Passing through the ingredients, they surrender a certain amount of energy.
By adopting a distribution approach, in simple terms, we can say that when the γ rays pass through the ingredients, they surrender a certain amount of energy to them which depends on three variables: the number of γ producing an effect, their energy and the nature of the ingredients. The absorption of energy by the ingredients depends on the weight of the atoms that make them up and their density. The greater the atomic weight, the greater the absorption, the greater the number of atoms in the unit of space and the more interaction events there will be between the γ rays and the ingredients.
The absorption of energy mentioned above is nothing more than the irradiation dosage. The dosage unit of measurement is the Gy (Gray) which corresponds to a deposited energy of one joule per kilogram of ingredients. The effects produced on the micro-organisms are also linked to the presence of water in the cells.
The effects of radiation are produced on the unicellular organisms and with an even greater intensity on the multi-cellular organisms where the probability of striking and damaging the organism increases due to its increased size, and where it is enough to damage only a part of its cells to cause its death. The main direct effects involve the interaction with the DNA molecules causing their breakage and therefore blocking the cellular replication, but also damaging protein and lipid substrates that make up the membranes. The indirect effects are on the alteration of the metabolic processes which lead to the death of the cell, like the alteration of the RNA structure.
Other effects arise with unusual irradiation conditions which can generate the formation or breakage of chemical links and the achievement of states of arousal which provoke particular reactions. This technology allows for “cross-linking”, “curing”, polymerisation and intervention on the “thermal memory” of the thermoplastic materials. By contrast, breakages of certain chemical links (radiolysis) can also be achieved by generating reductions in the molecular weight of the macro-molecules or the elimination of unwanted substituents.