What fraction of electron energy is converted to x-rays in kV units?

In the context of medical dosimetry, when electrons are accelerated and used in various therapeutic applications, such as in kilovolt (kV) X-ray machines, it is important to understand the conversion of electron energy to X-ray energy.

When the electrons strike a target, only a small portion of their kinetic energy is transformed into X-rays. This is primarily due to the inherent inefficiency of the conversion process, where most of the energy results in heat and only a minor fraction contributes to the actual X-ray production.

The fraction of energy converted to X-rays typically ranges around 1% to 10%, depending on various factors including the material of the target and the energy of the electrons. Hence, characterizing this conversion as "only a small fraction" accurately reflects the reality of X-ray production from electron beams in a kV system.

The options that suggest a significant fraction, about half, or all of the energy being converted to X-rays are misleading, as they do not align with the established principles of the physics of X-ray generation.