FUNDAMENTAL-ASPECTS OF X-RAY PHOTOACOUSTIC PHENOMENA

The mechanism why extended X-ray absorption fine structure (EXAFS) is observed in X-ray photoacoustic spectra, has been discussed from various points of view, however, it is still unclear. We continued to gather many aspects of data of X-ray photoacoustic phenomena in order to solve this question. Recently, we found EXAFS also in phase spectra of X-ray photoacoustic signal and related it with the signal shape. This phenomenon reflects the thermal depth depending on the absorption coefficients, however, there are left still unresolved aspects. All aspects of the data are shown and discussed in relation to its mechanism.