EDX Image (X-ray Mapping) Mode

The EDX Image Toolbar

EDX image display and acquisition functions are controlled from the EDX Image Toolbar. If the toolbar is not visible at the top of your screen, selecting Mode → EDS Image from the top menu will make it appear:


Before configuring and performing an acquisition that could take hours, one should ascertain that the basic system is configured and operational. The user should verify beforehand that there is no problem either with acquiring an image or a calibrated spectrum. This page will assume knowledge on the part of the user about both of these procedures.

Note: the EDX image capability in 1.6 is significantly different from all previous versions of Revolution. The installer's setup procedure is described below, but the user will rarely need to adjust these settings. In particular, preselecting elements, although it can be done, is not generally necessary as it was in Revolution versions before 1.6.0.

First Run - Initial Configuration

Resolution is set straight from the toolbar:

set rois

To configure most settings for EDX imaging, hit the Setup button in the middle of the toolbar to get this window:

set rois

Acquiring the Maps

Press the acquire button (camera icon) to start the acquisition. A container will open and show the selected maps as they are being acquired (example below). The container is fully resizable and is interactive in real time. A full spectrum at every pixel is acquired, as well as the entire chronological history of the acquisition. For this reason, no actual setup other than described above is required: the user can acquire an entire data set, and then select which maps to display after the fact.
Using the resize box in the lower right corner, the user can resize the container interactively at any time during or after the acquisition:

Tip: using File → Copy, an image of the container can be placed in the clipboard buffer of the operating system, and pasted into another program.

Real-Time Map Interaction

The user can interact with the maps in real time in the following ways, all by right-clicking in the container and selecting from a variety of contextual menu options:

Operating note: selecting any of these will NOT stop the acquisition. It will continue in the background. When the changes are completed, they will be incorporated into the container as if they had been selected originally.

choose color There is no need to restart the mapping, even after the mapping is finished!!

Each of the items in the contextual menu is described below.

Extracting Spectra

At any time during a map acquisition (or after), spectra can be extracted from any set of pixels in a map container. The spectra will appear in new live windows that can be operated on independently, all while the acquisition of data continues. From the toolbar, select any of the extraction geometries (point, line, rectangle, polygon) and place them in any map or image in the container. Points are a single click. Lines and rectangles are click-and-drag. Polygons are multiple clicks, one at each vertex, and a final double-click to close the shape:

extraction tools

After any particular tool shape is placed in the container, right click on that shape and select Extract Spectrum:

The extracted spectrum will appear with a reminder image that can be moved or resized:

To quant the spectrum, right-click anywhere in the window and select Quantify:

The final result is an independent window with a quanted spectrum from only that selected area:

The number of spectrum windows that can be extracted in this fashion is unlimited. Each will be an autonomous live window that continues to acquire data and can be manipulated independently of all other extractions and the container; however, all extracted windows will be linked to their particular container. New containers, all with their own set of linked autonomous live extracted windows, can of course be opened as well.

Saving Containers

Either by clicking on the container-window close box or selecting File→Save, the standard save dialog window will appear; two saving choices are available:

Flatten Frames (the default) will compress all time history out of the event file. Subsequent reopening will include the full 3-D data cube, but not the history; therefore, no further Spatial Frame Locking is possible in such a file.

All Frames will save the entire event stream to disk, allowing a complete replay of the acquisition, frame by frame. In this mode, Spatial Frame Lock can be toggled on and off.

Note: As a basic rule of thumb, flattened files will occupy 4-5 times less disk space than entire event files.

Dwell Time Operating Note

The most common complaint about acquired x-ray maps is "nothing was acquired; the map is black." This is invariably because the physics of the acquisition process has not been considered. As an example, consider an output count rate of 2000/sec. This is counts into the entire spectrum. If the spectrum consists of 2000 channels, this is an average of one count per second per channel. A typical spectrum might have most of the counts concentrated in 5 ROIs, so there are perhaps 400 counts/sec going into each ROI. A dwell time of 10 millisec per pixel then yields, on average, 4 counts per ROI per pixel when the map is finished. When autoscaling, this is enough to create a visible map; however, if the map is not autoscaled, or if the count rate or dwell is not large enough, the maps will be black. Always do a back-of-the-envelope calculation to see if your acquisition conditions make sense!!

Fast Mapping Operating Note

The dwell time operating note is even more important in the case of fast mapping, because the mapping is proceeding at the scan rate for SEM imaging (typically 1000 times faster). As a result, there are usually no x-ray counts to be recorded at any particular pixel. In this case, the dwell should be set to either 2 or 3 times the pulse processor time constant. Furthermore, since frame averaging is usually used with fast mapping, the dwell times for the video images can be set to a small value. If allowed by your measurement environment, we also suggest adjusting spot size and/or aperture to significantly increase the count rate (40-50% deadtime is not unreasonable).