Final answer:
CT scanner x-ray tubes use anodes composed of tungsten, molybdenum, and rhenium due to their high melting points, which allow them to withstand the heat generated during x-ray production.
Step-by-step explanation:
CT scanner x-ray tubes incorporate rotating anodes composed of materials that can withstand high temperatures due to the absorption of energy from high-speed electrons. Tungsten is commonly used as an anode material in x-ray tubes because of its high melting point. This allows it to endure the high temperatures when energetic electrons strike the target material, generating x-rays. When these electrons fill the inner-shell vacancies, they emit x-rays with large photon energies, characteristic of heavy elements—this process requires substantial accelerating voltage due to the tightly bound nature of inner-shell electrons.
Regarding the specific components of CT scanner anode materials mentioned in the options, the correct selection is tungsten, molybdenum, and rhenium (c). These materials are well-suited for their roles due to their high melting points and ability to endure the thermal stress involved in x-ray generation.