Experimental Techniques

• Tender X-ray XAFS
• Hard X-ray XAFS

Overview

This beamline utilizes a double-crystal monochromator to perform XAFS measurements in the tender to hard X-ray energy range. For hard X-ray measurements, in-situ measurements are possible using a sample environment.
Usable gases are limited to harmless gases such as N₂ and CO₂. If users bring their own sample cell and set it up themselves, it will be considered a standard measurement. However, if a sample cell is required, we recommend conducting collaborative experiments with Professor Maiko Nishibori of SRIS, Tohoku University as an advanced measurement. "Coalition Conference's Lecture"(Japanese)
*Please note that the above lecture materials are based on information as of December 5, 2023, and some technical details may have been updated since then.

Additionally, please be aware that advanced measurements may require time for instrument setup and alignment, which is included in the user's allocated beamtime.

Beam Characteristics

Energy

2.1-13keV

Flux

5.6-49x10¹¹ cps (calculated value)

Beam size

Approx. 100 um (estimated value)

Hutch size

Approx. 12.5 m (optical axis direction) x 4 m (width) x 4 m (height)

Light Source and Optics

This beamline utilizes a 5-pole multipole wiggler as its light source and employs a liquid nitrogen-cooled silicon double-crystal monochromator, providing monochromatic X-rays in the tender-to-hard X-ray energy range.
Focusing is achieved with a bent cylindrical mirror, and a double-mirror system for higher harmonic rejection is also installed within the experimental hutch.

Experimental Station

Experimental Equipment

"Tender X-ray XAFS Measurement System" For use below approximately 4 keV
-Total Electron Yield (TEY) and Partial Fluorescence Yield (PFY) can be measured simultaneously (TEY requires the sample to be conductive. Please consider techniques such as metal deposition).
-Measurements are performed under vacuum (He gas not allowed).

"Hard X-ray XAFS Measurement System" For use above approximately 4 keV
-Measurements are performed in air.
-Samples are typically mounted on slide mounts, but the sample geometry is not restricted.

Detector

-For tender X-ray fluorescence measurements: 4-element silicon drift detector (Techno AP Co., Ltd. XSDD50-04GR).
-Various ion chambers for hard X-rays (Applied Photon Technology Co., Ltd.)
-For hard X-ray fluorescence measurements: 4-element silicon drift detector (Techno AP Co., Ltd. XSDD50-04GR)
-Conversion Electron Yield (CEY) detector (Uses He gas; we have one He cylinder for this fiscal year. Obtaining He cylinders has become difficult in recent years. If the He cylinder becomes empty, this method may no longer be available. Additionally, the conversion electron yield method requires the sample to be conductive. Please consider techniques such as metal deposition for insulator materials.)

Layout

XAFS Measurement using transmission method

Figure: Zn XANES spectrum measured by transmission method	Measurement sample: ZnO pellet Measurement element: Zn K-edge Measurement method: transmission method Exposure time: 0.1sec Measurement range: ~k15 Measurement time: about 710sec
Figure: Cu XANES spectrum measured by transmission method(quick scanning)	Measurement sample: Copper foil Measurement element: Cu K-edge Measurement method: transmission method(Quick Scanning) Exposure time: 0.012sec Measurement range: ~k15 Measurement time: about 75sec

XAFS Measurement using Pertial Fluorescence Yield(PFY) method

Figure: Ag XANES spectrum measured by PFY method

Measurement sample: AgO pellet Measurement element: Ag L3-edge Measurement method: PFY method Exposure time: 1sec Measurement range: ~k6 Measurement time: about 850sec

XAFS Measurement using Conversion Electron Yield (CEY)

Figure: Mn XANES spectrum in steel measured by CEY method	Measurement sample: steel Measurement element: Mn K-edge Measurement method: CEY method Exposure time: 1sec Measurement range: ~k6 Measurement time: about 680sec
Figure: Cu XANES spectrum of copper foil measured by CEY method	Measurement sample: copper foil Measurement element: Cu K-edge Measurement method: CEY method Exposure time: 1sec Measurement range: ~k6 Measurement time: about 680sec

Amount of measurement time

Measurement time calculation formula
    (number of pre-edge steps + XANES steps + EXAFS steps(steps*(k-number after XANES)))
       * (exposure time + diffraction crystal moving time(over 1sec, defind by X-ray energy))

Measurement time calculation example
    ·exposure time : 0.1 sec
    ·diffraction crystal moving time : 1.0 sec
    ·wave number : K16
    ·XANES(~K4) steps : 250
    ·other steps : 30

Measurement time = ( 30 + 250 + 30 * ( K16 - K4 )) * ( 0.1 + 1.0) ⇒about 704 sec

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