Which of the following is NOT needed to produce x-rays?

To produce x-rays, several key components are necessary, among which are a high-voltage generator, filtration, and an x-ray tube. The high-voltage generator is crucial as it provides the electrical power needed to accelerate electrons from the cathode to the anode, while filtration is used to remove low-energy photons from the x-ray beam, thereby improving the quality of the radiation produced. The x-ray tube is the primary component where x-ray production actually occurs, housing the cathode and anode and facilitating the collision of high-speed electrons, resulting in x-ray generation.

In this context, a rotating anode, while beneficial for enhancing the efficiency and quality of x-ray production, is not essential for the generation of x-rays themselves. An x-ray tube can indeed function with a stationary anode to produce x-rays as long as the other components—high voltage and filtration—are present. Therefore, identifying the rotating anode as not necessary in the fundamental process of producing x-rays clarifies its supportive role rather than being a prerequisite.