What do you understand by Radiolysis of Water Vapour?

One of the best examples for understanding the concept of radiation chemistry is Radiolysis of Water Vapour using gamma radiations.

Some of the major products of Radiolysis of Water Vapour are as follows:

a) Free radicals like •H , •OH , •HO₂

b) Positive ions like H₂O⁺ , H₃O⁺

c) Hydrated electron i.e. e^– (aq)

d) Molecular species like H₂ and H₂O₂