Re: Fluka simulation and its experimental verification

From: Alberto Fasso' <>
Date: Thu, 20 Jun 2013 10:14:57 +0200

Dear Dr. Patil,

I think that the simplest way to check the neutron spectra calculated by FLUKA
is the activation technique using several activation detectors with different
thresholds, although it cannot cover the whole energy range you are interested
in. You can fold the neutron spectra calculated by FLUKA by the cross section
of different threshold detectors and verify if the result agrees with your
Try "threshold activation detectors" on Google, and you will find many
lists of useful ones. I suggest that you look for instance at Table 1 of the
article by Kardan et al., Radiation Measurements 38, pp. 185–191 (2004).
As you can see, the lowest energy thresholds are those of the reactions
103-Rh(n,n')103m-Rh (150 keV), and 115-In(n,n')115m-In (600 keV). You cannot
measure neutrons with energy less than 150 keV by the activation technique,
but above this energy there are many possibilities.


On Wed, 19 Jun 2013, Dr. Bhushankumar J. Patil wrote:

> Dear fluka users and developers,
> This mail is in connection with the fluka simulation and its
> experimental verification.
> We have designed Accelerator Based Neutron source using FLUKA
> simulation for our 6 MeV Race-Track Microtron. In this case high
> energy electron is impinged on the Tungsten target to generate
> bremsstrahlung radiation, which further produces neutrons by photo nuclear
> reaction in Beryllium target. The optimization of these
> targets along with their spectra were estimated using fluka code.
> The measurement of neutron flux was carried out by activation of
> vanadium and compared with the integrated flux calculated in
> fluka.
> The developed accelerator based neutron source generates
> continuous neutron spectrum having energy range from 1 keV to 4
> MeV. Therefore, knowledge of the spectral shape of the neutron
> flux is critical
> for interpreting any activation measurement. We have made an attempt to
> quantify the total number of neutrons using a Vanadium activation, but we
> can not verify the spectral shape that is estimated by FLUKA with a direct
> measurement.
> Our neutron flux calculated by fluka is matching very well with the
> measured neutron flux by activation process. These results are also
> published in journal.
> The FLUKA simulations need to be bench marked by spectral
> measurements in order to give confidence in the results. Now we
> have to use the developed neutron source for the measurement of nuclear
> reaction cross sections. So do we need to measure the neutron energy
> spectra experimentally, which seem to be very difficult because of its
> continuous nature. This spectrum involves from lower energy i.e 1 keV to
> higher energy up to 4 MeV. So to measure such spectrum we do not have
> detectors which will detects neutrons from 1 keV to 4 MeV energies. But we
> need to verify and validate this spectrum of neutron estimated through
> fluka with the experimental one.
> So my question is that "Is there any way on the basis of that we
> can believe on fluka results which directly validate with the
> experimental one ?"
> With regards
> Bhushan Patil
> Dr. Bhushankumar Jagnnath Patil
> Assistant Professor
> Department of Physics,
> Abasaheb Garware College,
> Pune - 411004

Alberto Fass
Received on Thu Jun 20 2013 - 11:01:19 CEST

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