In terms of photon-electron interaction mechanisms, compare the photoelectric and Compton effects and define their energy and atomic number dependence at diagnostic x-ray energies.

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Marlene Welch · Accepted Answer

Quantum mechanics is a field of physics that started at the turn of the last century with Plank&#039;s theory of Blackbody radiation in which he suggested that light is transmitted in packets called quanta, with its energy dependent on the frequency of radiation. Einstein then confirmed the theory with his explanation for the Photoelectric effect for which he received the Noble Prize. Compton effect was scattering of photon like Rayleigh&#039;s scattering but at higher energy level making quantum effect dominant.The Photoelectric effect and Compton effect are two phenomena where photons interact with electrons. So, we can discuss both the phenomena and their differences. Photoelectric effect: In this effect, photons hit the electrons bound in atoms at the surface to release photoelectrons. The energy balance in this process is given by the following relation.       E    e    =  h  v  −  ϕHere,   ϕ is the work function of the metal,        E    e   is the energy of the electron, hv is the energy of the incident photon. Compton effect: In this effect, the high-energy photons hit the electrons so the electrons are released from the atoms.      E    e    =  h  v  [                              h          v                                      m            0                                c            2                              (      1      +      cos      ⁡      θ      )              1      +                        h          v                                      m            0                                c            2                              (      1      +      cos      ⁡      θ      )        ]Here,       m    0   is the rest mass of the electron, hν is the incident photon energy.  θ is the angle between the incident beam and the scattering beam.Differences between Photoelectric effect and Compton effect. In the Compton effect, the energies of photons are much higher than in the Photoelectric effect. The atomic number dependence of the Compton effect is negligible whereas the photoelectric effect increases with an increase in atomic number. Atomic number and energy dependence. Photoelectric effect:The probability of absorbing the photon.   p  ∝            Z      n              (      h      v              )        2            Here, n is a factor, Z is the atomic number.It is clear that the probability increases with increasing atomic number and decreases as the energy of photon increase in X-ray range. Compton effect:  The probability is not dependent on atomic number and it also decreases with increases in energy in higher photon energy ranges.

In terms of photon-electron interaction mechanisms, compare the photoelectric and Compton effects and define their energy and atomic number dependence at diagnostic x-ray energies.

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