Indian Journal of Chemical Technology Vol. 26, July 2019, pp. 347-350 A comparatıve study on shielding properties of some composite materials by MCNPX code Huseyin Ozan Tekin* ,1,3 , Elif Ebru Altunsoy 2,3 , V P Sıngh 4 , Umit Kara 5 & Iskender Akkurt 6 1 Uskudar University, Vocational School of Health Services, Radiotherapy Department, Istanbul 346 72, Turkey. 2 Uskudar University, Vocational School of Health Services, Medical Imaging Department, İstanbul 346 72, Turkey. 3 Uskudar University, Medical Radiation Research Center (USMERA), Istanbul, 346 72, Turkey. 4 Department of Physics, Karnatak University, Dharwad 580 003, India. 5 Suleyman Demirel University, Vocational School of Health Services, Medical Imaging Department, Isparta, Turkey. 6 Suleyman Demirel University, Faculty of Arts and Science, Physics Department, Isparta, Turkey. E-mail: huseyinozan.tekin@uskudar.edu.tr Received 20 February 2019 ; accepted 2 April 2019 The radiation mass attenuation coefficients of composite material samples as shielding materials have been calculated at 356, 511, 662, 1173, 1274 and 1332 keV photon energies by using general purpose Monte Carlo code MCNPX (version 2.6.0). The obtained numerical results agree well with experimental and standard XCOM data. As a result, the maximum values of mass attenuation coefficients are found for D1 and D2 composite material samples. It can be concluded that, new generation composite materials can be alternative shielding materials against gamma-ray radiation and Monte Carlo method can be employed for similar material investigations as an alternate tool for assessment. Keywords: Mass attenuation coefficients, Polymer composites, Monte Carlo The use of different types of materials for shielding applications is increasing day-by-day for industries, agriculture, space, medical, reactors, accelerators, etc, for reduction of exposure to occupational worker, patient, etc. The choice of shielding materials is highly dependent upon the requirement for exposure rate reduction, type of source, space constrains and final cost effective analysis. Nowadays, lead is common and very useful material in the field of nuclear engineering for shielding applications. However, the toxic properties and cost of lead have led to the investigation of alternative shielding materials and various investigations and products are readily available. The polymer composite materials which are harmless to the environment and non-toxic are suitable alternate with both personal and material shielding, efficiently. In general, experimetal studies requires not only materials, radiation sources and experimental setup of very high financial budget but also radiation exposure to involved personnel. However, mathematical simulation methods for investigation of radiation interaction is found less time consuming, radiologically safer, cost suitable and applicable for desired energy of radiation. It is found that, Monte Carlo simulation is suitable method for investigation of radiation interaction with materials in various literature elsewhere 1-11 . The radiation mass attenuation coefficient is basic property of a material for photon interaction to indicate interaction and shielding effectiveness. The mass attenuation coefficient of an element is found to be constant at particular photon energy, while mass attenuation coefficient of a compound or mixture depends upon chemical composition of elements 12 . On the other hand, another radiation shielding parameters such as the linear attenuation coefficient, half-value layer thickness (HVL), tenth-value layer (TVL) thickness and effective atomic number (Z eff ) are derived parameters from the mass attenuation coefficient. Previously, the shielding parameters of recent composite materials has been studied by Erol et al. 13 . But the computational simulation studies for photon interaction couldn’t be found in the literature. This has encouraged us to set a simulation setup to investigate the attenuation properties of those materials and validate the MCNPX (version 2.6.0) code. Therefore, this study aimed to investigate the mass attenuation coefficients of different types of composite materialsusing MCNPX (version 2.6.0) code at 365.5, 511, 661.6, 1173.2, 1274 and 1332.5