Wireless Miniature Dosimeters for In-Situ Radiation Measurement

智能优点：这项传感器提案侧重于开发一种用于无线就地辐射剂量测量的新型微型应答器。建议的传感器是完全无源的，即不需要板载电源，从而避免了与有源电子设备(晶体管等)辐射损坏相关的问题。该应答器基于一种新型的器件结构，它将驻极体产生的准永久电场与硅微机械加工结合在一起。微机械LC剂量计结合了一组悬臂梁，通过驻极体产生的电场偏转。该阵列连接到片上螺旋线圈，从而形成无源LC谐振电路。当暴露在电离辐射下时，驻极体的表面电荷减少，从而减小了对悬臂梁的力(从而减小了它们的偏转)。这降低了梁和驻极体底部电极之间的电容，这可以通过监测LC应答器的谐振频率来远程检测。更广泛的影响：将无线技术与微型剂量计结合使用进行辐射测量的能力将在许多领域提供宝贵的工具，如放射治疗、人员和环境监测。这项研究的成果将导致一系列具有成本效益的小型无线就地辐射传感器。在此项目过程中开发的技术还将对许多需要将驻极体与MEMS微结构(例如机电换能器、粒子过滤器和红外传感器)集成的应用和设备产生广泛影响。

Intellectual Merit: This sensor proposal focuses on the development of a novel microtransponder for wireless in-situ radiation dosimetry. The proposed sensor is totally passive, i.e., do not require an on board power source, and thus avoid problems associated with radiation damage to active electronics (transistors, etc). The transponder is based on a novel device structure combining the quasi-permanent electric field produced by an electret with silicon micromachining. The micromachined LC dosimeter incorporates an array of cantilever beams deflected by the electric field produced by an electret. This array is connected to an on-chip spiral coil, thereby forming a passive LC resonant circuit. Upon exposure to the ionizing radiation, the surface charge of the electret is reduced hence decreasing the force on the cantilever beams (and therefore decreasing their deflection). This decreases the capacitance between the beams and the bottom electrode of the electret, which can be detected remotely by monitoring the resonant frequency of the LC transponder. Broader Impact: The ability to use wireless techniques for radiation measurement in conjunction with a miniature dosimeter will provide a valuable tool in many areas such as radiation therapy, personnel, and environmental monitoring. The out come of this research will lead to a family of cost effective, small sized wireless in-situ radiation sensors. The techniques developed during the course of this project will also have a broad impact on many applications and devices that require the integration of electrets with MEMS microstructures (e.g., electromechanical transducers, particle filters, and infrared sensors).