Dear Jyoti,
your theoretical expectation holds if one neglects the electron transport.
To convince yourself, raise the electron threshold (EMFCUT) and you will
find your number back. Still, low thresholds imply better accuracy.
Note also that you can significantly improve your statistics by covering
with your detector region the whole solid angle. Instead of a small sphere
1 m aside, take a spherical layer centered in the origin with radius
around 1 m (e.g. between 99 and 101 cm) and properly normalize with its
volume.
Best wishes
Francesco
**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. +41 22 7678962
On Sat, 1 Dec 2018, Jyoti wrote:
> Dear Francesco,
> For 1 Ci Co-60 source (energy 1.17 MeV), I run the program.
> Radius of detector: 5cm
>
> The energy deposited is 6.5E-11 and % error is 6.2%.
> The dose calculated from this energy deposited is 0.23 R/h.
>
> I am calculating dose form the energy value obtained in 21 card and trying
> to compare this value with the theoretical one.
> The theoretical dose is calculated using the formula (0.52CE/r^2) R/h where
> E is in MeV, r is in m and C is in Ci. (Here for E=1.17 MeV, theoretical
> dose is 0.61 R/h).
>
> Kind Regards
>
> Jyoti
>
>
> On 11/30/18 09:44 PM, Francesco Cerutti <Francesco.Cerutti_at_cern.ch> wrote:
>
> Dear Jyoti,
>
> first, note that you do not need a source routine for an
> isotropic distribution, which is simply available through the
> BEAM card (WHAT(3)).
>
> Second, what you score in the unit 21 is the energy *deposited*
> in your detector made of *air* (GeV per emitted photon), while
> in unit 22 you get a 3D distribution of energy density deposited
> in air (GeV/cm3 per emitted photon). In principle there is
> nothing wrong in all that, the point is what you want to compare
> to, and how you normalize the resulting number.
>
> Kind regards
>
> Francesco
>
> **************************************************
> Francesco Cerutti
> CERN-EN/STI
> CH-1211 Geneva 23
> Switzerland
> tel. +41 22 7678962
>
> On Thu, 29 Nov 2018, Jyoti wrote:
>
> >Dear FLUKA experts
> >I took a Co-60 point source at (0,0,0) and a spherical detector
> at 100 cm.
> >Energy: 1.17 MeV, one photon
> >Then I run the file, the result is not even close to the
> theoretical predicted value.
> >
> >Kindly find the source and input file attached.
> >Please let me know the error.
> >
> >With Regards,
> >Jyoti
> >
> >
>
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Received on Sat Dec 01 2018 - 20:15:17 CET