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題 名 | 熱發光劑量計對質子的回應=Thermoluminescent Response for Proton |
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作 者 | 林松彥; 林招膨; 朱鐵吉; 徐竹村; 劉幕臺; 葉啟源; | 書刊名 | 放射治療與腫瘤學 |
卷 期 | 5:2 1998.06[民87.06] |
頁 次 | 頁135-142 |
分類號 | 416.36 |
關鍵詞 | 熱發光劑量計; 質子加速器; 直線能量轉移; 輝光曲線; 徑跡結構理論; 深陷阱競爭模型; Thermoluminescent dosimeter; Cockroft-walton accelerator; Linear energy transfer; LET; Glow curve; Track structure theory; TST; Deep trap competition model; |
語 文 | 中文(Chinese) |
中文摘要 | 目的:瞭解熱發光劑量計對低能量質子的回應,以供將來建立布拉格尖峰處劑量 量測技術所需。 材料與方法:將以最佳回火條件回火完成之CaF□:Dy(TLD-200)及CaF□:Tm(TLD-300), 確保其表面性質及真空回火後冷卻過程對熱發光反應無影響後,將其置於真空腔內之一壓克 力置裝器內。由Cockroft-Walton加速器提供之質子源,能量在30-100keV間,經準直後通 過一10μg/cm□之碳膜做拉塞福散射(Rutherford scattering),散射後之質子均勻打在置 於其後20°的壓克力置裝器內的熱發光劑量計,利用壓克力置裝器後之一電子倍增器 (channeltron)作為量測質子工具。照射完之熱發光劑量計經計讀後分析輝光曲線與質子能 量之關係。 結果:TLD-200、TLD-300照射30-100keV質子,結果顯示TLD-200、TLD-300熱發光靈 敏度隨質子能量下降(直線能量轉移(linear energy transfer, LET)下降)而上升,符合徑 跡結構理論(track structure theory, TST)。而TLD-300之輝光曲線分析,亦證明其符合 深陷阱競爭模型之推論(deep trap competition model)。同時其各輝光峰(第二、第三、第 五輝光峰)與質子能量具相關性。 結論:研究結果顯示,TLD-200、TLD-300有足夠的靈敏度可作為量測質子劑量使用,唯 其並非組織等效材料,需經一些校正因數修正,同詩尚需更多不同能量質子的靈敏度校正因 數的量測配合,方可使質子劑量量測技術更為完整準確。 |
英文摘要 | Purpose: To understand the TLD response for low energy proton in order to establish the proton dose measurement technique at Bragg peak in the future. Materials and Methods: Under the best annealing condition treatment and making sure the surface characteristics and cooling process after vacuum annealing had no significant effects to thermoluminescent response. TLD samples were put into the ABS TLD holder in the vacuum chamber. Proton generated from a Cockroft-Walton accelerator in the energy range of 30-100 keV were appropriately collimated and made to pass through a 10 μg/cm□ carbon foil. After Rutherford scattering, proton uniformly irradiated TLDs which were placed at the 20° behind and 20 cm away from the carbon foil. We used a channeltron behind TLD holder as the proton detector. After irradiation, readout of the TLD samples was done with a TLD reader and comparison of the glow curve under different proton energies was initiated. Results: The result showed that the TLD-200, TLD-300 sensitivities increased while proton energy decreased (LET decreased), which was consistent with track structure theory. While TLD-300 glow curve analysis conformed to the deep trap competition model, it also showed that the glow peaks (P2, P3, P5) of TLD-300 depended on proton energy in the range of 30-100 keV. Conclusion: TLD-200, TLD-300 have sufficient sensitivity to be proton detectors. but they are not a tissue equivalent material and need some calibration process. Furthermore, it still needs more sensitivity calibration factor measurements for different energies of proton to makes proton dose evaluation complete. |
本系統中英文摘要資訊取自各篇刊載內容。