Since January 2015 the X-ray beam is focussed by compound refractive lenses. The system in place can vary the beam size from 10 x 5 up to 110 x 100 microns across the available energy range. This is all controllable through the GDA GUI.

Selecting a Beam Size

At a given energy to change beam size select the vertical beamsize you require in the OAV tab controls shown in the red box below. In this case the current microfocus beam size (11 x 5 microns) is shown on the crystal as a red oval.

This will change the optical configuration and perform a simple realignment. Below shows the viewing system with an updated beam size shown by the red oval of 63 x 50 um:

If you have set up a queue of data collections, loading sample after sample, you can change your beam size prior to each data collection so as to match the beam size to your crystals (bearing in mind the time it takes to do this).