海关官员 Mengsrom Song和他的同事早已习惯了辐射报警的声音。通过金边自治港的三分之一货物集装箱运输将在经过用于捕获走私辐射源和核材料的敏感门式辐射探测器时发出报警。
海关官员 Mengsrom Song和他的同事早已习惯了辐射报警的声音。通过金边自治港的三分之一货物集装箱运输将在经过用于捕获走私辐射源和核材料的敏感门式辐射探测器时发出报警。
但是，自该装置于2016年7月安装以来，所有报警都是由砖、肥料和建筑材料等材料引起的，位于柬埔寨首都金边郊外湄公河上的港口海关副局长 Song先生说。该港口处理着四分之一的柬埔寨对外贸易。
“评估辐射报警对我们来说是一个巨大的挑战，因为它们要求我们每天对几十个集装箱进行二次检查。”Song说。“这需要时间和资源，并影响我们的其他工作。” 二次检查需要花费时间使用手持式放射性核素识别 装置测量辐射量并确定其辐射类型与来源，还需要分析来自门式辐射探测器的数据，以检查商品的类型与来源。
一名海关官员在对经过港口发出辐射报警的卡车进行二次检查。通过手持设备证实，报警是由无害数量的钾-40同位素天然辐射引起的，而不是来自走私的放射源或核材料。（图/国际原子能机构 M. Gaspar）
国际原子能机构推出的一款新型智能手机应用程序将有助于区分由无害数量的天然辐射引起的报警与从安全角度可能引起关注并需要进一步调查的报警。
该应用程序是一项旨在改进初始报警评估的原子能机构协调研究项目的成果。原子能机构和20个国家的研究人员共同努力，通过开发探测软件的工具和算法改进报警评估过程，使其能够区分可能由走私的人造源引起的报警与由自然辐射引起的报警。
该应用程序可从iTunes和Google Play，Baidu下载。
这项研究的关键是能够区分这些不同物质的辐射特性，负责协调研究工作的原子能机构核安保官员Charles Massey说。这种区分不能以辐射量为基础，因为探测器需要捕获甚至可能存在的少量核材料或其他放射性物质。相反，研究人员要研究如何识别来自于表征每种材料的不同同位素的辐射构成。该软件将需要识别和记录这些特性，以便它能够屏蔽符合相同特性的天然材料产生的辐射。这样可以滤除大部分无害的报警，使海关官员集中精力处理其他不清楚的情况。
研究人员要研究新的算法，用于安装在监测系统的软件程序中。同时，这款被称为 “辐射报警和货物评价工具”（TRACE）的新应用程序提供了天然放射性物质及其典型辐射特性的详细概况。柬埔寨位于西哈努克最大的港口海关官员Sokkim Kreng说：“这是朝着正确方向迈出的重要一步，因为使用该应用程序将减少决定发出报警的集装箱是否需要进一步调查的时间。”
国际原子能机构导则建议，作为国家核安保计划的一部分，各国应使用辐射监测设备检查商品的进出口情况，以便拦截走私的核材料和放射性物质。
A customs officer performing a secondary inspection on a truck that set off the port’s radiation alarm. He is using a hand-held device. (Photo: M. Gaspar/IAEA)
A new smart phone application launched by the IAEA will help distinguish between alarms due to harmless amounts of naturally occurring radiation and alarms that might be a cause for concern from a security standpoint and warrant further investigation.
The app is the outcome of an IAEA coordinated research project that aims to improve the assessment of initial alarms. Researchers from the IAEA and 20 countries have worked together to improve the alarm assessment process by developing tools and algorithms for the detection software, with the goal of enabling it to distinguish between radiation from potentially smuggled man-made sources and naturally occurring radiation.
Download the app from iTunes and Google Play, or Baidu (for China).
The key to the research is to be able to distinguish between the radiation characteristics of these different substances, said Charles Massey, nuclear security officer at the IAEA, who coordinates the research. The distinction cannot be based on the quantity of radiation, because the detectors need to catch even small amounts of nuclear or other radioactive material that may be present. Instead, researchers are looking into ways to identify the make-up of radiation from different isotopes that characterize each material. The software will need to identify and record these, so that it can screen out radiation from naturally occurring materials that match these profiles. This would filter out most of the innocent alarms, allowing customs officers to concentrate on the remaining unclear cases.
Even while researchers are working on new algorithms for use in software programmes that will be installed in the detection systems, the new app called TRACE (Tool for Radiation Alarm and Commodity Evaluation) includes a detailed compendium of naturally occurring radioactive substances and their typical radiation characteristics. “This is a big step in the right direction, as using the app will reduce the time spent deciding whether a container setting of the alarm requires further investigation,” said Sokkim Kreng, customs officer at Cambodia’s largest sea port in Sihanoukville.
IAEA guidance recommends that countries use radiation detection equipment as part of their national nuclear security programmes to check commercial goods exports and imports, as a way to intercept smuggling in nuclear and radioactive material.