ID24 - Energy dispersive X-ray absorption spectroscopy beamline

New beamline complex

Top view of the ID24 complex.

Status

• The original ID24 (pre-upgrade ID24 pages) was closed on 12 July 2010 for a major refurbishment.
• Construction of the new beamline took place between July 2010 and June 2011.
• First beam in the optics hutch achieved in June 2011.
• New optics were commissioned July – September 2011.
• EDXAS_S will be under commissioning until June 2012.
• EDXAS_L will be under commissioning May - September 2012.
• First users expected on EDXAS_S from May 2012.
• First users expected on EDXAS_L from September 2012.

First X-ray beam in the ID24 optics hutch was achieved in June 2011.

Description

Energy Dispersive X-ray Absorption Spectroscopy (EDXAS) is a now a well-established method which has been applied to a broad range of applications (for a recent review see reference [1] and references therein). Details of research at the ESRF can be found on the pre-upgrade ID24 pages.  Improvements in the new ID24 beamline concern optical scheme, stability, detection speed and efficiency in the use of beamtime. The new sample environments are described below for each branch.

EDXAS_S

Includes a laser-heating setup designed to perform in situ high pressure (> 100 GPa) and high temperature (> 3000 K) studies. The double-sided state-of-the-art system is based on two 100 W IR (1064 nm) fiber lasers. Focal beamshapers provide flat-top heated spots, guaranteeing not only stable heating, minimal thermal gradients and negligible diffusion, but also reliable temperature measurements using a high-resolution spectrometer. An additional green (532 nm) laser is used to excite in-situ ruby fluorescence and Raman signal.

EDXAS_L

EDXAS_L will host a novel concept for synchronous XAFS/infrared studies of functional materials on timescales from  seconds to 10’s of nanoseconds. This is based around a Varian 680 IR spectrometer capable of nanosecond time resolved step-scan infrared coupled with a custom optical arrangement. It will provide IR flux into a 1x1 mm focal spot. A “flat top” DRIFTS cell, will for the first time permit additional pumps and probes to be simultaneously incorporated with the IR and the Dispersive EXAFS for:

• Combined IR/XAS/RAMAN
• Combined IR/XAS/UV-vis
• Combined IR/XAS/IR thermography

Applications

Applications will focus on:

•  the investigation of solid and molten matter at extreme conditions of pressure, temperature and magnetic fields using in-situ static and dynamic XAS
•  time resolved studies of homogeneous and heterogeneous chemical reactions, catalysis  and aspects of solid state chemistry

Scientific applications of ID24.

Characteristics

Source: U27/U32 undulators in 6 m high beta straight section
Energy range: 5-27 KeV
Photon Flux on the sample:  0.5 – 2x10¹⁴ photons/second with Si (111) polychromator
Time resolution for single shot acquisition: 1 µs
Energy resolution: within core-hole lifetime broadening
EXAFS k max at 7 keV: 13 A^-1
Spot size:
     EDXAS_S: 3x3 µm FWHM (5-15 KeV)
     EDXAS_L: variable from 20x3 to 200x200 µm FWHM

References

[1] Energy Dispersive Absorption Spectroscopy for Hard X-ray micro-XAS applications, S. Pascarelli, O. Mathon, M. Munoz, T. Mairs and J. Susini, Journal of Synchrotron Radiation 13, 351 (2006).