Development of a new optical fiber sensor for radiation and chemical parameters with sensing regions in its cladding

目前用于测量辐射的闪烁光纤存在本征损耗和辐射诱导损耗较高的缺点。为了克服这些问题，人们提出了一种新型的多点辐射测量光纤传感器，在其包层内和芯外区域设置了敏感区。闪烁材料由聚苯乙烯、PPO和POPOP组成。一部分闪烁光子被捕获在光纤芯内，并被传输到末端。将飞行时间技术应用于传输到各光纤端的光子到达时间差。时间分辨率为4毫微秒的离散辐射测量是可能的。测量的计数在4.2Sv至44μSv的剂量率范围内具有良好的线性关系。目前的问题之一是系统难以控制测量效率和传感点处的传输损耗，这应该是由于传感区域的制造过程中涉及的机械过程。化学过程将是解决这一问题的候选方法。通过参数研究选择最佳配置，可以改善传感系统的性能。

Current scintillating optical fibers for the measurement of radiation have drawbacks concerning high intrinsic and radiation-induced loss. In order to overcome these problems, a new optical fiber sensor for multi-point radiation measurements has been proposed with sensing regions in its cladding and in the area outside of the core. Scintillation material was composed of polystyrene, PPO, and POPOP. A part of the scintillation photons is trapped inside the fiber core and is transmitted to the ends. The time of flight technique has been applied to the arrival time difference of the photons which are transmitted to each fiber end. Discrete radiation measurements were possible with a time resolution of 4nsec. Linearity of the measured counts has been demonstrated in a dose rate ranging between 4.2μSv to 44μSv. One of the present problems regards the system's difficulty in controlling the measurement efficiency and the transmission loss at the sensing points, which should be due to the mechanical process involved in the fabrication of the sensing regions. A chemical process will be a candidate for the solution of this problem. By choosing the best configuration based on parameter studies, the properties of the sensing system can be improved.