Which of the following is the primary process by which x-rays are produced?

• A. Characteristic
• B. Compton effect
• C. Bremsstrahlung
• D. Photoelectric

Answer: (C)

X-ray production in an x-ray tube mainly comes from the deceleration of fast electrons as they pass near the nucleus of the target atoms. This braking radiation, or Bremsstrahlung, creates a continuous spectrum of photons with energies from near zero up to the maximum set by the tube voltage. Another mechanism, characteristic radiation, occurs when an incident electron ejects an inner-shell electron and electrons from higher shells drop in to fill the vacancy, emitting photons with energies fixed to the target’s atomic structure. The other two interactions—Compton scattering and the photoelectric effect—are ways photons interact with matter after production (scattering and absorption), not how the X-rays are generated.