red = needs attention

italics = drafty language

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Figure 1. The SNE-4500M Plus with numbers denoting the key interactions for a user. Image from the SNE-4500M Plus user manual at www.seceng.co.kr

I. Introduction

What is the SEM? What does the SEM do? What are additional resources (link them here)

Can steal some of the text out of the Hitachi User Guide (explaining how SEMs work)

For EDS, first follow this Quick Start Guide and then proceed to (link)

II. Procedure

A. Sample preparation and loading the sample

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1. Push the ‘power switch’ on the left-hand side of the microscope (Figure 1.2).  
2. Launch the Nanoeye software icon (Figure 2) on the desktop to launch the program 
3. Prepare your sample for SEM analysis. Depending on the size and material, this may require gold/palladium sputter coating or carbon-coating (used for EDS). For sputter/carbon coater instructions, see the Sputter Coating Quick Start Guide.
   
   1. Common sample types include: stubs, with or without sputter coating; thin-sections with carbon coating; grain-mounts with carbon coating.
   2. Somewhere need to explain that coating is to prevent charging, which is especially common with thin-sections. Show a picture. Can copy some of the text out of the Hitachi SEM user guide
4. Using the jig (Figure 3), measure the size of the specimen including mount. Use the gradations of the horizontal grid on the jig to measure the diameter of the specimen and the vertical grid for the specimen height. If you are using older 3.2mm style stubs with a narrow attachment post, there is an adapter available to fit into the stage. Make sure to measure dimensions with the adapter attached.
5. Important: use compressed air to blow off any loose material on the sample that otherwise could be mobilized within the vacuum and damage the detectors.

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1. When not in use, the SEM is typically left under vacuum. Thus, to load a sample, the SEM needs to be pumped with air. Press the Exchange button on the front of the SEM, which will activate the vacuum and evacuate the chamber. Press the Exchange button again to initiate the SEM filling with air. The button LED light indicates the inner vacuum status of the chamber, and the signals are: 
   1. Light Off: Vacuum is not applied
   2. Light On: Vacuum is applied
   3. Slow blinking: Vacuum is being released
   4. Fast blinking:  Vacuum is being applied
2. Follow the LED strip on the front of the SEM which is a progress bar, with a fully illuminating LED strip indicating that the SEM is at vacuum. Listen for a double? beep, which indicates that the vacuum has fully been released.
3. Fully open the stage door and click the ‘Calibration’ button to initiate the stage motor calibration (Figure 4). This should take around 3 minutes, and all motor controls will go back to the home position when done and no numbers should be yellow.? Occasionally the motor will get stuck at its limit switch and the value will stay yellow, in which case you can run the Calibration routine again.
4. In the Nanoeye software, click the “Sample Information” text box (Figure 4, red rectangle), enter the height and width values, then press Enter. Important: The command will not be registered if the user fails to hit Enter. After the  After the height is entered, the Z-axis will automatically lower the stage to accommodate for the entered height to a distance of Z = [Entered height]. . Important: The command will not be registered if the user fails to hit Enter, and the user runs the risk of colliding the sample into one of the detectors.

Figure 4. Nanoeye window showing the sample preparation commands. Enter the height and width into the Sample Information (red box).

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1. 1. Use a 1.5 mm allen wrench to carefully loosen the set screw, then insert the mount with the specimen to the stage, and tighten the set screw (Figure 5).
   2. Important: Ensure that stub (+/- adapter) is seated fully into the stage mount. Use caution when loading samples to prevent accidental collision with detectors. Gloves should be worn when handling any components/sample material that goes into the vacuum chamber. IMAGE GOES HERE Skin oil and loose debris can damage the detector. Stubs should be prepared with gloves. For thin-sections and grain mounts, they should be wiped with isopropanol. It may be beneficial to leave a grain mount overnight in a vacuum or dessicator cabinet, as in particular, grain mounts the larger quantity of epoxy can de-gas water vapor and other volatiles.
   3. If you lose the set-screw, there are a few spares in a small ziploc bag in the clear case with SEC SEM accessories.

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1. Once the machine is under vacuum (indicated by the SEM beeping twice), navigate to the Operation Panel (Figure 7). IMAGE GOES HERE 

2. Select an accelerating voltage (range: 1 to 30 kV; see table 1 for working guide).

   1-5 kV	Delicate or uncoated samples (e.g. microfossils)
   5-10 kV	Coated biological samples (e.g. Au coated microfossils, recommended)
   10-30 kV	Carbon-coated thin section samples

   Table 1. Working guide for accelerating voltage 

   
   

   Figure 7. Operational start-up window

   
   

3. Select which detector to use:
   1. the secondary electron (SE) detector, which returns an image of the topography of the sample's surface and is generally used for micropaleontological identification with SEM stubs
   2. or the back-scattered electron (BSE) detector, which returns a pixel value based on the average atomic number (Z) of a given material and is generally used on thin sections or grain mounts.
   3. User guide can have a more in-depth explanation of the two different detectors and show samples of SE and BSE images, how they work.
4. Click the START button to generate an the electron beam (Figure 7). 
5. Monitor the emission current, which should be around 110uA. If it has diverged by more than ±20 uA, please notify a technician as this either means the filament is about to die or the beam is not stable, and image quality will be subpar. how to change the filament

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