Electron

Electron is one of elementary particle that constitutes a substance, and one of repton that has negative unit charge. Its mass is about 511keV. For example, it is accelerated at 200kV by Electron microscope, then it has much kinetic energy as same mass energy. Therefore, it is required to consider Relativistic effects.

Wavelength:

Acceleration voltage	Wavelength
200kV	2.507pm
100kV	3.700pm
80kV	4.174pm