Fully Geant4 compatible package for the simulation of Dark Matter in fixed target experiments

We present the package for simulation of DM (Dark Matter) particles in fixed target experiments. The most convenient way this (and only possible case beam-dump) is to simulate it framework program tracing experimental setup. One popular such programs Geant4. Specifically, includes processes production via electron and muon bremsstrahlung off nuclei, resonant in-flight positron annihilation on atomic electrons gamma ALP (axion-like particles) conversion nuclei. Four types mediator are considered: vector, scalar, pseudoscalar axial vector. In particular, total cross sections calculated at exact tree level (ETL). code handles both invisible decay visible into $e^+e^-$ (or $\gamma \gamma$ ALP). software consists a collection different classes, inheriting from Geant4 thus expected use include Geant4-based propagation interaction detector. As an example its usage, we discuss results obtained typical active beam-dump experiment, considering $5 \times 10^{12}$ 100 GeV impinging lead/plastic scintillator thick target, showing sensitivity four mentioned above.