What does an incident electron do at the tungsten target to produce characteristic radiation?

When an incident electron collides with a tungsten atom in the target, it can provide enough energy to eject an inner-shell tungsten electron. This process is crucial for the production of characteristic radiation. When the inner-shell electron is removed, the atom becomes ionized and unstable.

To restore stability, an electron from a higher energy shell (outer shell) drops down to fill the vacancy left by the ejected inner-shell electron. This transition from a higher to a lower energy level results in the release of energy in the form of X-rays. The energy of the emitted X-ray corresponds to the difference in energy between the two shells, hence the term "characteristic radiation," as the energy levels are unique to the element (in this case, tungsten).

This process is fundamental to how X-rays are generated in systems that utilize tungsten as a target material in radiography and radiation therapy. The characteristic radiation produced has specific energies that are diagnostic of tungsten, making it an essential component of X-ray production in medical imaging.