BM23 - XAS Beamline

Synopsis

The main mission of BM23 at the ESRF-EBS is to provide the user community with high-quality EXAFS data in a wide energy domain (4-90 keV unfocused operation and 5-45 keV in focused beam operation), with a high signal to noise ratio over a large k-range. BM23 provides a very large operational energy range with reasonable X-ray flux, high energy resolution: typically a factor 3 to 5 better than the intrinsic spectral broadening at any K or L absorption edge, high spectral signal to noise ratio: above 7.0 * 10ˆ4 for well prepared samples, high beam stability: compatible with the demands of extreme sample environments such as pressure cells, where beam dimensions a few micron are required and a a high level of automation.

Disciplines

• Physics
• Chemistry
• Materials and Engineering
• Environmental Sciences
• Earth and Planetary Sciences

Applications

• Chemistry
• Catalysis
• Electro chemistry
• Solid state physics
• Materials science
• Biophysics
• Environmental science
• Earth and planetary science
• Cultural heritage

Techniques

• XAFS - X-ray absorption fine structure
• XANES - X-ray absorption near-edge structure
• EXAFS - extended X-ray absorption fine structure
• XRF - X-ray fluorescence
• Microbeam
• MicroXANES - micro X-ray absorption near-edge structure
• MicroXRF - micro X-ray fluorescence
• XRD - X-ray diffraction

Sample environments

• CHEMISTRY
• In situ operando XAS/DRIFTS/MS and XAS/XRD/MS
• Gas delivery system and remotely controlled gas mixing setup for reactive gases
• High-pressure chemistry setup (10 bars, 800 K)
• Chemical reactors and furnaces for in situ studies under controlled temperature, pressure and gas feed (for pellets and powdered samples)
• Mass-spectrometer for gas composition analysis
• UV-Vis spectrometer with fiber optics for transmission measurements
• MATERIAL SCIENCES
• Multi-sample holder (16 pellets of 5 mm diameter) under controlled atmosphere
• Liquid He cryostat (4-300K) - pellets
• MICRO-XRF
• Online microscope setup in backscattering geometry for microXRF measurements on large samples
• EXTREME CONDITIONS MICRO-XAS/XRF/XRD
• Diamond anvil cell (DAC) (up to multi-Mbar pressures 400 GPa)
• Resistive heated DAC (1500 K, 100 GPa)
• High-pressure cryostat (5 K, 100 GPa)
• Paris Edinburgh Press

Detectors

• TRANSMISSION XAS
• HV Ionization chambers
• Photodiodes and Avalanche Photodiodes (APD)
• Multi element Silicon Drift diodes
• XRF MEASURMENTS
• Single element Si SDD XRF detector (1mm or 2 mm sensor thickness Parker, Keteck)
• combinable with a polycapillary for microXRF measurements in the DAC
• Multi element Si SDD XRF detectors
• Single element Ge SDD XRF detector (1mm sensor thickness, shared with ID15a)
• ELECTRONICS: FalconX electronics (offering a high saturation level at 1 million counts)
• XRD
• Pilatus 1M detector
• FTIR and Mass spectrometer
• Mass spectrometer: Pfeiffer OmniStar GSD 350
• FTIR spectrometer: Agilent Cary 680 with DRIFTS setup for combined DRIFTS/XAS measurements
• RAMAN
• A PRL system  for online pressure determination in the DAC

Technical details

Time resolution

• 1s for a single EXAFS scan (ΔE = 1 keV,continuous mode)
• 2 s for consecutive EXAFS scans (ΔE = 1 keV, continuous mode)
• fast XRF mapping (continuous mode)

Energy Resolution 

• Si(311) double crystal monochromator (ΔE/E = 2.8 x 10^-5)
• Si(111) double crystal monochromator (ΔE/E = 1.1 x 10^-4)

Energy Stability during energy scans (2 keV)

• 0.002 eV

X-ray beam position stability during energy scans (2 keV)

• 1 micron

REFERENCE PUBLICATION(s)

General publication:

O. Mathon et al., A. Beteva, J. Borrel, D. Bugnazet, S. Gatla, R. Hino, I. Kantor, T. Mairs, M. Munoz, S. Pasternak, F. Perrin, S. Pascarelli, J. Synchrot. Radiat. 2015, 22, 1548.

For extreme condition setups:

A.D. Rosa, G. Garbarino, J.E. Rodrigues, E. Mijit, ..., K.A. Lomachenko, O Mathon (2024) New opportunities for high pressure X-ray absorption spectroscopy at ID24-DCM and BM23 with the Extremely Brilliant Source of the ESRF High Pressure Research 44 (3), 248-276 https://doi.org/10.1080/08957959.2024.2364281