RE: [fluka-discuss]: USRBIN 1D-Projection

From: Eleftherios Skordis <>
Date: Tue, 19 Dec 2017 20:08:35 +0000

Dear Patryk,

the reason for the discrepancy is that you are not taking into account that in cylindrical coordinates the R-Phi bins do not have identical surface area, while the phi-Z bins do.
That's why your way of processing the data works when projecting in R and not when projecting in Z.
For example if you have 4 GeV/cm^3 in an external R bin and 2 GeV/cm^3 in an internal R bin, you cannot assume that the average is 3 since they correspond to different volumes even if they have the same R bin size.

Try to normalise according to the volume (surface is enough in this case) of the bins.
E.g. multiply each bin value with the bin surface in R-Phi. This will give you results per cm (e.g. GeV/cm). Add them together and then divide by the total cross-sectional area (i.e. pi*Rmax^2) for each Z.

This should give the proper results

Hope this helps

Kind regards



Eleftherios Skordis
CH-1211 GENEVA 23

OFFICE: +41-22-7679541

From: [] on behalf of Patryk Pasterny []
Sent: 19 December 2017 16:47
Subject: [fluka-discuss]: USRBIN 1D-Projection

ar FLUKA users,

I have a question about projecting USRBIN in R-Phi-Z coordinate system on Z axis.
I am using bnn.lis files to convert USRBIN data into .root TH3D histo. When i want to project this data to 1D histogram on R axis i sum up data for all data from Phi and Z bins for each R, dividing the result by (number of bins Phi * number of bins Z) and then fill TH1F histo with it. When i am comparing it with FLAIR-gnuplot histogram they are exactly the same. The problem occurs when i want to do the same, but project it on Z axis. I understand that i should remember that i am in R-Phi-Z coordinate system so i use equation in attachment to count it (r is in my programm the center of bin). I am getting close but not equal values for each bin in Z shown in attachment also. Do you know how exactly gnuplot make 1D-Projection on Z axis
for USRBIN card, or maybe it is just a problem of precision of numbers used in FLAIR and in my program?

Patryk Pasterny

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Received on Tue Dec 19 2017 - 22:15:21 CET

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