Hasan Md Moudud, Rutten Jos, Camps Johan, Huysmans Marijke
SCK CEN, Belgian Nuclear Research Centre, Boeretang 200, BE-2400, Mol, Belgium; Department of Hydrology and Hydraulic Engineering, Vrije Universiteit Brussel (VUB), Pleinlaan 2, BE-1050, Brussels, Belgium.
SCK CEN, Belgian Nuclear Research Centre, Boeretang 200, BE-2400, Mol, Belgium.
Appl Radiat Isot. 2022 Jul;185:110247. doi: 10.1016/j.apradiso.2022.110247. Epub 2022 Apr 16.
A 3.81 × 3.81 cm LaBr(Ce) detector based portable measurement setup has been developed for in situ gamma spectrometric survey of a contaminated site. This system is suitable for above- and below ground surface gamma spectrometric measurements of Cs. However, the minimum detectable activity concentration (MDAC), an important parameter of a measurement system, should be estimated for planning purposes of the gamma spectrometric survey. In this study, the MDAC of Cs for the measurement setup was investigated. The efficiency of the measurement setups was calculated from Monte Carlo simulations using MCNP code. The numerical model of the different studied set-ups, used in MCNP, performed well for the known cases. The results show that the MDAC varies with the position of the detector with respect to ground surface. A 5-20 min acquisition time, depending on the detector position, can be sufficient to get a MDAC of about 10% of the exemption limit of Cs (100 Bq/kg).
已开发出一种基于3.81×3.81厘米溴化镧（铈）探测器的便携式测量装置，用于对受污染场地进行现场伽马能谱测量。该系统适用于对铯进行地面及地下伽马能谱测量。然而，为了伽马能谱测量的规划目的，应估算测量系统的一个重要参数——最低可探测活度浓度（MDAC）。在本研究中，对该测量装置的铯MDAC进行了研究。测量装置的效率通过使用MCNP代码的蒙特卡罗模拟计算得出。MCNP中使用的不同研究装置的数值模型在已知情况下表现良好。结果表明，MDAC随探测器相对于地面的位置而变化。根据探测器位置，5 - 20分钟的采集时间可能足以获得约为铯豁免限值（100贝克勒尔/千克）10%的MDAC。
