RII Track-4: Real-Time Radiation Dosimetry Using Flash Memory

在世界各地，由于核能、医疗程序、核武器的使用增加以及影响核电站（如日本福岛）的自然灾害，辐射暴露一直在上升。增加的辐射暴露对人体有短期和长期的有害影响，对吸收的辐射剂量进行快速诊断（分诊）对生存至关重要。因此，在不需要额外硬件或处理设备的情况下，拥有一种快速、经济高效且可现场部署的个人剂量测量解决方案至关重要。该项目将开发一种手持式实时辐射剂量测定解决方案，使用市售的闪存芯片。由于存储芯片广泛用于许多嵌入式系统（例如智能手机）和可穿戴设备（例如健身带），因此该项目的概念可以通过分布式智能设备为辐射剂量学提供范式转变，这将对健康监测、遥感、军事应用、核反应堆安全和空间应用非常有用。此外，该项目具有很强的教育成分，包括培训代表性不足的学生，让本科生参与研究，并将项目的研究成果纳入课程作业。该项目的目标是开发一种新型的具有成本效益的辐射剂量计技术，利用商用闪存的误码率。剂量测定解决方案将提供吸收剂量值的实时读数，这是快速诊断应用的理想选择，以尽量减少那些工作在辐射环境附近的人的健康风险。该技术还可以促进无线传感器网络（例如，通过智能手机），并将数据传输到中央设施，以在更大的区域内提供更好的态势感知。该项目利用了橡树岭国家实验室的仪器和专业知识，通过一系列的辐射暴露实验来证明基于闪存的剂量学概念的有效性。将进行建模和实验，以确定所建议的剂量计的工作范围，并提高其准确性、灵敏度和选择性。此外，我们提出了新的测量技术，以了解和量化(i)电离辐射穿过芯片线金属层后端时的剂量增强效应，（ii）入射辐射束对存储器的方向性效应，以及（iii）闪存阵列中的电离与位移损伤效应。因此，本研究提高了我们对半导体器件辐射-物质相互作用和辐射相关可靠性物理的认识。该研究还将实现无线、无源、原位、实时辐射剂量测定解决方案，该解决方案可定制用于广泛的应用，包括人员剂量测定、安全、空间和商业应用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Throughout the world, radiation exposure has been on the rise due to the increased use of nuclear power, medical procedures, nuclear weapons and natural disasters affecting power plants such as in Fukushima, Japan. Increased exposure to radiation has both short- and long-term detrimental effects on the human body and rapid diagnosis (triage) of an absorbed dose of radiation is critical for survivability. Thus, it is critical to have a fast, cost-effective and field-deployable personal dosimetry solution without the overhead of additional hardware or processing equipment. The project will develop a handheld, real-time radiation dosimetry solution using commercially available flash memory chips. Since memory chips are widely used in many embedded systems (e.g., smartphones) and wearable devices (e.g., fitness belts), this project’s concept could provide a paradigm shift in radiation dosimetry through distributed smart devices, which will be very useful for health monitoring, remote sensing, military applications, nuclear-reactor safety and space applications. In addition, the project has a strong educational component that includes the training of underrepresented students, the involvement of undergraduate students in research and the incorporation of the project's research findings into coursework.The objective of this project is to develop a novel cost-effective radiation-dosimeter technology using the bit error rate of commercial flash memory. The dosimetry solution will provide real-time read-out of absorbed dose value, which is ideal for rapid diagnosis applications to minimize health risk for those who work closer to radiation environment. The technology can also facilitate a wireless sensor network (e.g., through smartphones), and transmit data to a central facility to provide better situational awareness over a larger area. The project takes advantage of the instrumentation and expertise at Oak Ridge National Laboratory to demonstrate the validity of a flash memory-based dosimetry concept through a series of radiation-exposure experiments. Both modeling and experimentation will be performed to determine the range of operation of the proposed dosimeter and to enhance its accuracy, sensitivity and selectivity. In addition, we propose novel measurement techniques in order to understand and quantify the (i) dose-enhancement effect when ionizing radiation goes through the back end of the line metal layers of a chip, (ii) directionality effects of the incident radiation beam on the memory and (iii) ionization vs. displacement damage effect in the flash-memory array. Thus, this research advances our knowledge on the radiation-matter interaction and the radiation-related reliability physics of semiconductor devices. The research will also enable a wireless, passive, in-situ, real-time radiation-dosimetry solution that can be customized for a wide range of applications including personnel dosimetry, safety, space and commercial applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.