Re: [fluka-discuss]: Scoring alphas in FLUKA using USRBIN

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Sat, 3 Sep 2016 13:12:39 +0200

Hi Shri,

please read the manual, LOW-NEUT card, Note 5.

In particular, you need to have pointwise treatment activated (which is
already the case for PRECISIO defaults) as well as a LiF compound
definition containing explicitly the LITHIU-6 material as elemental
component. The latter has to be in turn defined by a MATERIAL card
specifying monoisotopic composition (see again the manual and avoid the
usual mistake mixing up the mass number in WHAT(6) - which is what you
have to fill, with the number 6.0 - and the atomic weight in WHAT(2) - not
to be filled at all -).

Note in addition that your PART-THR card makes no sense, since 1eV is
patently not an option as transport threshold, being 1keV the hard cutoff
for everything but neutrons and photons.
And, as a general rule, do not limit the full transport to 4-HELIUM only,
as you did with IONTRANS, rather let it be applicable to all heavy
and light ions (put HEAVYION, i.e. particle code -2, as explained in the
manual).

Best

Francesco

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

On Sat, 3 Sep 2016, Srinidhi Bheesette wrote:

> Hi all,
> I wish to score alphas produced by the reaction of thermal neutron( 0.025eV)
> with Lithium Fluoride moderator.
>
> I am using a 0.025eV neutron point source for my simulations and scoring the
> a silicon detector which is bonded to the moderator. 
> I have enabled the transport using the following card
>
> IONTRANS    4-HELIUM
>
>
> and also changed the threshold to 1eV for alphas using the following card: 
>
> PART-THR      -1.E-9  4-HELIUM                           0.0
>
>
> Finally I score the flux on the moderator using the following card:
>
>
> USRBIN           10.  4-HELIUM       22.  0.700067  0.880124    
> -0.10convalp
>
> USRBIN     -0.702433   -0.5261     -0.11      256. 256.        
>
> 1. &
>
>
> and on the silicon detector using the following card:
>
>
> USRBIN           10.  4-HELIUM       29.  0.700067  0.880124   0.10sialph
>
> USRBIN     -0.702433   -0.5261    -0.096      256. 256.        1. &
>
>
> But in vain, as I do not see any alpha particles scored. The fort files are
> filled all with zeros.
>
> Please let me know where I am going wrong. Help would be greatly
> appreciated.
>
> Thanks in advance. 
>
> Cheers,
> Shri
>
> (Srinidhi Bheesette)
>
>

__________________________________________________________________________
You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?id=acc_info
Received on Sat Sep 03 2016 - 14:39:24 CEST

This archive was generated by hypermail 2.3.0 : Sat Sep 03 2016 - 14:39:33 CEST