X-ray production and ionization energy

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SUMMARY

The discussion centers on the relationship between kilovolt peak (Kvp) and ionization energy in x-ray production, specifically regarding tungsten anodes. The Kvp in the x-ray machine is fixed at 65 kV, which is below the k-shell electron binding energy of tungsten at 69.4 eV. Despite this, the x-ray machine operates effectively due to the mechanism of bremsstrahlung radiation, where electrons decelerate upon striking the anode, producing x-rays. The confusion arises from the distinction between Kvp and the energy of the accelerating electrons, which is clarified through the concept of kinetic energy of photons (Kep).

PREREQUISITES
  • Understanding of x-ray tube components, including cathode and anode.
  • Knowledge of kilovolt peak (Kvp) and its role in x-ray production.
  • Familiarity with electron binding energy, particularly for tungsten.
  • Basic principles of bremsstrahlung radiation and its significance in x-ray generation.
NEXT STEPS
  • Research the concept of bremsstrahlung radiation in detail.
  • Study the differences between Kvp and kinetic energy of photons (Kep).
  • Explore the electron binding energies of various materials used in x-ray tubes.
  • Investigate historical developments in x-ray technology and tube design.
USEFUL FOR

Radiologic technologists, medical physicists, and anyone involved in the design or operation of x-ray machines will benefit from this discussion, particularly those seeking to understand the intricacies of x-ray production and ionization energy.

SakuRERE
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Homework Statement
what's the minimum kvp and kep required to generate x-ray?
Relevant Equations
nothing
I am confused with the Kvp and Kep.
I know that In the x-ray tube, after heating the filament and the electron cloud if formed, then the step-up transformer is going to increase the voltage and reduce the current to produce a high potential difference to that electrons will accelerate from the cathode to the anode. now, here comes the issue. the one that will determine the highest voltage is the Kvp (Kvp= kilovolt peak) with the help of the autotransformer. in our x-ray machine, the kvp is fixed and that is 65 kv. but isn't this not enough to cause ionization of the anode (tungsten). I searched about the k-shell (innermost) electron binding energy for the tungsten and it was 69.4. and I learned that for causing ionization of the innermost electron, the energy of the electron that will hit the tungsten should be either =or> than the electron binding energy. so, the hitting electrons should obtain either 69.4 or above kv. how come our x-ray machine works with kvp=65 kv.
I have a doubt that the kvp is not representative for the energy. if this is the case, then what is the unit or the concept that refers to the energy of the accelerating electrons? is it the kep?
 
Physics news on Phys.org
Ionizing inner shell electrons will create x-rays as an outer electron falls into fill the hole. However, that is not how the vast majority of x-rays in a typical x-ray machine are produced. X-rays are produced directly by the electrons flying from the cathode. As they strike the anode they encounter atomic nuclei and are rapidly deflected and decelerated. Accelerating (or in this case decelerating) charge creates light. See the Wikipedia article on bremsstrahlung.
 

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