American Society for Nondestructive Testing (ASNT) Radiographic Testing Practice Test

The penetrating ability of an x-ray beam is primarily governed by kilovoltage. Kilovoltage (kV) refers to the voltage applied across the x-ray tube, determining the energy of the x-ray photons produced. Higher kilovoltage increases the energy of the x-rays, allowing them to penetrate denser materials more effectively. This is crucial in radiographic testing because better penetration means that the x-rays can pass through materials like metal and will reveal any defects or structures within the material being inspected.

While other factors like tube current, filtration thickness, and exposure time affect image quality and overall radiation dose, they do not fundamentally change the energy of the x-ray photons in the same way that kilovoltage does. Tube current influences the quantity of x-rays produced, filtration thickness alters the beam quality by removing low-energy photons, and exposure time determines how long the x-ray source produces the beam, but none of these factors are as pivotal in determining the inherent penetrating power of the x-ray beam as kilovoltage.