Adding an X-Ray Linescan to the Acquisition

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Note: Only 4pi hardware that supports the "crossport" can do X-ray linescanning.
This includes all SEII v2.2 (and higher) cards.
All Universal Spectral Engine hardware supports x-ray linescanning.

This is a two-step process, as the linescan must be configured to use an internal SCA for its data source, and at least one element's ROI must be set to trigger that SCA channel.

First, open the SEM Linescan Preferences to set important linescan parameters. In Channel Options, select SCA#1 and set the acquisition to 16-bit (dwell). Choose the sequence (passing linescan shown), set the dwell and interpixel delay (10 msec and 1 µsec shown here, respectively), and change the name (presently unused) from the default, if desired:


The key here is selecting an SCA for the linescan source, rather than a default ADC (analog-to-digital converter).

Note 1: SEM Image channels can also use an SCA as their image source, providing an ersatz fast dot mapping capability. However, if this is done with more than one channel, Revolution will dwell for each channel sequentially, not simultaneously. In this mode, frame averaging will accumulate counts for each pixel rather than averaging them, as the number of counts collected in each frame will be small compared to the 16-bit (65536 value) capacity of each pixel.

Note 2: Although 8-bit dwell can be selected in the acquire menu, the data are acquired and transferred in 16-bit mode only; selecting the 8-bit mode will lead to spurious results. The interpixel delay value is generally irrelevant to x-ray linescans, and should be set to a minimum value (1 µsec). Also, be reminded that the linescan dwell is in units of microseconds, whereas x-ray linescans normally require dwells on the order of milliseconds or more - count your zeros!

Second, open the X-ray Image Prefs panel and select the Edit ROIs button:


The ROI periodic table will open; select the element for which a linescan will be performed (in this case Copper): x-ray_linescan_periodic

Shift-click to open the ROI definition for Copper and select SCA#1 from the SCA list:

The color of the linescan is set in the SEM Linescan Preferences above.

Repeat this process if you want a linescan that includes counts from more than one element.


The configuration of the linescan is now complete - hit OK to save the ROI definitions, and close the ROI periodic table (the preferences window can remain on-screen).

To include a linescan, click on the linescan button on the multi-toolbar:
linescan button

The next time an image is acquired, an x-ray linescan overlay will be added to the lowest logical channel window (typically Channel 1): linescan overlay in window