Background: The present study aimed to determine half-value layers (HVL) of different materials with neutron, photon, and simultaneous neutron and photon emissions by a ²⁵²Cf source. MCNPX code was used for the simulation of the applicator tube (AT) ²⁵²Cf source and the attenuation materials. Materials and methods: The ²⁵²Cf source, a source collimator, a detector, a detector collimator, and HVL material were defined in the present study. HVL was determined for lead, concrete, water, polyethylene, and polyethylene mixtures with various concentrations of boric acid for separate neutron, separate photon, and simultaneous emissions of neutron and photon by the ²⁵²Cf source. Results: HVL values were tabulated for the aforementioned materials for separate neutron, separate photon, and for simultaneous neutron and photon emissions by the ²⁵²Cf source. Among the evaluated materials, polyethylene was the most adequate material for neutron shielding. Conclusion: The obtained HVL results for different materials could be used for shielding design around a ²⁵²Cf source. According to the comparison of lead with concrete, lead was a suitable material for shielding against the photons emission. On the other hand, concrete with a lower HVL value seemed to be superior for neutron shielding. The combination of several HVL layers of polyethylene and lead could result in proper shielding against neutron and photon. In simultaneous neutron and photon emissions, the emitted neutrons from the source generate secondary photons. The issue led to increase HVL, and could be considered in the protection and shielding against the source.