Abstract
本文係探討銩活化氟化鈣( CaF2:Tm，TLD-300 )對質子的回應。質子的來 源由凡氏加速器產生，其能量範圍在 0.7至 3.0 MeV之間。使用兩種不同 回火處理( 經 830 ℃ 回火 90 分鐘與未經此高溫處理 )的銩活化氟化鈣 ，以質子照射，發現輝光峰所處溫度與質子能量有關。質子照射的輝光峰 主要有３個，但經高溫處理者計讀的輝光峰主要有２個。以輝光峰高度比 值和熱發光效率評估質子能量，且使用起始上升方法與分析輝光曲線形狀 的方法進行熱發光參數分析，其結果如下 1.由輝光曲線可看到主要輝光 峰的相對高度有所不同，可鑑別在單一射源的情況下，受質子或加馬射線 的影響。 2.輝光峰比值與熱發光效率隨著入射質子能量變化而有不同， 可由此決定質子能量，但須先做校正曲線。 3.對 Co(60) 加馬射線的曝 露，使用分析輝光曲線形狀的方法而得，第三輝光峰的動力學次數為 1、 活化能為 1.09 eV ，而第五輝光峰的動力學次數為 2、活化能為 1.86 eV 。以起始上升方法分析經質子照射後的三個主要輝光峰的活化能分別 為 E2 =1.95 eV，E3 =2.38 eV， E5 =2.72 eV ；分析輝光曲線形狀的方 法僅能分析第五輝光峰，其動力學次數為 2、活化能為 1.78 eV。 This investigation was to study the response of thermoluminescent material CaF2:Tm phosphor (TLD-300) to protons. The sourse of proton beam was produced by a Van de Graaff accelerator with an energy range between 0.7 to 3.0 MeV. There are two kinds of anneal- ing procedures for TLD-300: one is 830 ℃ or 90 min, the other 400 ℃ for 90 min. There are two glow peaks for the high temperature treatment and three for the low temperature treatment. The peaks' positions ( Tm ) of the glow curve depend on proton energy. The proton energy was investigated by studying the peak height ratio (Hi/Hf) of the glow curve, and the thermolum- inescent efficiency (Hi/TL) of the glow-peak as well. The thermoluminescent parameters of the glow peaks for CaF2:Tm dosimeters were analyzed experimentally by using initial rise and glow curve shape analysis (GCS) methods. The following are the results: 1. The glow-curve distribution can be distinguished between proton and gamma radiation. 2. The proton energy can be determined by the calibration curves of the Hi/Hf or Hi/TL. 3. The activation energies of Co(60) gamma-ray irradiated TLD-300 were 1.09 and 1.86 eV. The kinetic orders were 1 and 2 for the third and fifth peak respectively, which were determined by the GCS method. When the GCS method was applied in the proton- irradiated TLD-300, the fifth peak only could be determined with an activation energy of 1.78 eV and kinetic order of 2. The use of initial rise method for the determination of activation energies for the three main peaks, one can obtain the three energies as 1.95, 2.38 and 2.75 eV.