本研究調查國內現役13部迴旋加速器醫用同位素產製設施的生產紀錄，其運轉以(p,xn)核反應占大宗，尤其是18O(p,n)18F最為常見。為了能夠可靠且全面性地評估臺灣迴旋加速器同位素產製設施的物質活化潛勢，本研究利用FLUKA蒙地卡羅程式深入探討從核反應截面、同位素產率、二次中子的生成與遷移，周遭中子輻射場、以及最後物質活化的物理過程與輻射特性，分析結果並與文獻實驗或計算值比較，驗證本研究所建立模型與參數的合理性。針對前述設施同位素產製所使用的(p,xn)核反應式，本研究考量10組不同靶材及射束能量的假設組態進行模擬分析，並針對照射室內二次中子的能量與空間分布、周圍等效劑量率以及物質活化的結果進行比較。本研究發現並量化確認，當中子產率歸一化後，不同靶材與運轉情節的中子分布、劑量分布與物質活化具有高度的相似性。此一特性有利於不同設施與運轉情節之活化分析的結果互為引用參考，本研究以3種不同的案例示範此一延伸應用，可在合理的誤差範圍內減少不必要的重複模擬計算，有利於相關設施未來除役的準備工作。

This study investigated the production records of 13 cyclotron medical isotope production facilities in Taiwan, and the (p,xn) nuclear reaction are often used in the past, especially 18O(p,n)18F. In order to calculate activation effectively and comprehensively, this study use FLUKA Monte Carlo code to calculate nuclear reaction cross-section, isotope physical yield and secondary neutron yield, neutron spectrum, ambient dose equivalent and the physical process and radiation characteristics of the material activation material activation. The results compared with experimental or calculated values in the literatures verify the acceptable model and parameters applied in this study. 　　For the common (p,xn) nuclear reaction type used in Taiwan, choosing 10 assumed designs of different target and beam energy to calculate and compare the characteristics of neutron spectrum, ambient dose equivalent rate, and material activation in the cyclotron room. After the neutron yield is normalized, the neutron distribution, dose distribution and material activation of different targets and operation scenarios show a high degree of similarity. This feature is beneficial to different facilities and operation scenarios to estimate unknown results of material activation by referring each other. In addition, this study also apply 3 different cases as extended applications to quantify the difference between each (p,xn) reaction channels by the ratio of estimated and FLUKA calculated results. Good matching results can let facilities evaluate the results of other reaction channels within a reasonable range to reduce unnecessary calculations to benefit the preparation of future decommissioning of related facilities.

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