光激螢光環境劑量計不確定度與最低可測限值評估

光激螢光環境劑量計（OSLD）具有可重複計讀、不需用電、維護簡易、不易受惡劣環境影響等優點，也符合各項劑量計基本特性的要求。但是計讀標準差與回火後殘餘劑量均較原使用的熱發光劑量計系統來的大，使得系統不確定度與最低偵測極限也都較高，無法達到目前最低偵測極限的要求。本文推導最低偵測極限估算的數學模式，規劃最簡單的改進方式為重複計讀4次以上的結果平均方能達到要求的最低偵測極限，此外，每季使用完後均要進行回火，藉以降低不確定度。以現有系統而言，田野測試結果顯示部分監測點差異過大但整體平均值相近，研判便是受到不確定度過高的影響所致，因此需採用多次量測，或請藍道爾公司進行儀器硬體調整以降低不確定度，方能應用於環境背景輻射劑量監測。

關鍵字

四維電腦斷層攝影；混合式治療技術；劑量體積圖；深吸氣閉氣技術

並列摘要

Optical stimulation luminescence dosimeter (OSLD) is passive, easy maintaining and environmental factors resistant that make it as a potential dosimeter for environmental monitoring. All the basic characteristic factors meet the requirements of environmental dosimetry. However, the reading standard deviations and residual doses after annealing are higher than those of thermoluminescence dosimeters (TLD) used now. These also enlarge the detection limit. By the mathematic model derived in this work, more than four repeated readings and annealed every time to reduce uncertainty is necessary to meet the requirement of lower limit of delectability. The field test results show that the differences between OSLDs and TLDs are due to uncertainty. It is suggest that application of OSLD for environmental monitoring should carefully deal with uncertainty to lower the detection limit.

並列關鍵字

Optical Stimulation Luminescence ； Dosimetry ； Lower Limit of Delectability

國際替代計量

光激螢光環境劑量計不確定度與最低可測限值評估

全文下載

主題瀏覽