Energy Conversion and Generation of X-rays
When an electron traveling at high speed strikes a target atom, it will be slowed or completely stopped by the gravitational forces of that atom (Figure 1). Based on the law of conservation of energy, the kinetic energy of the incoming electron cannot be lost. It must be absorbed by the atom or converted to another form of energy. About 99% of this kinetic energy will convert into heat, and the remaining will be radiating energy known as an x-ray.2,3,4,5,6
Figure 1. An electron traveling at high speed and abruptly slowed down or stopped. The kinetic energy will convert into heat and radiation.
When the gravitational forces of an atom completely stop the electron, the x-ray energy will be equal to the total kinetic energy of the electron. However, the gravitational forces will most times only slow down the electrons depending on their proximity to the nucleus. The closer the high-speed electron is the nucleus, the higher the x-ray energies are; this will result in a continuous spectrum of x-rays varying from very low energies to very high energies (Figure 2).7
Figure 2. Theoretical x-ray spectrum before filtration. There are more low energy photons than high energy photons.