Experimental investigation of gamma-ray attenuation and effective atomic parameters of selected polymeric materials

The development of lightweight, flexible, and non-toxic radiation shielding materials has become increasingly important for modern medical, industrial, and portable radiation applications, where conventional shielding materials pose limitations. In the present study, gamma-ray attenuation behaviour and photon interaction characteristics of seven low-Z polymers—Polyisobutylene (PIB), Poly (vinyl acetate) (PVAc), Poly (methyl acrylate) (PMA), Poly (tetrafluoroethylene) (PTFE), Poly (methyl methacrylate) (PMMA), Poly (phenylene sulfide) (PPS), and Poly (ethyl methacrylate) (PEMA)—have been systematically investigated over the photon energy range of 122–1330 keV using a NaI(Tl) detector under narrow-beam geometry. The experimentally determined mass attenuation coefficients (µ/ρ) and derived parameters, including total atomic cross-sections (σt), electronic cross-sections (σe), effective atomic numbers (Zeff), effective electron densities (Neff), and molar extinction coefficients (ε), provide detailed insight into photon–matter interaction mechanisms within polymeric systems. The observed decrease in µ/ρ, σt, and σe with increasing photon energy reflects the reduced probability of photon absorption and the growing dominance of Compton scattering in the intermediate energy region. Similarly, the variation in Zeff and Neff indicates that photon interaction is strongly governed by the effective electron distribution and elemental composition of the polymers. Polymers containing relatively higher atomic constituents, such as fluorine and sulfur in PTFE and PPS, exhibit comparatively enhanced attenuation behavior, highlighting the role of molecular composition in radiation shielding efficiency. The experimental results are in good agreement with theoretical predictions, confirming the reliability of the measurements. This study establishes a comprehensive experimental understanding of structure-dependent radiation interaction in pure polymers, providing a scientific basis for the design of efficient, low-cost, and environmentally safe polymer-based shielding materials.