軟X光之同調性與小角度散射研究

Abstract

X光小角度散射提供高穿透力與非破壞性方式，探測物質的微結構及微粒大小和型態，配合特定原子的軟X光共振吸收附近之能量，可分辨共振的原子在整體中的貢獻。藉由軟X光小角度散射技術，我們固定入射角在0.75°和0.5°，改變不同能量，在Q值為0.028 Å^(-1)的地方，看到能量越接近Mn的吸收峰時，散射強度越強，並從大Q值的斜率，推測Mn,Cd-metallothionein-2為橢圓狀。 以往探測光與物質交互作用後的散射光，只能得知其強度，而無法得知重要的相位資訊，使用具有同調性的光源，能夠得到喪失的相位資訊，更了解物質完整的面貌。產生具同調性的光源，可藉由單光器和針孔的幫助，但同時會犧牲光源強度，我們利用國家同步輻射中心所提供之高強度、低散度的光源，建造一座簡單的同調光實驗之實驗站，將光源通過直徑5μm的針孔，看到隨能量而變化的圓孔繞射圖騰，與圓孔繞射理論計算之結果比較，誤差小於20%。

Small angle X-ray scattering provides high penetration and non-destructive way to detect the microstructure, particle size and particle shape of material. With the X-ray absorption energy of a particular atom, we can distinguish the contribution from different elements. With the small angle soft X-ray scattering technique, we fixed incident angle at 0.75 ° and 0.5 °, and changed different photon energies. We found that near the Mn absorption energy, the scattering intensity is high for the Q value being 0.028 Å^(-1). With the slope of the large Q region, we suggest that the shape of Mn, Cd-metallothionein-2 is elliptical. In the past, we only can get the amplitude of scattered light from the interaction of light and matter. However we cannot get the more important information–phase. With a coherent light source, we can retrieve the phase information. Discover the complete picture of material. Using a monochromator and a pinhole, we generated a coherent light source and set up a simple experimental end station for coherent scattering. The coherent light source of high intensity and low divergence. We observed a diffraction pattern from a circular aperture, and the diffraction fringes changed with different photon energies. In comparison with the theoretic calculations, the experimental result has an error less than 20%.