Re: [fluka-discuss]: Regarding importance biasing

From: George Kharashvili <georgek_at_jlab.org>
Date: Wed, 20 Jun 2018 13:42:37 -0400 (EDT)

Hello Sujoy,

Importance biasing can be set from 0.0001 to 100000. So the importance of all regions can be set to 0.0001 by the first BIASING card and then increase by a factor of 2 for every next layer, up to 100000. These are hard limits and, as far as I know, there is nothing you can do to change them.
WHAT(1)=3 will only apply to neutrons with energy less than 20 MeV, but you can use WHAT(1)=0.0 (all particles) or WHAT(1)=1.0 (hadrons, heavy ions, and muons), both of which will apply importance biasing to all neutrons and will most likely give the same, or very similar results for a typical neutron shielding problem.

Cheers,
George

----- Original Message -----
From: "Sujoy Chatterjee" <sujoy_at_vecc.gov.in>
To: "FLUKA Discussion List" <fluka-discuss_at_fluka.org>
Sent: Wednesday, June 20, 2018 4:02:08 PM
Subject: [fluka-discuss]: Regarding importance biasing

Hello FLUKA experts,

The importance biasing of a region can be set up to 10^5 as seen from the FLUKA courses lectures. Now for my problem of shielding neutrons, it has been observed that the DOSE-EQ due to neutrons becomes 1/2 after 10 cm of concrete. So, I started putting Imp=2, 4, 8 .... for every 10 cm of concrete. As I have to study upto a thickness of 600 cm of concrete, I donot know how to tackle this problem as for deeper thicknesses the Imp values are going beyond 10^5.
Another question is regarding the WHAT(1) parameter of the Biasing card. The neutrons which I am studying is a spectrum from thermal to 50 MeV. If I put WHAT(1)=3 for low energy neutrons, do I require separate Biasing card for neutrons beyond 20 MeV ? Can the value of WHAT(1)=1.0 take care of all the neutrons, i.e., below 20 MeV and above 20 MeV ?

Thank you.

with regards,
डॉ. सुजय चटर्जी/Dr. Sujoy Chatterjee
भाभा परमाणु अनुसंधान केंद्र/Bhabha Atomic Research Centre
1/ए एफ विधान नगर/1/AF-Bidhannagar,
कोलकाता - 700064/Kolkata - 700064
Alt. Email: sujoy_at_barc.gov.in

__________________________________________________________________________
You can manage unsubscription from this mailing list at https://urldefense.proofpoint.com/v2/url?u=https-3A__www.fluka.org_fluka.php-3Fid&d=DwIFaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=VEsjWcjHR_RwJLerQJyK4g&m=-0Z2YhNM-ym9LmhTP3CGzobvdldJcrudzNpUQ_DMgbo&s=kmStDiIca-4xlotrU4KB5Du3TWBtAhGjLvmYa75c1g8&e= �c_info

__________________________________________________________________________
You can manage unsubscription from this mailing list at https://www.fluka.org/fluka.php?idc_info
Received on Wed Jun 20 2018 - 21:01:48 CEST

This archive was generated by hypermail 2.3.0 : Wed Jun 20 2018 - 21:02:01 CEST