Transmission Electron Microscope Operation

This training activity provides theoretical and hands-on instruction in the safe operation of a transmission electron microscope (TEM) for the examination of biological and material samples.

Participants are introduced to the basic principles of electron microscopy, the main components of the instrument and the procedures required to obtain high-quality and reproducible images.

The training covers:

• Basic principles of transmission electron microscopy

• Main components and functions of the TEM

• Laboratory safety and instrument-use procedures

• Verification of microscope status and operating conditions

• Vacuum system fundamentals

• Selection and insertion of specimen grids

• Correct use of the specimen holder

• Sample introduction and removal

• Electron beam generation and control

• Adjustment of accelerating voltage according to instrument protocols

• Beam alignment and centring

• Condenser lens adjustment

• Control of beam intensity and illuminated area

• Selection of magnification

• Image focusing and correction of astigmatism

• Selection of suitable sample areas

• Bright-field imaging

• Use of apertures

• Image acquisition using digital cameras

• Adjustment of exposure and image-acquisition parameters

• Image storage, organization and basic processing

• Recognition of sample-preparation and imaging artefacts

• Prevention of sample damage caused by the electron beam

• Identification of contamination, charging and drift

• Basic troubleshooting

• Correct shutdown and specimen-removal procedures

Specimen Examination

Participants learn how to systematically examine TEM grids, beginning at low magnification to assess section quality and identify suitable regions of interest. They are then trained to progressively increase magnification and optimize focus, contrast and illumination conditions.

Special attention is paid to:

• Assessing the quality of ultrathin sections

• Identifying folds, knife marks, compression and staining precipitates

• Recognizing cellular and subcellular structures

• Selecting representative areas for image acquisition

• Avoiding excessive electron-beam exposure

• Maintaining consistent imaging conditions between samples

Image Acquisition

The training includes the acquisition of digital TEM images for qualitative and quantitative analysis. Participants learn how to select appropriate magnification, resolution, exposure and contrast settings according to the objectives of the study.

The importance of recording relevant image metadata is also addressed, including:

• Sample identification

• Magnification

• Scale information

• Accelerating voltage

• Imaging conditions

• Date of acquisition

• Experimental treatment or sample group

Safe and Autonomous Use

TEM operation requires specific training because the instrument contains high-voltage components, vacuum systems and highly sensitive electron-optical elements.

Independent use of the microscope is only permitted after:

• Completion of the required theoretical and practical training

• Demonstration of correct specimen handling

• Demonstration of safe instrument operation

• Successful acquisition of suitable TEM images

• Approval by CTEM technical staff

• Compliance with CTEM safety and equipment-use procedures

Depending on the complexity of the experiment and the level of user experience, TEM sessions may require supervision or direct assistance from CTEM technical staff.

At the end of the training, participants will be able to understand the basic operation of the transmission electron microscope, handle specimens correctly, optimize imaging conditions, acquire digital images and recognize the most common technical and sample-related artefacts.