G4CMP error message

I was installed G4CMP library to simulate the electron-hole pair production.
I tried to execute an example using the command “/control/execute vis.mac” or “/run/beamOn 10” or "/run/initialize.
But the error popped up like this picture.
How can I fixed this error?!

Error Messeage

*** G4Exception : Lattice001
issued by : G4LatticeReader::MakeLattice
Unable to open Ge/config.txt
*** Fatal Exception *** core dump ***
**** Track information is not available at this moment
**** Step information is not available at this moment


Hello! Technically, G4CMP is not part of Geant4 :slight_smile:

The LatticeReader is looking for the data file that sets all of the parameters for phonons and charge carriers. In your G4CMP distribution, those are under the CrystalMaps/ directory. Once you source g4cmp_env.sh (or .csh, depending on your shell), that will set the $G4LATTICEDATA envvar and the reader will be able to find the files it needs.

It’s too late.
But I appreciate your help.
Thank you so much! :slightly_smiling_face: