Question

Compare the production of bremsstrahlung and characteristic radiation.  Describe the specific contribution that each type makes to the x-ray emission spectra (the intensity vs. photon energy graph).  Finally, identify all major factors affecting the curve’s shape and position.

Answer 1

To compare the production of Bremsstrahlung and Characteristic radiation which is given below as :

Bremsstrahlung Radiation = "Bremsstrahlung" means "braking radiation". It describes the radiation which is emitted when electrons are decelerated or "braked" when they are fired at a metal target. The bombarding electrons can also eject electrons from the inner shells of the atoms of a metal target. Those vacancies will be quickly filled by an electrons dropping down from higher levels which gives rise to sharply defined characteristic x-rays.

Characteristic Radiation = "Characteristic radiation" are emitted from heavy elements when their electrons make transitions between the lower atomic energy levels. The bombarding electrons can eject electrons from the inner shells of the atoms of a metal target. Those vacancies will be quickly filled by an electrons dropping down from higher levels which emitting x-rays with sharply defined frequencies associated with the difference between atomic energy levels of the target atoms.

Describe the specific contribution that each type makes to the x-ray emission spectra (the intensity vs. photon energy graph).

Bremsstrahlung radiation is a continuum with maximal energy at a keV = tube kV. The most photons produced occurs at 0 keV and almost no photons are produced at keV = kV. Characteristic radiation are due to electron ejection events. The hole is filled by another electron which emits an x-ray at a specific frequency.

Each element will have one or a couple relevant characteristic x-rays which are produced at a higher rate compared to the Bremsstrahlung at any frequency (but with a very narrow peak). Because of tube filtration, the very low energy photons are removed and do not reach the patient.