What component is added to the tubehead to reduce the size of the x-ray beam?

The component that is added to the tubehead to reduce the size of the x-ray beam is the collimator. A collimator functions by narrowing the beam of x-rays emitted from the tubehead, which helps to limit the exposure area and minimize unnecessary radiation doses to surrounding tissues. By focusing the x-ray beam to the area of interest, the collimator enhances image quality and reduces scatter radiation, leading to more precise diagnostic outcomes.

In dental radiography, using a collimator is crucial for patient safety and for adhering to radiation protection standards. The other components mentioned, such as filtration, rectifiers, and transformers, serve different purposes within the x-ray machine and do not specifically reduce the size of the x-ray beam. Filtration, for instance, is intended to remove low-energy x-rays from the beam, improving image quality and safety without affecting the size of the beam directly.