What is the name of the process by which an X-ray beam is reduced in intensity by absorption or scattering as it passes through material?

• A. ATTENUATION
• B. REFRACTION
• C. DIFFRACTION
• D. SCATTERRING

Answer: (A)

Attenuation is the process by which an X-ray beam loses intensity as it passes through matter. As the photons traverse material, some are absorbed (primarily via photoelectric interactions) and some are scattered (like Compton or Rayleigh scattering). The result is a reduction in beam intensity that can be described by I = I0 e^{-μx}, where μ is the material’s linear attenuation coefficient and x is thickness. While refraction describes bending of the beam due to changes in velocity in different media, and diffraction describes bending around edges or through apertures, and scattering refers to photons changing direction, attenuation specifically captures the overall loss of photons due to absorption and scattering that reduces beam intensity.