Materials Chemistry- EH3

The materials chemistry hutch at ID15A is devoted to operando and time resolved diffraction and imaging, total scattering, and diffraction computed tomography. The station is optimised for rapid alternation between the different techniques during a single operando experiment in order to collect complementary data on working systems. The high available energy (up to 120 keV) means that even bulky and highly absorbing systems may be studied. The combination of the beamline's optimised focusing optics and a photon counting CdTe pixel detector allows for both unprecedented data quality at high energy, and for very rapid triggered experiments.

Key points

• Energy range, monochromatic 40 < E < 120 KeV
• Beam sizes from 0.3 µm to 8 mm

Techniques

• Angular dispersive diffraction using area detectors
• Pair distribution function experiments
• X-ray imaging, fast tomography, diffraction tomography

Experimental hutch overview

As shown below, EH3 contains four main elements mounted on highly stable granite platforms. From right to left, these are 1) Secondary focusing using compound refractive lenses; 2) A sample stage containing both heavy and light duty sample towers; 3) A detector stage with long translations; and 4) An ancillary table offering the ability to mount a SAXS detector.

The following experimental configurations are available in standard operation:

X-ray diffraction detectors

EH3 is equipped with a Dectris Pilatus3 X 2M utilising a CdTe sensor. This detector gives unprecedented data quality at high energy, as can be seen in the comparison of its characteristics with respect to a conventional flat panel detector such as the commonly used Perkin Elmer XRD 1621, and in the comparison between data taken in identical conditions with the two detectors.

X-ray imaging detectors

A range of imaging cameras are available for experiments which require complimentary absorption tomography. These detectors are permanently mounted and can be used sequentially with the diffraction and/or SAXS detector and one another. The detectors system characteristics are listed below.

SAXS detector

ID15A is equipped with a single photon counting Maxipix CdTe detector (Ponchut, et al., 2011) for time-resolved high energy SAXS. Measurements over a q-range from 0.01 to 1 nm^-1 are possible at 30 keV, and the CdTe sensor ensures that much higher incident energies can also be used.  The maximum frame rate is 350 Hz, making it particularly well suited for time-resolved experiments and SAXS-CT. In addition to the standard acquisition mode, the detector features, similar to the Pilatus3 detector, there is an electronic gating option with a minimum exposure time of 100 ns. This opens new possibilities for high energy time-resolved SAXS experiments on the sub-microsecond time scale using a stroboscopic approach as already demonstrated with the Pilatus detector. The main detector parameters are listed below.

Ancillary probes

The beamline retains access to all of the equipment held in the sample environment pool. In addition, several dedicated probes are available for simulataneous measure during scattering and/or imaging experiments. A dedicated Bruker Vertex 80 spectrometer, a Hiden QGA mass spectrometer are available for operando experiments. Together with our large stock of mass flow controllers, regulators and fittings, this means that custom experiments for e.g. heterogeneous catalysis may be performed. The IR detector and sample chamber are shownn below mounted on the beamline.

A Hitachi Vortex®-EM silicon drift X-ray fluorescence detector with a special 1mm thick Si crystal for high energies is available. The detector is combined with a fast Mercury/XIA readout electronics allowing exposure times of a few milliseconds. The Vortex detector can be used to perform simultaneous fluorescence mapping and XRD mapping or fluorescence CT and XRD-CT.

Sample environments

A number of sample environments are available to control the sample temperature between about 80 - 1500 K. Lower temperatures are avaliable with equipement from the sample environment pool.

Scientific Techniques

The new beam line makes techniques like diffraction tomography, pair distribution function analysis, and ultra-fast hight energy diffraction routinely accessible to the full ESRF user community. Please see the Scientific Examples page for more information.