A buoy (shallow water light type) -based in situ gamma-ray spectrometry system with a 7.6 cmØ × 7.6 cm NaI(Tl) detector for remote real-time monitoring of gamma-ray emitting radionuclides in surface seawater is presented. To convert measured count rates to radioactivity, the full energy peak efficiency of the detector for radionuclides in seawater was estimated using Monte Carlo simulation with the MCNP code. The efficiency calibration was validated by comparing the results with a sampling analysis of ⁴⁰K in seawater at the sites where the monitoring systems were deployed. The minimum detectable activity of the system for ¹³⁷Cs, ¹³⁴Cs and ¹³¹I with gamma-ray measurement time is discussed.

提出了一种基于浮标（浅水光）的原位伽马射线光谱分析系统，该系统具有7.6cmØ×7.6 cm NaI（Tl）检测器，用于远程实时监测地表海水中的伽马射线发射放射性核素。为了将测量的计数率转换为放射性，使用带有MCNP代码的蒙特卡洛模拟法估算了海水中放射性核素检测器的全部能量峰值效率。通过将结果与部署监控系统的地点的海水中⁴⁰ K的采样分析进行比较，验证了效率校准。讨论了该系统在¹³⁷ Cs，¹³⁴ Cs和¹³¹ I下具有伽马射线测量时间的最小可检测活动。