Sabri Adila Hanim Aminordin, Abdul Aziz M Z, Olukotun S F, Tajudin S M
School of Medical Imaging, Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Terengganu, Malaysia.
Oncological and Radiological Science Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia.
J Med Phys. 2022 Jan-Mar;47(1):34-39. doi: 10.4103/jmp.jmp_86_21. Epub 2022 Mar 31.
Calculation of photon attenuation is necessary for the selection of shielding materials for an irradiation facility.
In this work, a Monte Carlo simulation was utilized to assess the effectiveness of clay-polyethylene mixture and clay as the radiation shielding materials for high-energy gamma sources (Ir-192). Ordinary concrete was also studied as the benchmark.
The calculated linear attenuation values for ordinary concrete are within 0.44% of the standard XCOM value for 380 keV photon. In the case of a multienergy Ir-192 gamma source, the calculated linear attenuation coefficient (μ) for ordinary concrete is 15.5% and 7.25% higher than clay and fabricated clay-polyethylene, respectively. Meanwhile, the μ value for fabricated clay-polyethylene is 8.3% higher than that of clay.
In conclusion, a 10 cm thickness of clay and clay-polyethylene mixture is sufficient to attenuate 87% and 89% of photons from Ir-192 source. The calculated linear attenuation coefficients for the three shielding materials are also consistently higher, about 7.5%, than that of the XCOM value for 380 keV photon.
计算光子衰减对于为辐照设施选择屏蔽材料是必要的。
在本研究中，利用蒙特卡罗模拟评估粘土 - 聚乙烯混合物和粘土作为高能伽马源（铱 - 192）辐射屏蔽材料的有效性。普通混凝土也作为基准进行了研究。
计算得出的普通混凝土的线性衰减值在380 keV光子的标准XCOM值的0.44%以内。对于多能铱 - 192伽马源，计算得出的普通混凝土的线性衰减系数（μ）分别比粘土和制成的粘土 - 聚乙烯高15.5%和7.25%。同时，制成的粘土 - 聚乙烯的μ值比粘土高8.3%。
总之，10厘米厚的粘土和粘土 - 聚乙烯混合物足以衰减来自铱 - 192源87%和89%的光子。三种屏蔽材料计算得出的线性衰减系数也始终比380 keV光子的XCOM值高约7.5%。
