USRBDX errors with zero as output

Hi, dear colleagues

I am running a simple simulation with 1 GeV of protons hitting a cylindrical block of water. I cut the water region with 2 planes and try to generate some spectrum plots at 4 different depth of the block with USRBDX.

The problem I ran into is that when I try to generate the plots. Error messages pop up in the output window say that all points y value undefined.

The attached is my input file and the error message. Let me know if you need any more info to determine what the problem is.

Thank you in advance.

1GeV_Protons_on_Water.inp (1.7 KB)

1GeV_Protons_on_Water001.err (22.4 KB)

Please ignore the typos in the comments, I have not amended them yet.

Dear Martin,

I checked your input file.
There is a geometry error. The WATER region overlaps with Tally1 and Tally2.

After fixing it, I was able to run it, and get the proton fluences, and plot them without an issue.

The .err file – beside the error messages – contains the normal progress report of FLUKA, showing how many particles has been simulated , how many left, time needed per particle, etc.

If you still have problems with plotting, please share your .flair project file as well (with that sharing the .inp is not necessary). It contains the information about the plots you want to do.


Dear David,

Thank you for your detailed the explanation. I fully understand what the problem is now.

However, just a quick question. So do I have to use cutplanes to divide the water block into more regions then use USRBDX if I want the spectrum at even more different depth? Seems a little bit repetitive, is there a better way of doing this?


Dear Martin,

In my opinion the easiest option is to add more cutting planes.

While there is an option to access the particle information at each simulation step with the mgdraw.f user routine, but it is considered an advanced feature. It requires fortran coding and post processing the recorded data manually.