The .py files end with "fin" or "final" are finalized scripts. file_txt_to_npy.py is used to convert txt file to binary file. The .npy file can be used in the write_gamma_simulation_1.4_fin.py. The step may be like: file_txt_to_npy.py -----> write_gamma_simulation_1.4_fin.py -----> dataloader_Doubles_neutron_simulation_v2 -----> Backprojection_MCNP_gammas_2_final.py