Re: A neutron problem

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Sun, 29 Nov 2009 21:11:10 +0100

Dear Ali,

if you wish to get 3D maps of neutron fluence in the cavity corresponding
to different neutron energy ranges, you can clone a USRBIN detector in
your input and link a fluscw routine (to be activated by USERWEIG with
WHAT(3)=3.0) where, according to the USRBIN index value (JSCRNG, for
ISCRNG = 2), you prevent from scoring (setting LSCZER=.TRUE.) unless the
neutron energy (PLA, check the sign according to the routine header) falls
in the respective range. Of course the latter will be approximated by the
group structure (your 4 eV limit becomes 3.927864 eV and the 10keV one
10.33298 keV).
[If instead you look at the neutron spectrum averaged over the cavity as
produced by USRTRACK, neutron fluences corresponding to the indicate
ranges are obviously immediately given by the integration of the spectrum
over these energy ranges].

Hope this helps

Francesco

**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. ++41 22 7678962
fax ++41 22 7668854

On Sun, 29 Nov 2009, ali taheri wrote:

> Dear Francesco,
>
> In fact my problem is to determine the neutron flux in these 3
> ranges: 0 to 4 eV , 4eV to 10 keV and 10 keV to 10 MeV .
> Of course I've used the pre-defined bins to plot neutron spectrum,
> but in BNCT (is a kind of neutron therapy) it's needed also that we
> know these fluxes separately!
>
> Thank you for your attention
> Ali
>
> On 11/29/09, Francesco Cerutti <Francesco.Cerutti_at_cern.ch> wrote:
>>
>> Dear Ali,
>>
>> I miss the problem. The 260 pre-defined bins (from 20 MeV down to 1e-5 eV)
>> are indicated in the manual and are printed in the neutron scoring files.
>> The transport of neutrons below 20 MeV cannot prescind from this binning
>>
>> Ciao
>>
>> Francesco
>>
>> **************************************************
>> Francesco Cerutti
>> CERN-EN/STI
>> CH-1211 Geneva 23
>> Switzerland
>> tel. ++41 22 7678962
>> fax ++41 22 7668854
>>
>> On Sun, 29 Nov 2009, ali taheri wrote:
>>
>>> Dear Fluka Users
>>>
>>> Hi
>>> I am working on a simple Neutron source,there is a vacuum cavity
>>> and I need to know the neutron fluence in thermal,epithermal and
>>> fast ranges separately in the cavity.
>>>
>>> As I knew,in Fluka we can't specify energy bins for neutrons! please
>>> help me to solve this problem.
>>>
>>> I'd be thankful to you for help
>>>
>>> Best Regards
>>> Ali Taheri
>>>
>>>
>>
>
Received on Sun Nov 29 2009 - 22:15:22 CET

This archive was generated by hypermail 2.2.0 : Sun Nov 29 2009 - 22:15:22 CET