Development of X-ray photoacoustic spectroscopy and application to biological analysis

开发了x射线光声光谱方法，并进行了基础研究。1) x射线差分光声方法及成像分析。建立了扫描x射线光声成像方法。信号中由于热传导穿过表层而产生的时间滞后被检测为相位滞后，该相位滞后也被成像并用于估算表层深度。这种方法将使我们能够对金属离子进行三维分析。计算机断层扫描（CT）的x射线光声成像也得到了发展。该方法易于应用x射线双波长差成像，明确了样品中特定原子组分的分布。在x射线光声光谱中发现了x射线吸收光谱（EXAFS）的精细结构。该方法无需破坏性取样程序即可揭示表层以下的结构和光学不透明材料。并对粉末的生物样品进行了测定。半脉冲x射线光声光谱的发展半脉冲x射线照射到样品上。结果表明，对来自亚层的信号进行检测和分离，得到表层的深度和/或热性质。这些诺贝尔方法可用于各种材料的无损评价和表征。

X-ray photoacoustic spectroscopic methods were developed and the fundamental studies were perpormed.1) Differential X-ray photoacoustic method and imaging analysis. Scanning X-ray photoacoustic imaging method was developed. The time lag in the signal which is due to the heat ptopagation through the surface layer was detected as phase lag and this phase lag was also imaged and used for the estimation of the depth of the surface layer. This method will enable us a 3-dimensional analysis of metal ions. X-ray photoacoustic imaging by computer tomography (CT) was also developed. Difference imaging using two wavelenfgt of X-ray was easily applied in this method which clarified the distribution of specific atomic components in the sample.2) Development of Photoacoustic EXAFS The fine structure in X-ray absorption spectrum (EXAFS) was found in X-ray photoacoustic spectra. This method revealed the structure below the surface layer and the optically opaque materials with no destructive sampling procedure. The biological samples of powder was also measured.3) Development of Semi-pulse X-ray Photoacoustic spectroscopy Semi-pulse X-ray was irradiated to samples. It was found that the signal from sublayer was detected and separated to get the depth and/or thermal property of surface layer. These nobel methods are useful for non-destructive evaluation and characterization of wide varieties of materials.