Transmission Electron Microscopy

A transmission electron microscope or TEM is used to study a sample's internal structure and composition.

The instrument consists of an electron gun which emits an electron beam. The beam is then focused on the sample using two or more electromagnetic condenser lenses.

The electrons transmitted through the sample are collected and focused by objective lenses to form the intermediate image. This image is further magnified by additional intermediate and projector lenses.

The final image can be captured using electron-sensitive imaging devices, such as a phosphorescent screen or CCD camera.

TEM forms a two-dimensional black and white image of a sample. Darker areas represent dense regions that transmit few or no electrons. In contrast, lighter areas indicate the regions through which more electrons are transmitted.

TEM is also used to analyze sample composition. The electron beam-sample interaction generates characteristic X-rays that can be used to identify and quantify different elements present in a sample.