X‑ray Production: How X‑ray Tubes Generate X‑rays

X‑rays are produced in X‑ray tubes via a vacuum chamber by accelerating a high‑energy electron beam onto a metal target, typically tungsten. When high‑speed electrons strike the target, their kinetic energy is transformed into two forms: heat (about 99%) and X‑ray radiation (about 1%).

Only a narrow, specific wavelength range from this 1% emitted energy passes through the tube window—which consists of beryllium in high‑power X‑ray tubes and aluminum in diagnostic imaging machines. This filtration produces the usable X‑ray beam.