Hi
Sorry I mis-red the position of the source.
Yes, if it is at x different from zero the symmetry is broken.
I would say that the two approaches you mention are equivalent
And, again, my sentence about solid angle was wrongly assuming a source on
the z axis.
Apologies
Paola
>
>
>
> From: "paola sala" <paola.sala_at_mi.infn.it>
> To: "Raksha Rajput" <rakshak_at_britatom.gov.in>
> Cc: fluka-discuss_at_fluka.org
> Sent: Friday, August 7, 2020 8:04:59 PM
> Subject: Re: [fluka-discuss]: Surface dose rate calculations
>
> Hello
> given that your geometry is cylindrically symmetric, I would suggest a
> cylindrical binning.
> Okay, noted.
>
> And, I do not see the need to have more than one bin in phi. Again, the
> geometry is phi-symmetric and the source is on the axis of the cylinder,
> there cannot be any phi-dependence in the results except for statistical
> fluctuations, and you'll gain a lot of statistics integrating over 2pi in
> phi.
> But if the source is placed at (4.6,0,0), the dose-Eq at x=
> -5.0445,y=0,z=0 will be different from that at x= +5.0445,y=0,z=0. Does
> this not imply the dependence of dose -eq on phi ? As I understand, phi
> varies from 0 to pi, from +X to-X via +Y and phi varies from 0 to -pi,
> from +X to -X via -Y. Hence the values are listed from -pi to +pi and I
> pick the bin value numbered 180th and 181st (from 360 bin values) to get
> the dose-Eq at x=+5.0445,y=0,z=0 (that is phi = 0.01744 rad and phi = -
> 0.01744 rad). Am I missing some point ?
>
> Then: do you want to score dose or dose-eq? I see two different quantities
> in the output files.
> Scored Dose-Eq. ('Dose' was written by mistake in SDUM, in one of the
> files).
>
> About the difference in statistics: if you score at z=0 in both cases,
> the solid angle will be different for the two cases, thus the statistics
> will be different.
> Thank you .
>
> Regards
> Paola
> Kindly clarify a little more. Thanks and regards,
> Raksha.
>
>
>
> Dear Experts,
>
> We have tried to calculate maximum surface dose rate on the surface of a
> SS cup (with center at (0,0,0) and outer radius 5.0445 cm) when the source
> is at (4.6,0,0).
>
> We tried this with Cartesian binning and R-phi-Z binning and scored
> DOSE-EQ.
>
> Please find attached the input files for 765.8 keV photon for both type of
> binnings and the results obtained (.lis fles).
>
> We would request you to comment on the correctness of the input and the
> results obtained.
>
> Can you please suggest which of the two binnings is advisable in our case
> ? Or, both can be used ?
>
> As we needed the dose rate at a point, we have reduced the volume of the
> bin to 1 mm^3 approx. - is this okay as the statistical errors seem less ?
> (We also found that when the source is at (0,0,0), the statistical errors
> seem to increase for 1 mm^3 binning detector, when compared to source at
> (4.6,0,0). We couldn't understand why. Please throw some light on this. )
>
> Kindly suggest any improvement to evaluate the dose rate at a point using
> FLUKA.
>
> Can you provide some example of using "special user defined 3D binning" in
> USRBIN ?
>
> Thanks and regards,
> Raksha Rajput.
>
>
>
>
>
>
>
>
>
>
> Paola Sala
> INFN Milano
> tel. Milano +39-0250317374
> tel. CERN +41-227679148
>
>
Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
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Received on Sun Aug 09 2020 - 17:16:46 CEST