The CdTe Eiger2 9M detector is a new type of detector that allows routine high energy MX. At high energies the diffracted intensity per unit absorbed dose is increased for protein crystals. This means you can use a lower dose to obtain the same Bragg intensities and so your crystal will last longer in the X-ray beam. Evidence for this can be found in the IUCrJ paper

Experimental evidence for the benefits of higher X-ray energies for macromolecular crystallography

Selina L. S. Storm, Danny Axford and Robin L. Owen

https://doi.org/10.1107/S2052252521008423

For data collections when you don't need to be near an elemental edge for phasing there is really no downside to collecting at 17.5 or 20 keV compared to 12.4 keV. The CdTe E9M detector can also be used at 'standard' MX energies but it is worth reading the below before choosing the best detector for your beamtime.  

Please let us know if you have feedback on the detector or these pages.

The Pilatus you are familiar with is still in place. You can switch between the detectors using GDA

Click the relevant 'change to..' to choose the detector you want to use.

The detectors are mounted in an 'up and under' configuration. it takes ~5mins for the vertical stage to move between detectors.

High energy notes

Our default high energies are currently 17.5 keV (flux approx 3x10^12 ph/s) or 20 keV (flux approx 2x10^12 ph/s). Higher energies will become accessible in the near future. If you have a pressing reason to push higher please talk to your local contact ahead of your beamtime.

'Normal' energy notes

Our default 'normal' energy is 12.4 keV. The CdTe works well at 12.4 keV but note that an Eiger 9M is somewhat smaller than a Pilatus 6M. Currently the minimum crystal to detector distance is 200 mm (we are working to reduce this). At this distance and at 12.4 keV

• Eiger 9M inscribed circle 1.91 Å
• Pilatus 6M inscribed circle 1.27 Å

The data quality from the two detectors at 12.4 keV is comparable. See comparative plots from a selenium soaked thaumatin crystal below. The dominant factor at high resolution is the detector size and the differing fall off in stats reflects the size of the detector. 

You can also collect good data using the CdTe E9M below 12 keV but at some point the area of the detector will become limiting

• Which detector to use? It depends on what you're doing
  • High energy (above approx 17 or 18 keV) - CdTe Eiger
  • Standard energy (~12.4 keV). You choose/talk to local contact. If high resolution data is important you might want to use the pilatus
  • Low energy: Si Pilatus. The CdTe will give good data but due to its physical size/the min detector distance the resolution of data you can collect will be limited.
  • Serial - Fixed targets: Si Pilatus only (for now). Extruder - choice of detector.
• Fluxes
  • At 12.4 keV the flux is approx 8x10^12 ph/s
  • At 20 keV the flux is approx 2x10^12 ph/s  (nb interim flux. Will increase as ID commissioning progresses)
• For information on file formats, handling and image viewing etc see the introduction to Eiger2 detectors.

https://www.diamond.ac.uk/Instruments/Mx/I04/I04-Manual/Eiger2-Detectors.html