EDS

The detection system may contain a set of detectors designed for detecting various signals resulting from electron beam interaction with the sample surface. The microscope is always delivered with the SE detector

• Beam Settings
  • Voltage Is specimen conductive (high) or non-conductive (low)? Beam-sensitive (low) or not? From what depth do you want signal to emerge, and which signal?
  • Current Is specimen conductive (high) or non-conductive (low)? Beam-sensitive (low) or not? Optimize signal (high) vs. resolution (low), choose small aperture (imaging) or large (x-ray).

  • Working Distance If not constrained by geometry of application, optimize resolution (low) vs. depth of field (high); signal may decrease at too long or too short W; when in doubt, operate at eucentric height.

    EDX should be done with a working distance of 15 mm

• Detector Settings

  Detector Type:

  • SE (topographic contrast, some Z)
  • BSE (atomic #, aka Z)
  • EDS/WDS (elemental composition).

  Using detector Bias, you can switch between different modes, please do not do so. Take one picture SE and one picture BSE. One might argue that the acquisition process for both are the same, but do it anyway, it makes life so much easier when you’re trying to plot it on a report.

• Alignments
  • Basic Technique: After gun tilt, iteratively adjust focus, astigmatism, lens alignment based on visual cues.
  • 1st Approximation (Focus/Stig): Use reduced area window w/longest dwell time that gives near-live refresh rate.
  • Perfected: Make comparisons using “alignment rectangle” in full frame or reduced window (integrate 1 frame).
• Scan Settings
  • Brightness & Contrast: Optimize using Videoscope at dwell/pixel capture settings. (try in full frame or line scan).

  • Live (single frame) vs. frame & line averaging/integration Frame averaging spreads out dose to mitigate charging artifacts, by averaging out the effects of a sudden flash. However, it does not overcome the general effects of charging and should be seen as a last ditch effort.

    Note: This is unusual for thermal spray coatings and anything conductive.

  • Scan Orientation: Change scan rotation to scan perpendicular vs. parallel to features; evaluate scan artifacts (is there image compression/stretching due to beam drift?) and mitigate charging artifacts.

Use outset graphs in EDX in order to show the change in composition

https://mmore500.com/outset/index.html

• Switch off the high voltage by clicking on the HV button in the Electron Beam panel.
• Remove your samples from the microscope.
• Pump the microscope.
• Close the program (use Exit from the File menu) select the Switch off (the microscope) and exit (the application) option.
• Wait until the VegaTC program closes itself. The microscope configuration will be automatically saved on the hard drive.
• Shut down OS Windows in the usual way.
• Turn the main switch to the left (OFF position).

• Use only one gloved hand when handling samples and holders
• Avoid letting the sample holder or any part of the sample exchange rod touch non-clean surfaces which may be contaminated with hand-oil
• Never “blow on” or exhale on samples to dry them, use the IR lamp instead
• Always make sure all screws are tight and that you always have a sure grip
• Always ask if you have a question

There are four factory presets for the accelerating voltage (5 kV, 10 kV, 20 kV, 30 kV), one for each HV index. The user does not need to make any further adjustments by switching among them and using magnification up to 4000x.

Click on the PUMP button in the Vacuum panel to start the pumping procedure (Figure 2). It usually takes around 3 minutes to reach vacuum ready - status which means that the microscope is ready to use. If there is a need to exchange the specimen, follow the instructions in chapter 8.2.

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In the SEM Detectors & Mixer panel select the appropriate detector from the list box (Figure 3). We recommend using the SE or BSE detector. When the BSE detector is used, make sure that the detector is not retracted! See chapter 6 for detailed infor- mation

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1. Select the accelerating voltage (30 kV recommended) using the combo box in the

Electron Beam panel (Figure 5).

1. Clicking on the HV button in the Electron Beam panel turns the high voltage on and

starts the heating of the tungsten filament (see Figure 5).

1. Right-click in the SEM Scanning window to open the menu and select the Minimum

Magnification function (Figure 6)

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7 Select RESOLUTION mode (click on the Scan Mode function in the Info Panel (see Figure 10) and select RESOLUTION or use the Continual Wide Field option – switches automatically between WIDE FIELD and RESOLUTION mode and vice versa when increasing or decreasing magnification)

Focus the image by clicking on the WD icon in the Toolbar and turning the Trackball from left to right (or vice versa). Alternatively use the Auto WD function for focusing (see Figure 6). Double-clicking (left mouse button) in the SEM Scanning window opens the Focus window. To remove the Focus window double-click anywhere in the SEM Scanning window.

To select beam intensity (BI 10 recommended), first left-click on the BI icon on the Toolbar and then use the arrows in the Pad panel (Figure 8).

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1. To select the sample position in the Stage Control panel, click on the appropriate

number button on the carousel (Figure 9) or use the manual knobs in the case of the SB microscope type.

1. Placing the cursor over the SEM Scanning window and clicking the mouse wheel

moves that area on the stage into the centre of the image. See chapter 7.2 for other mouse actions.

1. To magnify the image click on the Magnification icon on the Toolbar and turn

the Trackball from left to right.

1. Once the area of interest is magnified and focused as desired, right-click on the

Speed icon on the Toolbar and select the appropriate scanning speed.

1. Clicking on the Acquire button in the Info Panel (Figure 10) or on the icon

on the Toolbar saves the image. Fill in the note, sign and description field if necessary. Choose a folder in which to store the image. To change the parameters of the image use the Image Parameters function in the main SEM menu

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1. Clicking on the icon opens the dialogue for saving the actual adjustment of the

microscope. It is possible to restore the saved adjustment of the microscope later.

The best resolution is achieved at the highest accelerating voltage (30 kV) of the primary electrons.

1. Insert an appropriate sample for high magnification images (e.g. tin on carbon

sample, Figure 18).

1. Select the fourth HV index using the combo box in the Electron Beam panel (20 kV -

30 kV) and turn on the high voltage.

1. Focus the image in RESOLUTION mode (click on the Scan Mode function in the Info

Panel and select RESOLUTION or use the Continual Wide Field option). Note: Use the Degauss column function by means of the icon before changing WD&Z or WD. The image should remain in focus.

Check the spot size, which is determined by the BI value. Right-click in the SEM Scanning window to select the optimum BI value – Auto BI OptiMag.

1. For the best resolution, it is necessary to work at a short working distance (WD). The

optimum WD is about 5 mm for the SE detector (in the case that the BSE is not mounted underneath the objective lens). For BSE images the optimum WD is about 8.5 mm. To change the working distance together with Z-axis, without defocusing the image, use the WD&Z function in the Stage Control panel (Figure 15).

WARNING: Moving the manipulator with the specimen can cause it to collide with other inner components of the microscope and can cause damage to the microscope. Control the movements of the manipulator by video camera imaging (open the Chamber View by clicking on the icon). The manipulator’s movement can be stopped by clicking on the Stop button in the Stage Control panel (see Figure 15).

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Gradually magnify and focus the image to achieve 10kx magnification. In the case that the image is moving during focusing, it is necessary to check the centering of the objective. Select the Manual Column Centering function using the combo box in the Electron Beam panel after clicking on the Adjustment >>> button (Figure 16). The Manual Centering Wizard window will appear (Figure 17). Clicking on the WOB button opens the Focus window in the SEM Scanning window. Click on the Next>> button to obtain the next instructions. The function of the centering has two adjust- able values. To be sure just one value is changing, hold down the F12 key to change only X movement at the Trackball, and the F11 key to change only Y movement.

1. Each time that the image is too dark or light it is necessary to use the Auto Signal

function (see Figure 6 or use the icon ). To set the contrast and brightness manually, click on the icon and use the Trackball.

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At higher magnifications (>10kx) it is necessary to check if astigmatism (Figure 18 (a), (b)) is precisely corrected (Figure 18 (c)). To correct astigmatism click on the Stigmator function in the Info Panel (Figure 19). For precise correction use the Focus window (in the SEM Scanning window) and the F11 and F12 keys in the same way as in point 6.

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1. Select the appropriate scanning speed and save the image.
2. Clicking on the icon opens the dialog for saving the current adjustment of the

microscope. It is possible to restore the saved adjustment of the microscope later.

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The specimen should somehow be fixed or glued to the specimen stub before it is inserted into the chamber. It is possible to use 12.5 mm specimen stubs or any other specimen holders, delivered as microscope accessories (see chapter 9.7). If the specimen is examined in high vacuum mode, it must be conductive or must be made conductive using one of the methods described in the technical information. The conductive surface of the specimen must be conductive contacted to the stub. Non-conductive samples can be investigated in low vacuum mode. Instructions:

1. Vent the microscope by using the VENT button in the Vacuum panel. Wait until the pressure is at atmospheric level.
2. Set the tilt of the specimen stage to zero.
3. Open the chamber door by gently pulling it.
4. The automatic positions set up in the Stage Control panel can be used, which are intended for specimen position exchange. To select the sample position click on the appropriate number button on the carousel. At this time the button background is red to indicate the specimen exchange mode.