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 20 < E < 140 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:

 

XRD-/PDF-/SAXS-CT

Abs-/Phase-Contrast-CT

High Precision Total Scattering

High Frequency Time-Resolved

Energy (keV)

20 – 140

20 – 140

60 – 140

20 – 140

Primary Optics

LLM/DMLM

LLM/DMLM/Pink

LLM/DMLM

LLM/DMLM

Secondary Optics

TF/CRL/KB

-

TF

TF/CRL/KB

Beam size

 

 

 

 

   Vertical (µm)

0.3 – 20

< 6

100 – 200

15 – 200

   Horizontal (µm)

0.3 – 50

< 8

100 – 200

20 – 200

Spatial Resolution

 

 

 

 

   Vertical (µm)

> 0.3 µm

0.6/1.4/3.1

-

 

   Horizontal (µm)

> 0.3 µm

0.6/1.4/3.1

-

 

Detector

Pilatus/Maxipix

Imaging Detectors

Pilatus

Pilatus/Maxipix

Goniometer

HR

HR

HR/HL

HR/HL

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.

 

Pilatus3 X CdTe 2M

Perkin Elmer XRD 1621

Detection technology

Hybrid photon counting

Flat panel

Sensor material

CdTe

CsI

Pixel size [µm2]

172172

200200

Total number of pixels (H V)

14751679

20242024

Maximum frame rate (Hz)

250 (500 with ROI)

15 (30 with 22 binning)

Point Spread Function (FWHM)

1 pixel

2 pixels

Energy threshold (keV)

8 – 40

none

Maximum count rate (ph/s/pixel)

5106

Integrating detector

Non linearity

< 2% at 106 counts/s/pixel

 

Counter depth

20 bit

16 bit

Dynamic range

20 bit

12.8 bit

Minimum exposure (ns)

200

3.3107

Image lag

0

~1% after 100ms

Readout time

0.95 ms

 

File format

CBF, HDF5

Multiframe EDF

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.