Nuclear & Particle Physics - Internal Conversion

Internal conversion is the process whereby an excited nucleus transfers its energy directly to one of the most tightly bound atomic electrons, causing the electron to be ejected from the atom and leaving the atom in an excited state. The most probable process after an internal conversion electron is ejected from an atom with a high atomic number is that the

1. atom returns to its ground state through inelastic collisions with either atoms
2. atom emits one or several X-rays
3. nucleus emits a gamma-ray
4. nucleus emits an electron
5. nucleus emits a positron

(GR9677 #10)

Solution:

Electron transitions in atom (internal conversion) = X-ray production
→ An orbital electron is absorbed and ejected along with an X-ray

compared to:

Nuclear transitions = Gamma, γ Ray production

→ The excited nucleus jumps to a lower level and emits a photon γ

Answer: B

Note: 

1. (C), (D), and (E) are products of radioactive decay which are results of unstable nuclei.

2. In internal conversion:

• For low atomic number, it will produce the Auger effect and ionize the outside electron.
• For high atomic number, it will only emit X-rays.