Mazrou Hakim, Sidahmed Tassadit, Allab Malika
Centre de Recherche Nucléaire d'Alger (CRNA), Alger-RP, Algérie.
Radiat Prot Dosimetry. 2010 Sep;141(2):114-26. doi: 10.1093/rpd/ncq166. Epub 2010 Jun 16.
The main goal of the present work is to characterise the neutron field of an OB26 irradiation system acquired by the Nuclear Research Center of Algiers for radiation protection purposes. Extensive Monte-Carlo (MC) calculations and measurements using BF(3)- and (3)He-based neutron area dosemeters were performed to estimate the contribution, on the energy neutron spectrum, of each component present in the bunker facility of the Algerian Secondary Standard Dosimetry Laboratory (SSDL) where the irradiator has been installed. For this purpose, new irradiation configurations based on the (241)Am-Be source placed in the OB 26/2 biological shielding inside its environment have been investigated by MC simulations, and comparison with the ISO spectrum has been performed. During MC simulations, sensitivity analysis has been considered to estimate the effect of several physical parameters on the neutron fluence and dose equivalent rates. In addition, the contribution of the gamma dose equivalent rates to the total neutron dose equivalent rates was estimated for both selected source-detector distances (SDDs) 150 and 200 cm. Finally, a theoretical approach has been adopted, using MCNP5 fluence rates, to estimate the readings of the instruments taking into account their response functions. A low mean difference (12 %) between measured and predicted dose equivalent rates for two selected SDDs has been observed. Overall, the obtained MCNP5 results regarding the actual SSDL irradiation facility are particularly encouraging, but need to be supported by further experimental data.
本工作的主要目标是对阿尔及尔核研究中心为辐射防护目的获取的OB26辐照系统的中子场进行表征。使用基于BF(3)和(3)He的中子面积剂量计进行了广泛的蒙特卡罗（MC）计算和测量，以估计阿尔及利亚二级标准剂量学实验室（SSDL）掩体设施中存在的每个组件对能量中子谱的贡献，辐照器已安装在该实验室中。为此，通过MC模拟研究了基于放置在其环境内的OB 26/2生物屏蔽中的(241)Am-Be源的新辐照配置，并与ISO谱进行了比较。在MC模拟过程中，考虑了灵敏度分析以估计几个物理参数对中子注量和剂量当量率的影响。此外，针对选定的150和200 cm源-探测器距离（SDD），估计了γ剂量当量率对总中子剂量当量率的贡献。最后，采用了一种理论方法，利用MCNP5注量率，考虑仪器的响应函数来估计仪器的读数。在两个选定的SDD处，测量的和预测的剂量当量率之间观察到较低的平均差异（12%）。总体而言，关于实际SSDL辐照设施获得的MCNP5结果特别令人鼓舞，但需要进一步的实验数据支持。
