Scanning Probe Diffraction Quick Reference
Back to Diffraction
This reference is intended for general users, notify staff of necessary revisions or to request more detail
Prior to this section it is expected that sample alignment has been performed (Sample Alignment Quick Reference)
All MEDM windows below should be findable from the main beamline MEDM screen, to bring up this screen double click the desktop icon "26id MEDM" or type "start_epics" on a terminal screen
To process a new value in any MEDM command field the window MUST be selected (left click or double click) and the mouse MUST remain pointed into that field window UNTIL the user hits return
1) Setting up scan parameters
If necessary call up the scan1 and scan2 windows from the main beamline screen, these are under SCANS-DCM on the bottom left (hit the bottom right more button twice on each)
Remove prior positioner by double clicking the drive field until the text is highlighted, backspace, then return
Add a new positioner by middle clicking on the intended motor's command value field, holding the middle button down, dragging to the drive field in the scan window, release middle button, left click, then return
Select scanning range by EITHER adjusting the Start and End values OR adjusting the Center and Width values
Select scanning steps by EITHER adjusting the Step Size value OR adjusting the #PTS value on the top right of the window
Make sure the flags below the scan parameter fields are set to LINEAR, RELATIVE, and PRIOR POSITION (to set up other types of scans consult staff)
For additional positioners (ie to make a theta/two theta or runout corrected linear scan) click the green Positioners title box above the Read field, and follow the above five steps
To ensure the motion is completed, make sure the positioner settling time is at least 0.2sec - in many cases (soft motors, picomotors, or undulators) this should be at least 1 second
NOTES:
i) Do not use the "Clear positioners" button, this sets the scan type to "absolute" for all positioners
ii) An X next to the drive field should briefly flash if the new positioner is added correctly, and the units field should update to the new motor units
If saving images from the CCD make sure the change directory triggers are in the before scan and after scan placeholders in the scan1 window (consult with staff if absent)