Sample Alignment

22ID or 22BM

Sample alignment is accomplished on both 22BM and 22ID by use of the SERgui sample page (shown below). The user can either use a manual or automated protocol for sample alignment.

The sample environment consists of 2 visualization cameras (1 below the sample pointing up (bottom) and 1 pointing along the beam direction either 30 degrees(BM) or 45 degrees (ID) from horizontal (top)) and the sample goniometer. The sample goniometer has a number of remotely controllable adjustments:

(1) Entire assembly vertical

(2) Entire assembly horizontal (inboard outboard)

(3) Sample z (along same direction as (2))

(4) Sample x and y (defined by camera and phi position)

The sample alignment procedure uses the sample x, y, and z motions to place the sample at the defined sample position, marked as the red crosshair on the sample page. The x and y motions are provided by a pair of cross mounted slides, which when coupled with the appropriate phi position align 1 set of slides to be parallel and 1 set of slides to be perpendicular to the camera being used.

Manual Sample Alignment

The Alignment section of the Sample Page can be used to manually align the sample. The Phi angle can be changed to 1 of 4 orientations, whose phi positions are independently defined for the 2 cameras, which can be changed by pushing the appropriate button:

Top: +x (0), -x (180), +y (90), and –y (-90)

Bottom: +x (60), -x (240), +y (150), and –y (-30)

These phi positions have been predetermined to properly orient the 2 stages (x and y) such that the point and click alignment and fine adjustment buttons will function properly. To align your sample all you have to do is rotate the sample and use the point and click or fine adjustment buttons (or both) to center your sample on the red cross-hair.

Point and Click: Move the mouse crosshair to the point on the image that you want to bring to the red crosshair and click the left mouse button. Repeat this process as needed to align your sample. The point and click alignment can be used with either camera, as well as the X2 zoom capability for the top camera.

Fine Adjustment Buttons: The fine adjustment buttons can be used to perform single relative moves of the sample. The size of the move is selected by using the selection box in the Fine Adjustment section of the GUI – note that only the values selectable from the pull down menu are available. Once the size of the step has been selected just push the appropriate button and the sample will move. Note that for small adjustments, theses buttons are faster than the point and click procedure.

Light Control: The scroll bars on the right hand side of the sample image labeled Lights control the light levels for the two available light sources. These light levels can be adjusted to optimize the image contrast.

NOTE: If you move in the direction of the backlash correction, you will see a large move in that direction followed by your requested move.

Automated Sample Alignment

The AutoAlign section provides 3 different functions. The save image Snap button will capture a JPEG of the displayed image and place it into your log file. The Lights On/Off button will place the white back scatterer into or out of position to provide a uniform image background – note that the back scatterer is either automatically inserted (for auto align) or removed (data collection) when necessary. The Align button will perform an optical alignment of your loop; first using the bottom and then the top camera. An example is shown below.

Misaligned loop bottom camera view.

Misaligned loop top camera view.

Result of auto align procedure.

The status of the auto alignment procedure will be displayed in the terminal window that you started sergui in. Once the auto-align procedure is finished, the user can still use either the point and click method or the fine adjustment buttons to improve optimize sample alignment. The system will attempt to center the loop, not the sample, so the more closely you match loop to sample size, the more accurate this procedure will be.

The auto alignment procedure can freeze the video display in sergui, but the motion can be viewed in the beamline or remote video displays.

NOTE: For the auto-align procedure to function properly, the loop must be in the field of view of the bottom camera.

Disable/Enable Sample Video

The sample video feeds into sergui can be turned on and off. The disable button in the Camera Selection section will disable the video feeds, which can be very useful for remote users that are having a problem with their bandwidth – i.e. slow response on the sample page. Remote users should become familiar with the web based video feeds for viewing the sample and experimental hutch (robot). If you are having a problem with your remote connection, then you can disable the video feeds and use the auto-Alignment and fine adjust buttons to align your sample. The video feeds can be enabled by selecting either the Top or bottom camera buttons. If the video feeds are disabled and you attempt a point and click procedure, a message window will pop up telling you that the feeds are disabled and that you must enable the feeds for this capability.

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We welcome your questions and comments. Send e-mail to: SER-CATwebmaster@anl.gov