What percentage of the total energy applied to an x-ray tube target is converted into x-rays?

The process of generating x-rays in an x-ray tube is inherently inefficient. When high-energy electrons strike the x-ray tube target, a fraction of their energy is converted into x-ray photons, while the majority of the energy is dissipated as heat.

Typically, only about 1% of the total energy applied to the x-ray tube target is transformed into useful x-rays. This means that the majority of energy—approximately 99%—is lost as heat rather than being converted into x-rays. Therefore, the selection of 99% accurately represents the large amount of energy that does not contribute to the generation of x-rays, highlighting the inefficiency of x-ray production.

Understanding this energy conversion process is crucial for x-ray machine operators, as it underscores the need for effective cooling systems to manage the heat generated and to maintain the performance and safety of the x-ray equipment.