OptimiseBeam

What does Quick Realign do?

This quick alignment moves the experiment table to the most intense section of the X-ray beam. The alignment takes a bit less than 2 minutes during which the sample is not exposed. 

For afficionados, the details of the scans performed in spec are below:

1. dscan thgt -2 2 20 0.3 (counter i0_flux, move to center of Gaussian or the highest point) 
2. dscan ttrans -2 2 20 0.3 (counter i0_flux, move to center of Gaussian or the highest point)

What numbers should I expect?

The 'flux_i0' intensity of the beam is shown in mxCuBE on the right. To observe the flux you need to open the 'safety shutter' first. Your crystal will not be exposed during this time. Sometime the flux value is reported as ~1 x e(10) - this is an electronic issue and there is no X-rays. For a ring current of 200 mA, a beamsixe of 100 x 100, an energy of 13.2 and 100% beam you should get values >2-3 x e(12). Some values are shown below for different energies with a ring current of 200 mA, the undulator setting shown, a beam size of 100 x 100 and 100% of the beam. These reference values need to be scaled for different ring currents.