Beamline Layout and Specification

BL8 Optical Layout

Fig. 1 Simplified schematic of BL8 from source to sample.

Fig. 2 Schematic view of the upgraded BL8 beamline illustrating photon absorbers (ABS), pneumatic valves (PV), low conductance duct (LCD), vertical slit (V-slit), horizontal slit (H-slit), X-ray beam position monitors (XBPM), fluorescent screens (FS), white beam shutter (WBS), double crystal monochromator (DCM), monobeam shutter (MBS).

Specification

The CM system mainly consists of a rhodium-coated, single-crystal silicon flat mirror (Thales-SESO, France), a motorized bender (TOYAMA Co. LTD, Japan), five motorized stages (Oriental motor USA Corp., USA), a UHV chamber (SLRI, Thailand), and supporting granite. The size of mirror, 600 mm (length) × 50 mm (width) × 40 mm (height), is designed at an incident angle of 5 mrad for accepting most photons of 1 – 13 keV.

Table 1 Technical Specifications of XAS

X-ray source, optics, and upgraded specification of the beamline.

Technique	X-ray absorption spectroscopy (XANES and EXAFS)
Energy range	1 keV to 13 keV
Photon flux	Maximum flux about 3 × 10¹¹ phs/s/100 mA is currently available for the Si, P, S, and Cl K-edges. The lowest photon flux is 4 × 10⁷ phs/s/100 mA at the Pb L₃-edge.
Beam size at sample	Defocused (standard): 13 mm (h) × 1.5 mm (v) Focused down to 1 × 1 mm
X-ray source	1.44 T Bending Magnet
Electron beam energy	1.2 GeV
Electron beam current	150 mA – 80 mA
Collimating mirror	Bendable, Rh-coated, single crystal silicon mirror
Monochromator	Fixed-exit double crystal monochromator

Table 2 Technical Specifications of XFI

Technique	X-ray Fluorescence Imaging
Energy excitation	10 keV
Photon flux	10⁹ phs/s/100 mA
Detector	pnCCD with polycapillary optics
Image size at sample	12.3 mm × 12.3 mm, 256 × 256 pixels
Spatial resolution	~68 µm
Detection limit	3.9 wt% (K) → 0.2 wt% (Zn)
X-ray source	1.44 T Bending Magnet
Electron beam energy	1.2 GeV
Electron beam current	150 mA – 80 mA
Collimating mirror	Bendable, Rh-coated, single crystal silicon mirror
Monochromator	Fixed-exit double crystal monochromator

Monochromator Crystals

Crystal type	2d spacing (Å)	Photon energy range (eV)	Measurable element
Beryl(10-10)	7.98	1250 – 4780	Mg
KTP(011)	10.955	1250 – 4780	Al
InSb(111)	7.481	1830 – 7000	Si to Cl (K-edge) Rb to Cd (L₃-edge)
Si(111)	6.271	2180 – 8350	K (K-edge) In to Sb (L₃-edge)
Ge(220)	4.001	3440 – 13000	Energy higher than 3.7 keV

Fig. 3 Photon flux at sample in the 1–13 keV region from the DCM crystals — Fig. 3 Photon flux at sample in the 1 – 13 keV region obtained from the DCM crystals: Beryl(10-10) shown by circles; KTP(011), triangles; InSb(111), diamonds; and Ge(220), squares. The opened and closed symbols indicate the photon flux measured before and after the beamline upgrade, respectively.