10:15 AM - 10:30 AM
[MTT44-05] Introduction of New X-ray Microscopes for the Analysis of Earth and Planetary Science Samples and Their Actual Application
Keywords:X-ray Micro-spectroscopy, Synchrotron Radiation, STXM, TXM, SFXM, Meteorite
The Scanning Transmission X-ray Microscopy (STXM) has been used widely in analyzing earth and planetary science samples in recent ten years. The full-field Transmission X-ray Microscopy (TXM) and the Scanning Fluorescence X-ray Microscopy (SFXM) are being developed in SPring-8 as complementary X-ray microscopes with a comparable spatial resolution (tens to hundreds of nano-meter) as STXM. Both have unique features that STXM does not have (see Note 1). In this presentation, we will introduce the details of these two X-ray microscopes, including a comparison with STXM, and report the results of preliminary analysis of earth and planetary science samples (meteorites) using these microscopes.
TXM experiments are performed in the C-branch of BL27SU, enabling us to observe samples with a spatial resolution of less than 100 nm in a field of view of 50 x 50 μm in a measurement time of 1 second per image. As with STXM, TXM-XANES can be combined with X-ray absorption near-edge fine structure (XANES) analysis. The advantage of TXM-XANES is that it can analyze chemical states in a wider field of view in a shorter time than STXM. In this study, we have investigated NWA 7312 (ultramafic achondrite) by TXM-XANES and identified the spatial distribution of particulate Fe-bearing phase (e.g., sulfides) in the olivine and Fe-rich rim around the olivine.
The SFXM is installed in the A-branch of BL17SU. It is a scanning X-ray type microscope like the STXM, but it can analyze the trace elements on thousands of ppm and the major elements because it detects the X-ray fluorescence. As for the sample preparation, need to the surface of the sample is smooth, and there is no need for additional processing such as ultra-thin sectioning using an ultramicrotome or focused ion beam (FIB), which is an advantage in the field of earth and planetary sciences, where valuable samples are often used. In the case of trace element measurement, the measurement time is longer than that of STXM because the measurement time per measurement point is set to about 1 s in a step scan mode to obtain sufficient X-ray fluorescence intensity. Although it takes longer than STXM to measure the trace elements, performing sub-micron structural observation and trace element analysis using 200-400 nm focused X-ray with easy sample preparation has a practical use. Here, we introduce a preliminary result of SFXM-XANES of clay mineral and amorphous silica veins in the iddingsite structure of Martian nakhlite Y000593 and the identification of clay minerals and chemical state analysis of amorphous silica.
Note 1: In the soft X-ray region (280 to 3000 eV), SFXM in BL27SU has been used for speciation analysis of trace elements with a spatial resolution of about 10 μm in a decade. In the hard X-ray region (above 4500 eV), TXM and SFXM in BL37XU and other beamlines in SPring-8 have a similar spatial resolution (< 100 nm), which are actively used in a wide range of research fields from earth science and environmental science to next-generation battery materials and magnetic materials.
TXM experiments are performed in the C-branch of BL27SU, enabling us to observe samples with a spatial resolution of less than 100 nm in a field of view of 50 x 50 μm in a measurement time of 1 second per image. As with STXM, TXM-XANES can be combined with X-ray absorption near-edge fine structure (XANES) analysis. The advantage of TXM-XANES is that it can analyze chemical states in a wider field of view in a shorter time than STXM. In this study, we have investigated NWA 7312 (ultramafic achondrite) by TXM-XANES and identified the spatial distribution of particulate Fe-bearing phase (e.g., sulfides) in the olivine and Fe-rich rim around the olivine.
The SFXM is installed in the A-branch of BL17SU. It is a scanning X-ray type microscope like the STXM, but it can analyze the trace elements on thousands of ppm and the major elements because it detects the X-ray fluorescence. As for the sample preparation, need to the surface of the sample is smooth, and there is no need for additional processing such as ultra-thin sectioning using an ultramicrotome or focused ion beam (FIB), which is an advantage in the field of earth and planetary sciences, where valuable samples are often used. In the case of trace element measurement, the measurement time is longer than that of STXM because the measurement time per measurement point is set to about 1 s in a step scan mode to obtain sufficient X-ray fluorescence intensity. Although it takes longer than STXM to measure the trace elements, performing sub-micron structural observation and trace element analysis using 200-400 nm focused X-ray with easy sample preparation has a practical use. Here, we introduce a preliminary result of SFXM-XANES of clay mineral and amorphous silica veins in the iddingsite structure of Martian nakhlite Y000593 and the identification of clay minerals and chemical state analysis of amorphous silica.
Note 1: In the soft X-ray region (280 to 3000 eV), SFXM in BL27SU has been used for speciation analysis of trace elements with a spatial resolution of about 10 μm in a decade. In the hard X-ray region (above 4500 eV), TXM and SFXM in BL37XU and other beamlines in SPring-8 have a similar spatial resolution (< 100 nm), which are actively used in a wide range of research fields from earth science and environmental science to next-generation battery materials and magnetic materials.