AES Alignment Routine for Depth Profiles when using an Analog Multiplier Supply
The following procedure determines the correct multiplier voltage when you are
using an analog (for example, 20-075) multiplier supply to acquire an AES
depth profile.
- Select the New Depth Profile command from the Acquisition menu.
- In the Select Element dialog box, click on the elements for which you want to
acquire the depth profile. (If the element you want isn’t in the list, click on the New Element button to add the element to the
list.) Click on OK to close the Select Element dialog box.
- Click on the Apply button. This creates a new AugerScan document in which you
will be acquiring the depth profile containing the elements you just specified.
- Determine which of the regions in your depth profile has the highest kinetic
energy. To do this, open the Settings dialog box (click on the Settings button
in the Acquisition toolbar). Then, click on each region in the Regions list
and note the Lower Limit and Upper Limit for each region. For example, if your
depth profile contains the regions Carbon and Copper (Cu1), you would note that
Copper has a higher kinetic energy range (875 to 935) than Carbon (245 to 295).
Make a note of the lower limit and upper limit values of this element.
- Select the New Alignment command to display the Alignment Settings dialog box.
- Set the Upper Limit and Lower Limit energy settings in the Alignment Settings
dialog box to the values you noted above so that you sweep over the range of
the element with the highest kinetic energy. In our example, you would set the
Lower Limit to 875 and the Upper Limit to 935.
- Click on the Acquire button to acquire the alignment.
- Increase the multiplier voltage until you have 30% to 50% of the maximum allowable signal for your V/F preamplifier so that you get as much signal as possible without saturating the sample.
(Any particular element can dramatically increase its signal as a function of
depth. Setting the multiplier voltage to this lower level provides enough room
for this increase without signal saturation.) This is the multiplier voltage
your system will use to acquire a depth profile. Continue with the procedure for
acquiring an AES depth profile.
Note: This procedure can also be used for three-point depth profiles; instead of
noting the upper limits, however, note the background energies)