1. X-rays:
* When high-energy electrons (typically in the keV range) collide with the metal atoms, they can excite inner-shell electrons. When these excited electrons transition back to their ground state, they emit X-rays. This is the principle behind X-ray tubes used in medical imaging and other applications.
2. Heat:
* The electrons transfer some of their kinetic energy to the metal atoms, causing them to vibrate more. This increased vibration manifests as heat, which can be significant depending on the electron current and energy.
3. Secondary electrons:
* The incident electrons can also knock other electrons out of the metal atoms, creating secondary electrons. These electrons have lower energy than the incident electrons and can be emitted from the surface. This is the principle behind secondary electron emission, used in some vacuum tubes and detectors.
4. Light emission (cathodoluminescence):
* If the electrons have sufficient energy, they can excite the metal atoms' electrons to higher energy levels. When these excited electrons return to their ground state, they can emit light of specific wavelengths. This phenomenon is called cathodoluminescence and is used in some display technologies.
5. Surface modification:
* High-energy electrons can cause surface damage and even sputtering, where atoms are ejected from the metal surface. This can lead to changes in the metal's surface properties, such as its composition or roughness.
The specific phenomenon that occurs depends on the energy of the electrons, the material of the metal plate, and the vacuum conditions.
