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X-ray Absorption Spectroscopy

X-ray absorption spectroscopy (XAS) takes advantage of the continuous emission spectrum of synchrotron radiation, in which the incident photon energy is scanned by using a monochromator and the absorption coefficient of the sample is recorded against the energy. In general, one spectrum can be roughly divided into three regions, namely, pre-edge, near-edge (XANES), and post-edge (EXAFS) regions. The XANES can reflect the electronic properties of the absorbing atom (such as the oxidation state and d-orbital occupancy) and can be utilized to distinguish different site symmetry. On the other hand, the EXAFS provides the information of local atomic structure around the absorbing atom, including the type and the number of atoms in specific coordination shell, the interatomic distance, and the structural disorder. The samples are not required to have a structure of long-range order so that either crystallite or amorphous solid and even liquid or gas all can be measured. If the sample consists of many elements, each individual element can be measured by tuning the photon energy to the absorption edge of the corresponding element. For a biological sample system, X-ray absorption spectroscopy has been widely employed to probe the electronic structure (particularly oxidation state) and atomic structure (formation and breaking of chemical bonding) of the metal center during the course of biochemical reaction.

►Contact Information

If you have any technical concerns, please contact us!

BL17C1 Spokesperson:
Lee, Jyh-Fu (, +886-3-578-0281 Ext: 7117)

BL17C1 Beamline Manager:
Huang, Yu-Jie (, +886-3-578-0281 Ext: 7127)

►Technical Information

Operational (general use)

Yes (since January, 1999)

%Time available (general use)



X-ray Absorption Spectroscopy (XANES and EXAFS)


25 Poles, 20 cm Period Length Wiggler (W20)

Ring Current(mA)

300 mA

Average Beam Lifetime

Infinite Under NSRRC Top-Up Conditions

Energy Range

4.8 ~ 14.2 keV

Energy Resolution

2.2 x 10E(-4)

Spot Size

FWHM: 6 mm (H) x 2 mm (V)


Vertically Collimating Pre-mirror, Fixed-Exit Double Crystal Si(111) Monochromator, Toroidal Focusing Mirror


5 x 10E(10)

Flux Detailed

Total Flux Measured @ 10 keV

Wavelength Min (Å)


Wavelength Max (Å)



Water-Cooled, Fixed-Exit Double Crystal Monochromator

Crystal Type



Rh Coated

Mirror Cutoff

14.2 keV


Gas Ionization Chambers, Lytle Detector, 13-element LEGe Array Detector

Cryo Capability

Down to ~15 K @ Sample with APD Closed-cycle Cyrostat


Contact in Advance


spec® Control Software


Two PCs Running Linux and Windows



►Station Photos

X-ray Absorption Spectroscopy End-station in BL17C1 Hutch 13-element LEGe Array Detector in Working


►Extension Links