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

在世界各地，由于核电、医疗程序、核武器的使用增加，以及影响日本福岛等发电厂的自然灾害，辐射暴露一直在上升。增加辐射暴露对人体有短期和长期的有害影响，对辐射吸收剂量的快速诊断(分诊)对生存至关重要。因此，在不增加额外硬件或处理设备开销的情况下，拥有快速、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。该项目将开发一种使用商用闪存芯片的手持实时辐射剂量测量解决方案。由于存储芯片广泛应用于许多嵌入式系统(如智能手机)和可穿戴设备(如健身腰带)，该项目的概念可以通过分布式智能设备提供辐射剂量测量的范式转变，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，该项目具有强大的教育成分，包括培训未被充分代表的学生，让本科生参与研究，并将该项目的研究成果纳入课程。该项目的目标是利用商用闪存的误码率开发一种新的具有成本效益的辐射剂量计技术。剂量学解决方案将提供吸收剂量值的实时读出，这是快速诊断应用程序的理想选择，以最大限度地减少那些工作在离辐射环境更近的人的健康风险。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，以在更大范围内提供更好的态势感知。该项目利用橡树岭国家实验室的仪器和专业知识，通过一系列辐射曝光实验来证明基于闪存的剂量测量概念的有效性。将进行建模和实验，以确定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)电离辐射通过芯片的线金属层的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，这项研究促进了我们对半导体器件辐射-物质相互作用和与辐射相关的可靠性物理的认识。这项研究还将实现无线、被动、现场、实时的辐射剂量测量解决方案，该解决方案可针对包括人员剂量测量、安全、空间和商业应用在内的广泛应用进行定制。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.