Friday, September 23, 2011

Scanning Electron Microscope Tutorial

Using a scanning electron microscope.


Scanning electron microscopes (SEM) use a beam of electrons instead of light to view specimens. The beam of electrons produces signals at the surface of specimens that show the external morphology. In addition, the SEM allows you to see the shape, size and position of the particles that make up the object in a two dimensional image. The size of areas that can be imaged in the scanning mode range from 1 cm to 5 microns and the magnification ranges from 20 times to about 30,000 times.


Instructions








Inserting the Specimen


1. Insert your specimen into the cylinder specimen holder. Make sure you adjust the specimen surface with the top of the cylinder. Put the set screw in to hold the specimen in place.


2. Double check that the filament emission knob is turned off, as well as the Accelerating (Accel) Voltage button. You can find the knob and button on the second control panel. To verify the knob is turned off, make sure it is turned completely to the right. The lamp button will go out when the Accel Voltage is off.








3. Pull the exchange rod back and place the entire assembly into the chamber. Press the vacuum control button.


4. Open the specimen exchange chamber isolation valve by turning it to the right. Unscrew the rod and take it out very carefully.


5. Push the isolation valve in and press the vacuum control button again.


Generating the Electron Beam


6. Turn up the brightness and contrast knobs. Follow the manual for your scanning electron microscope on the procedure for scanning.


7. Press the Accel Voltage button and emission knob. Focus the scan line for better detail using the focus knob. Adjust the contrast and brightness as well.


8. On the control panel of your microscope, press the picture button, which should be labeled PIC. This will present the image of your sample.


9. Remove the specimen, following the same directions as inserting the specimen.

Tags: Accel Voltage, Accel Voltage button, beam electrons, control button, control panel, emission knob, isolation valve