How does the probability of pair production in the interacting medium vary?

How does the probability of pair production in the interacting medium vary?

• A. Inversely with energy
• B. Linearly with photon energy
• C. As Z^2
• D. As E^2

Answer: (C)

The probability of pair production is influenced significantly by the atomic number (Z) of the interacting medium. The process of pair production, which occurs when a photon with sufficient energy interacts with the electromagnetic field of a nucleus, leads to the creation of a particle-antiparticle pair, typically an electron and its anti-particle, a positron. The likelihood of this occurrence increases with higher atomic numbers due to the stronger electromagnetic fields present around heavier nuclei. This is where the relationship proportional to Z^2 comes into play, as it captures the greater probability of interaction in materials with higher atomic numbers. The Z^2 dependence arises from the fact that the cross-section for pair production is particularly sensitive to the electric charge of the nucleus, which is represented by Z. Consequently, in environments with high-Z materials, there is a much higher chance of photon energies being converted into pairs since the availability of the nuclear field to facilitate this interaction is greater. This characteristic makes the response to Z^2 a key factor in understanding pair production dynamics in terms of material choice for various applications, like radiation shielding or in medical treatments using high-energy photons.

The probability of pair production is influenced significantly by the atomic number (Z) of the interacting medium. The process of pair production, which occurs when a photon with sufficient energy interacts with the electromagnetic field of a nucleus, leads to the creation of a particle-antiparticle pair, typically an electron and its anti-particle, a positron.

The likelihood of this occurrence increases with higher atomic numbers due to the stronger electromagnetic fields present around heavier nuclei. This is where the relationship proportional to Z^2 comes into play, as it captures the greater probability of interaction in materials with higher atomic numbers. The Z^2 dependence arises from the fact that the cross-section for pair production is particularly sensitive to the electric charge of the nucleus, which is represented by Z.

Consequently, in environments with high-Z materials, there is a much higher chance of photon energies being converted into pairs since the availability of the nuclear field to facilitate this interaction is greater. This characteristic makes the response to Z^2 a key factor in understanding pair production dynamics in terms of material choice for various applications, like radiation shielding or in medical treatments using high-energy photons.