Goniometer Alignment

After you have optimized the beamline, your next step is to make sure that the goniometer is aligned to the x-ray beam. The goniometer alignment procedure requires that a CAT supplied phosphor ball be mounted and optically aligned. It is very important that you align the phosphor correctly – if you do not align the phosphor, then your ability to set the goniometer vertical position correctly will be impossible. You will also need to open the goniometer gui from the main sergui setup file menu. The goniometer gui provides the user with the capability to make small relative moves of the goniometer.

Once the phosphor is aligned you will need to change the camera view to the top camera at a 1x zoom and open the timing shutter. On 22ID, you should set the beamline slits to 20 by 20 micrometers. On both beamlines, you will need to change the attenuation and sample lighting so that you can see a well defined small image on the phosphor ball, as shown below. Now you will need to use the goniometer gui to move the phosphor image onto the red cross hair, which is the goni center of rotation.

The phosphor image in the previous image is off in the horizontal so a small horizontal adjustment is made in the goni gui, resulting in the following image.

You may need to experiment with the goni gui to determine which direction is which in your image display. The goni gui validates the entry so that a user can not make a mistake and try and move the goni a mile or so.

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