# Re: [fluka-discuss]: RE: EXPRESSIONN OF AREA USED IN USRBDX CARD

From: Francesc Salvat-Pujol <francesc.salvat.pujol_at_cern.ch>
Date: Mon, 12 Mar 2018 10:59:03 +0100

Dear Witness,

Feel free to take a look at the scoring lecture

https://indico.cern.ch/event/604018/contributions/2435691/attachments/1395454/2242757/08_Scoring_2017.pdf

You can see previous course contents e.g. under

https://indico.cern.ch/event/604018/timetable/#all

Click on the paper clips in each block to see the corresponding PDFs.

With kind regards,

Cesc

On Fri, Mar 09 2018, at 13:18 +0200, Witness Chirume wrote:
>
>hello,
>
>i hope i find you well, i am a fluka beginner, i found your lecture notes
>on the link that you provided to be useful. may you please send me some
>more basic tutorials for beginners. especially on scoring.
>
>Regards
>Witness Chirume
>
>On 5 March 2018 at 13:08, Francesc Salvat-Pujol <
>francesc.salvat.pujol_at_cern.ch> wrote:
>
>> Dear Riya,
>>
>> I have not seen your input file, so I shall assume you have a beam of
>> whichever particles impinging on a sphere in vacuum with no additional
>> regions other than a surrounding blackhole and that you are indeed
>> scoring fluence. I naively suspect your problem is the following.
>>
>> If you score fluence using USRBDX with one-way scoring vacuum->sphere,
>> you are only scoring surface-crossing events on the first half of the
>> spherical surface, as the other half corresponds to sphere->vacuum.
>> Thus, you are a factor ~2 short if you want the fluence through the
>> whole spherical surface.
>>
>> If you use USRTRACK, the fluence scoring is done by accumulating track
>> lengths within the sphere (and dividing by the sphere volume in the end
>> etc). Thus, here you pick up the whole passage through the sphere, not
>> just the entrance as above, hence (probably) the observed discrepancy.
>>
>> Feel free to take a look e.g. at
>> https://indico.cern.ch/event/604018/contributions/2435691/at
>> tachments/1395454/2242757/08_Scoring_2017.pdf
>>
>> Cheers,
>>
>> Cesc
>>
>>
>>
>> On Mon, Mar 05 2018, at 14:22 +0530, riya dey wrote:
>>
>>>
>>> Dear Experts,
>>>
>>> If I put 4*pi*r^2 as area in USRBDX ( with one way scoring) and
>>> 4/3*pi*r^3
>>> as volume of the spherical detector in USRTRACK , then the result in
>>> USRTRACK is appearing to be 2 times the value from USRBDX.
>>>
>>> Both the values should be the same theoretically. Why is this discrepancy
>>> happening ?
>>>
>>>
>>>
>>> With regards,
>>>
>>> Riya Dey
>>>
>>>
>>>
>>> Sent: 05 March 2018 13:47
>>> To: 'fluka-discuss_at_fluka.org' <fluka-discuss_at_fluka.org>
>>> Subject: EXPRESSIONN OF AREA USED IN USRBDX CARD
>>>
>>>
>>>
>>> Dear FLUKA Experts,
>>>
>>>
>>>
>>> Suppose I want to calculate the fluence from vacuum to a spherical
>>> target .
>>> What should be the expression for area that has to be given in USRBDX
>>> card
>>> ?? Is it 4*pi*r^2 or pi*r^2 ??
>>>
>>>
>>>
>>> Note : Fluence is defined as dN/dA where dN the number of particles
>>> incident
>>> on a sphere of cross-sectional area dA. And the cross sectional area of a
>>> sphere is pi*r^2 .
>>>
>>>
>>>
>>> With regards,
>>>
>>> Riya Dey
>>>
>>>
>> --
>> Francesc Salvat Pujol
>> CERN-EN/STI
>> CH-1211 Geneva 23
>> Switzerland
>> Tel: +41 22 76 64011
>> Fax: +41 22 76 69474
>>
>> __________________________________________________________________________
>> You can manage unsubscription from this mailing list at
>> https://www.fluka.org/fluka.php?id=acc_info
>>
>>

```--
Francesc Salvat Pujol
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
Tel: +41 22 76 64011
Fax: +41 22 76 69474
__________________________________________________________________________
You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?id=acc_info
```
Received on Mon Mar 12 2018 - 12:16:46 CET

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