Scanning Electron Microscopy
Lab 4
Knobology on the FEI SEMs
Detectors
Machine: FEI Quanta and NovaNano
Samples: WC/Co; ductile iron
Objectives: To investigate advantages and disadvantages of different detectors
To learn how to operate the FEI Quanta and NovaNano
Time allotted: 1 week
Prelab questions: The WC/Co sample is flat, smooth, polished and conductive; it is embedded in a large plastic cylinder.
Is the plastic conductive? What do you do about it?
What values of accelerating potential, current, aperture size and working distance will you start with? Assume you will be working at 5kX; the interesting features of the ductile iron are visible at 1500 X. Justify your choices. (Don’t make this question any more difficult than necessary; the Quanta is set up to operate at 10 mm.)
How do you assure that you do not hit the pole piece with your sample while inserting it into the Quanta?
What does it mean “to link the stage”?
Why is it necessary?
When do you link the stage?
How do you link the stage?
What disasters can occur if you don’t link the stage (correctly)?
How do you adjust the stage position
a. To raise it while the system is pumping down
b. To move the stage horizontally to view a new area (minimum of three answers required)
Procedure: Investigate the microstructure of these samples using the Everhart-Thornley and backscatter detectors on the Quanta.
On the Quanta you will need to learn the specifics of inserting samples, adjusting the accelerating potential, probe current/spot size.
Your lab report should list similarities and differences between operations of the two machines.
Which are fundamental and which are “knobology”?
Your report should be in the form of a Standard Operating Procedure for the two detectors on the Quanta.
Include a drawing/description of how to move the stage to find a sample that is off center but at a specific location on your drawing of the sample holder.