BL04B2 Small angle X-ray scattering diffractometer
問い合わせ番号
INS-0000000307
Small angle X-ray scattering for supercritical fluids
Small angle X-ray scattering experiments are carried out using 37.8 keV X-rays monochromatized by the flat surface of Si (111) crystal as an incident beam. The scattered X-rays are detected with an imaging plate of 300 mm × 300 mm located about 3 m apart from the sample position. A vacuum path is mounted between the sample and the Imaging Plate. Using a lead beam stop, 5 mm in square, the observable wavenumber k (k = 4πsinθ/λ ; λ : wavelength) is estimated to be 0.02 Å-1 to 0.9 Å-1.
- Table 1. The specifications of the high-pressure vessel
Temperature up to 1700°C Pressure up to 200 MPa (more precisely, 196 MPa) Wavenumber 0.02 ∼ 0.9 Å-1 (without the high-pressure vessel)
0.06 ∼ 0.4 Å-1 (with the high-pressure vessel)
Fig.1. The schematic diagram of the spectrometer
Fig.2. The photogragh of the spectrometer
High pressure gas apparatus that permit experiments up to 1700°C and 200 MPa are installed in the experimental hutch. A synthetic diamond 3 mm in diameter of the highest quality is used as a window for the incident beam, and a diamond window 6 mm in diameter is used for scattered X-rays to cover larger k. A cell made of sapphire is used for fluid sample such as selenium and mercury because it is transparent to X-rays and resistant to chemical corrosion by the sample at high temperature.
- Fig. 3. A side view of the high-pressure vessel for the small angle X-ray scattering measurements
- Fig. 4. Small angle X-ray scattering intensity spectra of an empty cell (black line) at 25°C, and the cell and fluid Hg at 1500°C and 1820 bar near the critical density (red line) after absorption correction.
References
- K. Tamura and A. Inui, J. Phys. :Condensed Matter, 13 (2001) R337.