RADIOLOGICAL IMPACT OF USING DECORATIVE GRANITE AS AN ATTENUATOR OF IONIZING RADIATION.

This article evaluates the natural radioactivity and radiation shielding properties of granite samples commonly used as decorative building materials in Korea. Using a high purity germanium (HPGe) detector, the study measured activity concentrations of radionuclides ^226Ra (radium-226), ^232Th (thorium-232), and ^40K (potassium-40), finding values below or near international safety limits set by UNSCEAR. Radiological hazard indices—including radium equivalent concentration (Ra_eq), external (H_ex) and internal (H_in) hazard indices, alpha and gamma indices, and annual effective dose—were all within recommended safe levels, indicating no significant radiation risk from these granites. Additionally, the mass attenuation coefficients and half-value layers of the granite samples were measured across gamma-ray energies from 122 to 1408 keV, showing attenuation characteristics comparable to concrete, supporting granite's potential use as a natural shielding material against ionizing radiation in construction and medical settings.