利用X光光子相關光譜探測動態平衡系統之鬆弛時間與利用三光複繞射方法進行銻化銦晶體之相位研究

Using X-Ray Photon Correlation Spectroscopy to Measure Lifetime in Dynamical Equalibrium System and Study of Phase Relations of InSb Using X-Ray Three-Wave Diffraction

李坤原(Kun-Yuan Lee)

指導教授 ： 張石麟

國立清華大學/理學院/物理學系/碩士(2017年)

摘要

本論文分為兩個部分。第一部分為利用X光光子相關光譜探測動態平衡系統內的鬆弛時間，量測粒子的散射光與其位置有關，動態系統中粒子位置隨時不斷改變所反映的散射強度如同雜訊一般，利用強度的自相關函數可將其動態訊息給推導出來。鈷攙雜二氧化鈰奈米粒子晶體有著受到光照與加熱使氧缺陷生成與消滅的雙向動態變化機制，將此材料特性與XPCS實驗做結合，在樣品同時受到雙向變化且達到動態平衡的狀態下，量測散射強度並利用自相關函數的計算將兩個不同變化方向各自的鬆弛時間所計算出來，除此之外，利用超高解析度單光儀的架設探討時間同調性實驗的可行性。由於樣品的選擇與實驗架設上不甚理想，此次實驗並無法得到預期結果，最後經由理論計算的模擬下，證明在合適的樣品與實驗站的選擇下，可成功解析出樣品雙向動態變化各自的鬆弛時間。第二部分為利用三光複繞射方法進行鍗化銦晶體之相位研究，在一般二光繞射實驗中，由於相位問題無法從中得到晶體各原子面的相位，根據S.L. Chang教授1982年所提的三光複繞射方法，利用多組不因原點選擇而改變的三光不變相位搭配M.T.Tang博士於1988年所推導三光複繞射峰形與相位的關係結果，計算銻化銦晶體各原子面的相位。而峰形擬合方面，此次多考慮了光源水平方向發散角與繞射強度的摺積，使其更符合實驗的實驗情況，使得擬合結果更符合實驗峰形，得到相當精確的結果。

關鍵字

三光繞射 ； 相位 ； 同調散射 ； 鬆弛時間

並列摘要

This thesis includes two sections. In the first section, we apply x-ray photon correlation spectroscopy(XPCS) to measure the lifetime in a dynamical equilibrium system. The scattered intensity from particles which float in the air or suspend in the liquid depends on the positions of which. In dynamical system, the scattered intensity fluctuates with time because the positions of the particles are changing constantly. By using the autocorrelation function, we can obtain the dynamic and the structure information of particles by analyzing the fluctuating intensity. In our study, there are two dynamical mechanisms that Co-doped CeO2 nano-particles are heated and illuminated by X-ray. When the system is in dynamical equilibrium, we measure the scattered intensity from the sample and drive the lifetime using the autocorrelation function. The second section is about using the multi-diffraction method to resolve the phase problem in x-ray diffraction experiment. The multi-diffraction method has been reported by Prof. Chang in 1982. In 1988, Dr. Tang proposed that the invariant phase can be determinated by analyzing he intensity profile of the multi-wave diffraction. We adopted two methods above to study the phase relationships of the structure factors of crystalline InSb. The divergence of the light source in the horizontal direction is also considered in the theoretical analysis to improve the fitting accuracy.

並列關鍵字

three-wave diffraction ； phase ； coherent scattering ； lifetime ； XPCS

參考文獻

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