Module 2 - SEMs

Question 1

How SEMs work… (1)

Answer 1

A scanning electron microscope can be used to provide highly magnified views showing fine details of the surface of objects.

Question 2

How SEMs work… (2)

Answer 2

The specimen is mounted at the bottom of the microscope tower in a vacuum and a beam of focused electrons is moved over its surface by scanning coils.

Question 3

How SEMs work… (3)

Answer 3

Electrons striking the surface are scattered and some electrons are dislodged from the surface.

Question 4

How SEMs work… (4)

Answer 4

The scattered electrons are detected and their pattern is interpreted by a computer to produce an image on a monitor screen.

Question 5

How SEMs work… (5)

Answer 5

Although scanning electron microscopes produce highly detailed and magnified surface images, the resolution is less than that of images from TEMs.

Question 6

How SEMs work… (6)

Answer 6

Darker areas are caused by structures that have absorbed the electrons.