Abstract: Significant radiations in the frequencies ranging from gamma rays and X-rays to radio frequency can be generated during the interactions between powerful lasers with solid targets. Gamma rays are able to penetrate metal walls of diagnostic setups and induce secondary electrons, which can further radiate Electromagnetic Pulses (EMPs). In this study, emissions of secondary electrons due to gamma-metal interactions are quantitatively simulated. The results indicate that secondary ions are strongly pertinent to the incident Gamma rays, metal contents and metal shapes. The Maxwell’s equations confirm that electromagnetic pulses partially stem from the secondary charges, and its average energy and spatial distribution are also discussed. The resulting conclusions are beneficial to deepen understanding of EMP generations and also offer more experimental supports to achieve an effective shielding design for various physical diagnostics.