為了增加THOR-BNCT設施的品保以及品管措施涵蓋範圍，本研究利用一新型整合式活化偵檢器（整合緩速中子的壓克力假體與七片活化箔片）並建立相關方法論，用以協助確定此設施硼中子捕獲治療中子射束的品質。該能譜確認裝置具有以下特性：只需三十分鐘的射束照射時間即可完成全部箔片的活化；全部實驗流程可在只使用一台高純度鍺偵檢器的狀況下，於一天之內完成。另外，藉由蒙地卡羅程式重新定義之個別箔片響應函數，接續的能譜反解工作可以非傳統方式進行，且依然取得可靠結果。本研究於2020年六月至2021年七月以九次實驗測試確認了此裝置的再現性及性能，並以理論模擬測試建立一個箔片反應率與中子能群變化關係的對照表。使用者可參考此表上的關係，立即從實驗結果判斷THOR-BNCT設施的中子能譜是否發生改變。總體而言，此項裝置可快速偵測中子能譜是否產生變化並量化改變幅度，可用於確認照射條件是否符合設施原本設計。因此，本論文建議可將此裝置作為每月或是每季的品保以及品管措施，以更加提升目前THOR-BNCT設施的品質管理。

To extend the domain of subjects examined in current QA/QC measures in THOR-BNCT facility, this study constructed a methodology based on an integrated activation device integrating PMMA phantom and 7 foils aiming to assure the BNCT beam quality. It requires only 30 minutes beam time and all the process of which can be finished within a day using single HPGe. Additionally, spectrum unfolding can be achieved in an unorthodox yet reliable way using redefined foil response functions calculated by MCNP. From June, 2020 to July, 2021, there are 9 experimental tests conducted which verify the reproducibility and performance of this device. There are also theoretical tests based on simulation that construct a lookup table relating the foil reaction rate and flux variation of neutron groups. Through this table, users can immediately judge whether the neutron spectrum have varied or not on the basis of experiment result. Generally speaking, this device can provide a quick detection on the variation of neutron spectrum and quantify its amplitude. It is suitable for checking if the irradiation condition satisfies the facility's design. Therefore, the incorporation of this detector as a spectrum QA/QC measure in THOR-BNCT on a quarterly or monthly basis is recommended to better the current quality management in THOR-BNCT facility.

Abstract (Chinese) i
Abstract (English) ii
Acknowledgement iii
Contents iv
Table Index vii
Figure Index viii
1 Introduction 1
1.1 Boron Neutron Capture Therapy . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Literature Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.1 Foil Activation Detectors and Neutron Spectrum Measurements . . 2
1.2.2 Characterization Researches on THOR-BNCT Epithermal Neutron
Beam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Scope and Structure of the Study . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3.1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3.2 Structure of this Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Neutron Detection by Activation 6
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Foil Activation Detectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.1 Cross Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.2 Geometry and Purity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.3 Activation Product . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Reaction Rate per Atom of Foil Activation . . . . . . . . . . . . . . . . . . . . . 8
2.4 Germanium Detector for Gamma Counting . . . . . . . . . . . . . . . . . . . . 10
2.4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.4.2 DSPEC and GammaVision . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4.3 Energy and Efficiency Calibration . . . . . . . . . . . . . . . . . . . . . 12
3 THOR-BNCT Facility and Employed QA/QC Measures 17
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.2 On-Line Neutron Monitoring System . . . . . . . . . . . . . . . . . . . . . . . 17
3.3 Established Quality Assurance and Quality Control Measures . . . . . . . . 19
3.3.1 Paired Ionization Chambers . . . . . . . . . . . . . . . . . . . . . . . . 20
3.3.2 Au/Cu Foil Activation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4 Neutron Spectrum Measurement 23
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2 Detectors for Neutron Spectrum Measurement . . . . . . . . . . . . . . . . . 24
4.2.1 Bonner Sphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.2.2 Bare Foil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.2.3 Spherical Activation Detector . . . . . . . . . . . . . . . . . . . . . . . 25
4.3 Maximum Entropy Deconvolution Algorithm . . . . . . . . . . . . . . . . . . . 26
4.3.1 Entropy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.3.2 Optimization and Simulated Annealing . . . . . . . . . . . . . . . . . 27
4.3.3 Scaling Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5 Integrated Activation Device for Neutron Spectrum Unfolding and Spectrum Confirmation at THOR-BNCT 30
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.2 Device Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.3 Response Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.4 THOR-BNCT Neutron Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5.5 Experimental Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5.6 Results and Discussion on Decay Gamma Measurement and Foil Reaction
Rate per Atom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
5.7 Results and Discussion on Spectrum Unfolding . . . . . . . . . . . . . . . . . 89
5.7.1 Choosing Proper Parameter . . . . . . . . . . . . . . . . . . . . . . . . . 89
5.7.2 Initial Spectrum vs. Unfolded Spectrum . . . . . . . . . . . . . . . . . 89
5.8 Sensitivity Test on Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
5.8.1 Changing Proportions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
5.8.2 Tilting Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
5.8.3 Results of Sensitivity Test . . . . . . . . . . . . . . . . . . . . . . . . . . 109
6 Conclusion and Future Work 110
6.1 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
6.2 Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
A Lookup Table for Inspecting Spectrum Change Through Foil Activation
Results 113
B MAXED Practice on MATLAB 116
C Unfolding with Tilted Spectrum as Initial Guess 123
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