_gmail.com' <riyadey0293_at_gmail.com>
> Subject: RE: [fluka-discuss]: TOTAL FLUENCE
>
> Dear expert,
>
> I am sorry to say that I could not get the issue. The two inputs that
> I have used for 0.1 MeV and 1 MeV is attached here.
>
> -----Original Message-----
> From: Francesco Cerutti [mailto:Francesco.Cerutti_at_cern.ch]
> Sent: 29 June 2018 14:15
> To: riya dey <riyadey_at_barc.gov.in>
> Cc: FLUKA discussion <fluka-discuss_at_fluka.org>; riyadey0293_at_gmail.com
> Subject: RE: [fluka-discuss]: TOTAL FLUENCE
>
>
> 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 - 23:24:05 CEST

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