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

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

Answer: (A)

Bremsstrahlung is the primary process by which x-rays are produced in diagnostic X-ray tubes. When the high-speed electrons strike the target material and pass near the nuclei, they slow down or are deflected, emitting photons as they lose energy. This deceleration produces a continuous spectrum of x-ray energies, up to the maximum energy of the incident electrons, which is why most photons in the beam come from this mechanism.

Characteristic radiation also occurs when an inner-shell electron is ejected and a higher-shell electron drops to fill the vacancy, emitting photons with energies specific to the target material, but this contribution is smaller and yields discrete lines rather than a broad continuous spectrum.

The photoelectric effect and Compton scattering describe how x-ray photons interact with matter after production, not how they are initially created.