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In order to determine the optimum set up for each experiment, a couple of important pieces of information are needed. If you do not understand or know the answers to any of these questions, please contact a member of the beamline team who will be happy to advise you.

  • What is the q range of interest for your experiment?
  • Which energy will you need to use for your experiment?
  • Does your sample has a preferred orientation or alignment? Do you want to maximise the q-range by setting the beamstop at the top, or investigate orientation effects using a central beamstop?
  • Do you need to measure WAXS?

Using this information, the table below can help you to work out the set up requirements for each experiment. Please note that there is a time cost associated with all set up changes during an experiment and so we do not recommend more than one camera length, energy or sample environment change during an experiment. Please discuss all set up requirements in advance with your local contact.

Energy and wavelength

The beamline team will often refer to the energy of the beamline, which relates to the wavelength of the light used. I22 is monochromatic, so a single wavelength is used. Energy and wavelength are related by this simple equation:

Most laboratory sources and other scattering tools will refer to the wavelength rather than the energy, so it's good to know how to switch between the two. Some popular choices of energy are:

12.4 keV1 Å
8 keV1.54 Å (Cu K alpha)
17.5 keV0.71 Å (Mo K alpha)

Camera length and energy table

SAXS using Pilatus P3-2M (2D detector) 

Isotropic SAXS (Beamstop at top)

Sample-Detector Distance / mEnergy / keVqminqmaxdmindmax



 Anisotropic SAXS (Beamstop at centre)

Sample-Detector Distance / mEnergy / keVqminqmaxdmindmax


WAXS using Pilatus3-2M-DLS-L

The exact q-ranges available from the WAXS detector are variable due to the large number of possible sample/WAXS Detector/SAXS detector configurations but, as a guide, numbers below are given for sample - WAXS detector distance = 175.4mm and with the pirmary beam passing 2mm from the edge of the WAXS detector chips.

Energy (keV)qminqmax (Horizontal)qmax (Vertical)



NOTE: For a given detector geometry and energy, if qmin(WAXS) < qmax(SAXS) you will have overlap between data sets.

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