Experimental Techniques

• Soft X-ray photoelectron spectroscopy (XPS)
• Soft X-ray absorption fine structure (SX-XAFS)
• Ambient soft X-ray photoelectron spectroscopy (AP-XPS) (Advanced measurement)
• Operando soft X-ray absorption fine structure (operando SX-XAFS) (Advanced measurement)

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Overview

BL08U is a beamline that utilizes soft X-rays in the energy range of 180 to 2000 eV to analyze the electronic states of materials. It is designed to use vertical and horizontal linearly polarized light, as well as left and right circularly polarized light, generated by an APPLE-II type elliptical undulator (please ask us if you wish to use polarization other than horizontal linear polarization). The optical system employed has no energy dependence on the deflection angle or divergence, enabling soft X-ray spectroscopy measurements in a high-energy resolution mode and scanning imaging in a high-flux mode.

As for the experimental station, an Ambient Pressure X-ray Photoelectron Spectroscopy (AP-XPS) system is installed, which allows for the quantitative analysis of the chemical states of solids. The spot size on the sample is 30 µm (height) x 80 µm (width). Standard measurements are performed under ultra-high vacuum (10^-10 mbar), while advanced measurements can be conducted in the pressure range of 100 to 1023 mbar. The sample temperature during measurement can be controlled from room temperature up to 500°C.

Beam Characteristics

Energy Range

180～2000 eV

Flux

> 1x10¹² photons/s　 (calculated value, depends on energy and experimental conditions)

Beam Size

XPS: 30 µm (vertical)    x     80 µm (horizontal)
XAS: 1 mm (vertical)    x     1 mm (horizontal), unfocused

Light Source and Optics

The light source is a 71-pole, 56 mm period APPLE-II type undulator, and monochromatic soft X-ray beams are available via a grating monochromator. The exit slit is located downstream of the monochromator, which can be used to adjust the energy resolution and as a virtual point source in scanning imaging.

Experimental Station

Measurement Methods

XPS:    Approx. 2-3 minutes per spectrum
AP-XPS:    Approx. 15 minutes per spectrum
SX-XAFS (Total Electron Yield, Partial Fluorescence Yield):    Approx.15 minutes per spectrum

Sample dimensions

XAS:    Maximum 14 mm (height)    x    12 mm (width) (thickness: several mm)
XPS:    Maximum 11 mm (height)    x    11 mm (width)

Sample Plates

・XPS　　　　　　　　　　　　　　　　・SX-XAFS(Standard Measurement)
　　
　　　　　　　　　　　　　　　　　　　 Sample Mounting (BL08U SX-XAFS)

Sample Requirements

XPS:
・Electrically conductive solid with the observation target located within 2 nm depth from the surface.

SX-XAFS:
・Total Electron Yield: Electrically conductive solid with the observation target located within 5 nm depth from the surface.
・Partial Fluorescence Yield: Solid with the observation target located within 100 nm depth from the surface; compatible with insulating samples.

Transfer vessel (for standard SX-XAFS measurements)

　　
　　　　　　Transfer vessel　　　　　　　　　　　　　　　　　Sample bank

If you wish to use the transfer vessel, please indicate this in your beamtime request.

Measurement Steps (Standard Measurements)

・XPS

・SX-XAFS

Layout