ERROR: could not load neutron cross section

Dear experts,

After last version of FLUKA & flair updated on cluster, I did make a try with a test input based on “basic” template from flair calling Low-PWXS from JEFF library. The same file is running perfectly well on my lap top but on the cluster I get the following error message from .out file:
ERROR: could not load neutron cross section for isotope Z=6 A=12 m=0
Abort called from KHPNLOAD reason Error loading neutron cross section for isotope Run stopped!
STOP Error loading neutron cross section for isotope

From .log file I get this:
STOP Error loading neutron cross section for isotope
Note: The followinf floating-point exceptions are signalling: IEEE_UNDERFLOW_FLAG IEEE_DENORMAL

On both, FLUKA version is 4-3.3 and FLAIR version is 3.2-4.5
JEFF, ENDF and JENDL librairies are duly installed on /flukapath/data/neutron/ directory
I am not administrator on the cluster, so I did not install anything and I don’t know if there is any trick not explained on the librairies downloading page for a cluster installation.

On my laptop, the OS is from Ubuntu 20.04.5 LTS.
On the cluster it is

Ardi433.flair (2.7 KB)
Ardi433.inp (2.7 KB)
Ardi433001.log (175 Bytes)
Ardi433001.out (26.5 KB)

Any help will be greatly apprieciated.
Best regards,

Dear JB,

The input file you attached also run smoothly on my local machine with FLUKA 4-3.3 (the XS is properly loaded). I tried with both JEFF-3.3 1.0 and 1.1 versions.

Without being able to reproduce the error, it is tricky to tell:

  • Could you please look whether you have read access rights to /flukapath/data/neutron/JEFF-3.3 on your cluster machine?
    You can look, for example, for read rights to /flukapath/data/neutron/JEFF-3.3/Inelastic/CrossSection/6_nat_Carbon.z.
  • Which are the machines on your cluster?

Off-topic NB: The latest JEFF 3.3, ie version 1.1, is accessible from: FLUKA libraries for low-energy neutron pointwise interaction cross sections | The official CERN FLUKA website, where you can also find a description of the 1.0 → 1.1 update.


Dear Gabrielle,

Many thanks for your kind help. You got it! I have no read access rights for the librairies on the cluster…
I’m waiting for the correction and will try again as soon as possible.

Cluster machines are a combination of NEC HPC and NEC GPS, 13 nodes, 24 cores.

Best regards,

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