大型放射光施設 SPring-8

問い合わせ番号

INS-0000000312

ABSTRACT

  BL39XU is an undulator beamline that is dedicated to hard X-ray spectroscopy and diffractometry requiring control of the X-ray polarization state. The major applications of the beamline are X-ray magnetic circular dichroism (XMCD) spectroscopy in 3d transition metals and compounds, rare-earth elements, and 5d metals. The most important feature of BL39XU is the tunability in X-ray polarization states; horizontal/vertical linear, right/left circular, or arbitrary elliptical polarizations are available using diamond X-ray phase plates. The experimental station is equipped with the XMCD spectrometer. Available sample environments are 11 ~ 500 K or 4 ~ 300 K, with the helium-flowing type cryostat or for Pulse-tube type cryostat, and 3.5 T (1.5 T) of magnetic field at room (low) temperature. For further high-field and low-temperature environments, the 7 T superconducting magnet system is ready to use. A helicity-modulation technique at 30 ~ 40 Hz for precise XMCD measurements is routinely used. This technique allows extremely high quality XMCD spectra obtained in a short acquisition time. 
  For microscopic studies, additional KB mirror optics are used to focus a circular polarized X-ray beam into a φ2-10 μm spot.  Using this microbeam, scanning XMCD imaging and element-specific magnetization measurement can be performed. A diamond anvil cell (DAC) is available for XMCD experiments at high pressures (ambient pressure ∼ 180 GPa).
  From 2011A, the nanobeam X-ray absorption spectrometer is available to users at BL39XU, enabling them to perform analyses using 100-nm-order X-ray beams. The spectrometer has been installed by the SR Nano-Beam Analysis Center for Green/Nano-technologies (participating institution: RIKEN), a satellite of the Research Base Networks to Develop a Low-Carbon Society project initiated with a second supplementary budget for fiscal 2009 as part of the Environmental Energy Technology Innovation Plan, which is stationed as a Stepping Stone for Growth Strategy.

AREA OF RESEARCH

• X-ray magnetic circular dichroism (XMCD) spectroscopy
• Element-specific magnetometry (ESM)
• X-ray emission spectroscopy (XES) and its magnetic circular dichroism
• XMCD and XAFS microscopy and local ESM with a 100-300 nm spatial resolution
• XAFS and XMCD at high pressure
• X-ray spectroscopy using variable X-ray polarization

KEYWORDS

• Scientific field
  X-ray magnetic circular dichroism, Element-specific magnetometry, Magnetic EXAFS, Magnetic diffraction, Magnetic scattering, Polarization XAFS, microbeam, magnetic imaging, high pressure
• Equipment
  X-ray phase plate, Diffractometer, Electromagnet, Superconducting magnet, Cryostat, Polarization analysis, KB focusing mirrors, diamond anvil high pressure cell (DAC)

SOURCE AND OPTICS

  This beamline is equipped with an in-vacuum type undulator and a diamond double-crystal monochromator. The combination of fundamental / third harmonics of undulator radiation with the Si 111 or Si 220 reflection of the monochromator enables an energy range of 5 - 37 keV. The photon flux onto a sample is maximized at every X-ray energy by synchronous tuning between the undulator gap and the monochromator angle. A Rh-coated mirror of horizontal deflection is used to reduce the amount of higher harmonics to less than 10^-4. The cutoff energy is adjustable from 8 to 20 keV with an appropriate glancing angle between 2 and 8 mrad. The mirror is mechanically bendable for providing a horizontally focused beam (50 - 100 μm in FWHM).

• Beamline layout
  

  A diamond X-ray phase retarder (XPR) is installed between the monochromator and the mirror. It functions as a quarterwaveplate with high efficiency. Crystals of various thicknesses (0.10, 0.34, 0.45, 0.73, 1.4, 2.7, 4.7, and 6.5 mm) are available; selection of an appropriate crystal allows the use of high rate (> 90%) circular polarization of both helicities at 5 ∼ 23 keV. Vertical linear polarization of a reasonable polarization rate (40 ∼ 90%) is also available with an XPR used under the halfwaveplate condition.

• X-rays at Sample

   

  Energy range	5 ∼ 37 keV (Si 111 or Si 220)
  Resolution ΔE/E	2 × 10-4 (Si 111),  1 × 10-4 (Si 220)
  Flux at sample	5.3 × 1013 photons/s (Si 111),  2.4 × 1013 photons/s (Si 220) @ 10 keV
  Beam size at sample (FWHM)	0.6 (V) × 0.6 (H) mm2
  Higher harmonic content	< 1 × 10-4
  Linear polarization rate	99.9 %
  Circular polarization rate	> 90 %

   

EXPERIMENTAL STATIONS

• X-ray emission spectrometer
• Electromagnet and closed-cycle helium refrigerator
• 7 T superconducting magnet (Temperature: 2 K)
• Helicity-modulation XMCD
• Examples of experimental data
• Facilities and Accessories

PUBLICATION SEARCH

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BL39XU PUBLICATION SEARCH

CONTACT INFORMATION

Please note that each e-mail address is followed by "@spring8.or.jp."

Naomi KAWAMURA
SPring-8 / JASRI
1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198
Phone : +81-(0)791-58-0833
Fax : +81-(0)791-58-0830
e-mail : naochan

Kotaro HIGASHI
SPring-8 / JASRI
1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198
Phone : +81-(0)791-58-0833
Fax : +81-(0)791-58-0830
e-mail : higashi