In the current study, the epoxy material was mixed with 10%, and 30% weight percent carbon material as filler in different thicknesses (1 cm, 1.5 cm, and 2 cm). Transmission electron microscope (TEM) measurements showed the average size of the nano-carbon was 20 nm with a standard deviation of 5 nm. The morphology of samples was examined using scanning electron microscopy (SEM), which showed the flatness of the epoxy surface, and when the content of carbon increases, the connection between the epoxy array and carbon increases. The compression test indicates the effect of nano-size on enhancing the mechanical properties of the studied samples. To survey the shielding properties of the epoxy/carbon composites using gamma-rays emitted from Am-241, Ba-133, Cs-137, Co-60, and Eu-152 sources, which covered a wide range of energies from 0.059 up to 1.408 MeV, the gamma intensity was measured using the NaI (Tl) detector. The linear and mass attenuation coefficients were calculated by obtaining the area under each peak of the energy spectrum observed from Genie 2000 software in the presence and absence of the sample. The experimental results obtained were compared theoretically with XCOM software. The comparison examined the validity of experimental results where the relative division rate ranged between 0.02 and 2%. Also, the measurement of the relative division rate between linear attenuation coefficients of microand nano-composites was found to range from 0.9 to 21% The other shielding parameters are calculated at the same range of energy, such as a half-value layer (HVL), mean free path (MFP), tenth-value layer (TVL), effective atomic number (Zeff), and the buildup factors (EBF and EABF). The data revealed a consistent reduction in the particle size of the shielding material across various weight percentages, resulting in enhanced radiation shielding capabilities. The sample that contains 30% nano-carbon has the lowest values of TVL (29.4 cm) and HVL (8.85 cm); moreover, it has the highest value of the linear attenuation coefficient (LAC), which makes it the best in its ability to attenuate radiation.

Comparative study between micro- and nano-carbon with epoxy for gamma shielding applications
    Abstract
    1 Introduction
    2 Materials and method
        2.1 Materials and sample preparation
            2.1.1 Morphology
                2.1.1.1 Mechanical measurements 
            2.1.2 Attenuation parameters
    3 Results and discussion
        3.1 Microstructure analysis
        3.2 Mechanical measurements
        3.3 Attenuation calculation
    4 Conclusion
    References

• Mona M. Gouda(Physics Department, Faculty of Science, Alexandria University, Alexandria 21511, Egypt) Corresponding author
• Ahmed M. El‑Khatib(Physics Department, Faculty of Science, Alexandria University, Alexandria 21511, Egypt)
• Mona M. Khalil(Physics Department, Faculty of Science, Alexandria University, Alexandria 21511, Egypt)
• Mohamed Abd‑Elzaher(Department of Basic and Applied Sciences, Faculty of Engineering, Arab Academy for Science, Technology and Maritime Transport, Alexandria, Egypt)
• Mahmoud I. Abbas(Physics Department, Faculty of Science, Alexandria University, Alexandria 21511, Egypt)