Introduction to the classification of transmission electron microscopes
1. Large transmission electron microscope:
Large transmission electron microscopy (conventional TEM) generally uses an electron beam acceleration voltage of 80-300kV, with different models corresponding to different electron beam acceleration voltages. Its resolution is related to the electron beam acceleration voltage and can reach 0.2-0.1nm. High end models can achieve atomic level resolution.
2. Low voltage transmission electron microscope:
The electron beam acceleration voltage (5kV) used in low voltage small transmission electron microscopy (LVEM) is much lower than that of large transmission electron microscopy. A lower acceleration voltage will enhance the interaction strength between the electron beam and the sample, thereby improving the image contrast and contrast, especially suitable for samples such as polymers and organisms; Meanwhile, low-pressure transmission electron microscopy causes minimal damage to the sample.
The resolution is lower than that of large electron microscopes, 1-2nm. Due to the use of low voltage, transmission electron microscopy, scanning electron microscopy, and scanning transmission electron microscopy can be integrated on one device.
3. Frozen transmission electron microscope:
Cryo microscopy typically involves adding sample freezing equipment to a regular transmission electron microscope, cooling the sample to liquid nitrogen temperature (77K), and observing temperature sensitive samples such as proteins and biological sections. By freezing the sample, the damage caused by the electron beam to the sample can be reduced, the deformation of the sample can be minimized, and a more realistic sample morphology can be obtained.
