10:45 AM - 11:05 AM
[BCG06-05] Introduction of Scanning Soft X-ray Fluorescence Microscopes and Some Examples of Applied Observations --- Aiming for Spectromicroscopes which Contribute to the Development of Earth and Planetary Science ---
★Invited Papers
Keywords:Soft x-ray microscope, Elemental mapping, Chemical state analysis
To visualize the distributions of elements that make up the substances, the chemical state analyses of the constituent elements and also the chemical reactions which take place on the surface and/or interface of substances and composite materials under low-vacuum conditions or atmospheric pressure of He gas atmosphere, we have been developing a scanning soft x-ray fluorescence microscope at the soft x-ray beamline BL17SU at SPring-8 since 2017 [1]. After repeated improvements, the microscope has been used for spectroscopic analysis of local areas of various materials since it started working stably in FY2019, and has been open to the public users through SPring-8 Research Proposals since the latter half of FY2022.
By combining a soft x-ray beam focused by an optical element called a Fresnel zone plate (FZP) and a group of high-precision stages, electronic state mapping by two-dimensional microspectroscopy and detailed chemical state analyses of small areas on the sample surface and at the interface of composite materials are realized. With the setup as of February 2023, a focused beam of about 300 to 500 nmPhi was available in the energy ranges of 410 to 756 eV for first-order diffraction and 1230 to 2250 eV for third-order diffraction, but there were energy regions (below 410 eV and 756 - 1230 eV) that were not available. To solve this problem, a new FZP will be added in March 2023, which will cover new energy ranges of 250 to 476 eV for first-order diffraction and 750 to 1428 eV for third-order diffraction. This will enable us to carry out spectroscopic studies using K-shells of light elements such as C/N/O/F, Na/Mg/Al/Si, and L-shells of 3d transition metals. The environment around the sample to be observed can be under conditions of low-vacuum (about 10 Pa) to atmospheric pressure of He gas atmosphere.
The apparatus is connected to the beamline through a differentially pumped chamber using two apertures. The FZP chamber (about 10-4 Pa) and the sample environment (about 10 Pa or He atmospheric pressure) are separated by a silicon carbide window (2 mm x 2 mm, thickness 200 nm), allowing for diversification of the environment around the sample. The soft x-ray synchrotron radiation focused by the FZP passes through the silicon carbide window and is irradiated onto the sample mounted on the high-precision stage after selection of diffraction orders by an OSA (Order Sorting Aperture). The fluorescent soft x-rays from the sample induced by the focused soft x-ray beam are measured using a silicon drift detector, and various spectroscopic measurements such as elemental distribution mapping and x-ray absorption spectrum in local area of sample are carried out.
RIKEN staff members have been conducting research since 2020 to visualize the distribution of elements in diatom frustule, which is also used as an environmental indicators [2], to observe the adhesive bonding interface between thermoplastic resin (PEEK) or carbon fiber reinforced plastic (CFRP) and thermosetting epoxy adhesive [3,4], and also to observe the cross section/interface of a building structure, e.g. a ceramic-tile/adhesive/mortar-structured composite materials [5]. Recently, while applied research in the field of forensic science is being promoted, it is also beginning to be used for research related to earth and planetary science as a public use by general users.
On the day of the conference, details of the apparatus and some examples of applied observations will be presented. The current status of developments of new spectromicroscopes enabling more efficient observations will also be introduced.
References
[1] M.Oura et al., J. Synchrotron Rad. 27, 664-674 (2020).
[2] T.Ishihara et al., PLoS ONE 15, e0243874 (2020).
[3] H.Yamane et al., Commun. Mater. 2, 63 (2021).
[4] H.Yamane et al., Sci. Rep. 12, 16332 (2022).
[5] M.Oura et al., J. Adh. Sci. Tech. (doi: 10.1080/01694243.2022.2093076)
By combining a soft x-ray beam focused by an optical element called a Fresnel zone plate (FZP) and a group of high-precision stages, electronic state mapping by two-dimensional microspectroscopy and detailed chemical state analyses of small areas on the sample surface and at the interface of composite materials are realized. With the setup as of February 2023, a focused beam of about 300 to 500 nmPhi was available in the energy ranges of 410 to 756 eV for first-order diffraction and 1230 to 2250 eV for third-order diffraction, but there were energy regions (below 410 eV and 756 - 1230 eV) that were not available. To solve this problem, a new FZP will be added in March 2023, which will cover new energy ranges of 250 to 476 eV for first-order diffraction and 750 to 1428 eV for third-order diffraction. This will enable us to carry out spectroscopic studies using K-shells of light elements such as C/N/O/F, Na/Mg/Al/Si, and L-shells of 3d transition metals. The environment around the sample to be observed can be under conditions of low-vacuum (about 10 Pa) to atmospheric pressure of He gas atmosphere.
The apparatus is connected to the beamline through a differentially pumped chamber using two apertures. The FZP chamber (about 10-4 Pa) and the sample environment (about 10 Pa or He atmospheric pressure) are separated by a silicon carbide window (2 mm x 2 mm, thickness 200 nm), allowing for diversification of the environment around the sample. The soft x-ray synchrotron radiation focused by the FZP passes through the silicon carbide window and is irradiated onto the sample mounted on the high-precision stage after selection of diffraction orders by an OSA (Order Sorting Aperture). The fluorescent soft x-rays from the sample induced by the focused soft x-ray beam are measured using a silicon drift detector, and various spectroscopic measurements such as elemental distribution mapping and x-ray absorption spectrum in local area of sample are carried out.
RIKEN staff members have been conducting research since 2020 to visualize the distribution of elements in diatom frustule, which is also used as an environmental indicators [2], to observe the adhesive bonding interface between thermoplastic resin (PEEK) or carbon fiber reinforced plastic (CFRP) and thermosetting epoxy adhesive [3,4], and also to observe the cross section/interface of a building structure, e.g. a ceramic-tile/adhesive/mortar-structured composite materials [5]. Recently, while applied research in the field of forensic science is being promoted, it is also beginning to be used for research related to earth and planetary science as a public use by general users.
On the day of the conference, details of the apparatus and some examples of applied observations will be presented. The current status of developments of new spectromicroscopes enabling more efficient observations will also be introduced.
References
[1] M.Oura et al., J. Synchrotron Rad. 27, 664-674 (2020).
[2] T.Ishihara et al., PLoS ONE 15, e0243874 (2020).
[3] H.Yamane et al., Commun. Mater. 2, 63 (2021).
[4] H.Yamane et al., Sci. Rep. 12, 16332 (2022).
[5] M.Oura et al., J. Adh. Sci. Tech. (doi: 10.1080/01694243.2022.2093076)