X-Ray Sources

X-Rays | | X-Ray Radiography

X-Rays are created, when electrons are emitted from a cathode of a vaccuum tube and accelerated by a high voltage potential between the cathode and anode and finally hit the anode. At the anode the gained energy of the electrons is released as thermal energy and electromagnetic energy (a few percent). Due to high temperatures the anode is usually made from Wolfram.

There are two main physical effects that lead to the appearance of X-rays:

  • “Bremsstrahlung” by a slow-down of electrons in the atomic Wolfram metal grid.
    • Broad frequency range depending on electron motion energy.
  • Characteristic radiation by lifting an electron of the Wolfram atom on a higher energy level. When the electron falls back to the lower level, the energy difference is emitted as a photon.
    • Emitted electron energy is characteristic for the anode material.

X-Rays | | X-Ray Radiography