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Background

I set up my Scanning Electron Microscope (SEM) facility in early 2016 with three objectives in mind. These are:


What is an SEM?

An SEM is an instrument that is capable of providing highly magnified images of a specimen placed in the chamber of the microscope. Subjects may be biological, which is the type of subject I usually image, or more relevant to materials science or physics.

The SEM uses a beam of electrons to create the image of the specimen, rather than light as is used in conventional microscopy. The electron beam is scanned across the surface of the object and electrons released at the surface of the specimen by the interaction of the beam and the specimen are detected and used to create an image of the specimen’s surface. While an SEM is capable of producing much higher magnifications than light microscopy, or to be more precise, much higher resolutions, it is often used at magnifications of between x50 and x1,000 because it gives a much greater depth of field than is possible with a light microscope, as is illustrated below. Among the disadvantages of an SEM over a light microscope are the fact that an SEM is many times more expensive than a conventional light microscope and also, the image does not contain any colour information. Furthermore, it is necessary to dry the specimen without deforming it and then to coat it with a very thin layer of gold or similar conducting material before placing it in the chamber of the SEM.















Specification of the SEM

Key parameters of my SEM are as follows:













Specimen Preparation Equipment

My lab includes a Quorum E3100 Critical Point Drier and a Q150R ES Sputter Coater.

Further details on the SEM and specimen preparation equipment can be seen on other pages of this site - see navigation below or at the head of each page.

About this Site

The site is currently limited to seven pages, which can be accessed using the navigation bar at the top of each page or the links below:

Introduction

Make and Model

FEI Inspect S50

Detector 1

Everhart-Thornley secondary electron detector

Electron Source

Tungsten filament

Detector 2

Deben Backscattered Electron Detector

Available Modes

High vacuum

Low vacuum (variable pressure)

Detector 3

Large Field Detector (for low vacuum mode)

Best Resolution

3 nm at 30 kV

Digital resolution

4096 x  3536 pixels max

Computer operating system

Windows XP

Camera

Deben Chamberscope

Illustrating the difference of depth of field between an image from a conventional light microscope (left) and a scanning electron microscope (right). In the left hand image only a small fraction of the micro-fossil is in focus, whilst in the SEM image the whole specimen is in focus. Note also that the light micrograph is in colour while the SEM one is monochrome.