What material are the target and filament in the x-ray tube primarily made of?

The target and filament in an X-ray tube are primarily made of tungsten due to its exceptional properties that are ideal for producing X-rays. Tungsten has a high atomic number, which is critical for effective X-ray production because higher atomic number materials produce more efficient X-ray photons. Additionally, tungsten has a high melting point (around 3,422 degrees Celsius), allowing it to withstand the intense heat generated during the rapid deceleration of electrons when they collide with the target. This high thermal conductivity also helps in dissipating heat, preventing damage to the tube assembly during operations.

The other materials listed, such as gold and silver, while they have desirable conductive properties, do not match tungsten in terms of melting point and efficiency in X-ray production. Copper is often used in other components of the X-ray tube, like the anode and the housing, but it does not provide the same benefits for the target and filament as tungsten does. Thus, tungsten remains the preferred choice because of its unique balance of physical and chemical characteristics that support the functionality and efficiency of the X-ray machine.