Hi Yann, thanks for this remark.
Actually I cannot reproduce the segmentation fault with the .dat Decay0 files we have in the repository. I used ‘packages/restG4/example/restG4Template/restG4.rml’. I tested with old and new Decay0 format, for example for new format <source use="Xe136bb2n.dat"/>, and for old format <source use="Xe136bb0n.dat"/>.
Could you please attach a reduced version of the decay0 file you are using.
I think for the moment only electrons and gammas are recognised using a pre-generated file, but we can adapt that. In addition, you may look to the following post, where there was some discussion about this topic. There is a new integration of ‘Decay0’, implemented by @nkx, that allows ‘online’ generation of events using Decay0.