Making a file with X-Y corrections for polar rotation based on 1 optimized point
Recently this kind of X-Y corrections was integrated directly in the MultiAx software, but you can still use this manual procedure if you have troubles.
Axis of the polar rotation is generally not passing through the sample surface. Because of this during the rotation the sample will move away from the focus of the analyzer (and the beam). This can strongly affect polar maps measured in large angular range, especially for small samples.
A way to cope with this problem is to adjust the sample's X/Y position for each new polar angle. To find the correct X,Y for each angle you can first optimize sample position manually for a set of polar angles inside the range of interest and then use them as a reference with interpolation in between (see ).
Theoretically it is possible to do good manual optimization only for one point (in the middle of region of interest) and calculate all other X/Y positions based on this point and the position of polar rotation axis.
To do that find the following icon on the desktop:
You can also find the file . This will create polar corrections for +-40 degrees from the point with good optimization and with step of 2 degrees. Press "Save".
Finally in MultiAx Polar corrections tab press Load File button and select the file "XY-correction" (it should be on top if files are sorted by date).
Manual adjustment is best for small or non-uniform samples where precision is important
Automatic adjustment will work best for middle-sized to big uniform samples.
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There are two special positions stored in the "Positions" tab: TransferPrep and TransferAn, these are standard positions in Preparation and Analysis chambers, respectively. Automatic movement of manipulator between these two positions is considered safe.
To move from Preparation to Analysis chamber first move to TransferPrep, then after all axis have moved, move to TransferAn position. And vice-versa for opposite direction.
Before moving from Preparation to Analysis chamber first make sure that there are no obstacles in the Preparation chamber (heater, quartz microbalance etc are retracted) and open the valve between the chambers.
Even though it is safe, manipulator should not be left unattended while it's moving!
If you put your own equipment, avoid loosely hanging cables.
Movement is safe unless the calibration of manipulator is correct. If you had to use the big red emergency stop button or for any other reason you suspect that coordinates may be wrong, contact the beamline scientist.
If this happens, first thing to do is to press the emergency stop red button. It will cut the power from motors.
Then call the beamline scientist to help. Solution of this problem is currently not available for users.
How to change the reference positions of 6 manipulator axes
In case of problems with communication between the MultiAx program and the manipulator it can happen that calibration of the axes is not correct anymore. It may happen, for example, if you see that coordinate values in the MultiAx window are changing while motors are not actually moving.
To recalibrate one axis go to Settings tab and type in the password (provided by the beamline scientist), then press the Unlock button.
Select the axis and press begin calibration. Set the actual position as determined from the rulers on the motors or visually from the camera image.
Move x and y to 4 mm on the rulers --> recalibrate x=0, y=0; Alternatively, read the values on the rulers (arrows mark positiove direction, 4mm mark is 0)
Recalibrate z according to the value on the z ruler;
Use tilt to position back side of the manipulator head vertically --> recalibrate tilt=0;
Align the 2 vertical wires (left camera screen) by polar (correct for backlash) --> polar=0;
Rotate the sample towards the camera by polar and use azimuthal rotation to make sample holder top edge horizontal (correct for backlash) --> azimuth=0.
Press confirm.
After this axis coordinate will be saved and calibration panel will be locked automatically.
After recalibration your saved positions will not be very precise anymore because of the errors in determination of the positions. Center of rotation for polar map XY correctons may be also slightly shifted.