Abstract
本研究針對氟化鈣(銩)熱發光劑量計(TLD-300),以我們所發展之推廣峰形法、Chen氏峰形法與依據 Levenberg -Marquardt法之計算程式，進行輝光曲線動力學參數分析。在 Co-60加馬射線與質子照射實驗中，質子照射後之樣品進行回火處理，以消除低溫峰。此外，本研究亦進行貯存時間與輻射品質(不同加馬射源照射)之實驗，探討其對熱發光動力學參數之影響。在加馬射線與質子照射實驗中，分析結果顯示，第五峰動力學次數介於 1與 2之間，與以前作者所宣稱的不同。照射後的回火處理對第三、五峰動力學參數之影響是顯著的。不同貯存時間實驗之計算結果顯示，第三、五峰動力學次數與陷阱深度漂移現象均非常明顯。在不同射源實驗中，其計算結果顯示，除了第三峰動力學次數保持不變外，光子有效能量對動力學次數與陷阱深度之影響是明顯的。推廣峰形法因使用較多實驗數據，可降低統計誤差。在鄰峰干擾不顯著的情況下，不同高度之推廣峰形法，其預估動力學參數的能力相當。但在鄰峰干擾顯著的情況下，隨著高度的增加，反而需要較精確的實驗數據，使得其推算動力學參數能力相對降低。但此一特性，在某些情況下可用來判斷鄰峰是否存在。此外，實驗輝光曲線是否遵循一般次動力學熱發光理論模式，可用推廣峰形法加以檢驗，此為Chen氏峰形法無法辦到。In the present study, peak shape method deve- loped byChen(1969) was generalized to arbitrary altitute (generalized peak shape method, GPS method). Kineticparameter analysis of CaF2:Tm (TLD-300) of proton andgamma-irradiated glow curves by means of the GPS method, theChen method and the Levenberg-Marquardt method were carriedout. The effect of post irradiation annealing on thekinetic parameters were also investigated. Besides, fadingand radiation quality effects (different photon-energiessources) on the kinetic parameters of dosimetric peaks werealso investi- gated. General order kinetics formula witha single energy level of traps was adopted as the fittingfunction in the Levenberg-Marquardt compu- tations. Theresults indicate that the kinetic order of peak 5 ofTLD-300 should be fractional (between 1 and 2) which isdifferent from first- order peak and second-order peak in thepreceding reports. The effects of post-irradiation annealing onthe kinetic parameters of dosimetric peaks are significant.In the different storage times and different photon sourcesexperiments, the results indicate that both fading andeffective photon en- ergies have pronounced influence on thekinetic parameters. The GPS method at altitute γIm (whereγ≦1, Im is peak maximum intensity) can be used to evaluatethe kinetic parameters of a given peak more precisely than thepeak shape method because more data points are involved.However, the predi- cted capability of kinetic parameters ofthe GPS method at altitute γIm is inferior to the Chenmethod as γ increases. On the other hand, this phenomenoncan be used to make a judgement whether a neighboring peakexists or not. Besides, GPS method can be used to testwhether a glow peak follows general-order kinetics.