Remove fungi, larvae, insects and bacteria
The irradiation by gamma rays also protects distant remains of the past from degradation by eliminating fungi, larvae, insects and bacteria. Gamma rays from cobalt-60 or coming fronm a small accelerator are a tool for eliminating, without heating and with great reliability, fungi and parasites.
From a biological perspective, an intense gamma irradiation causes damages to DNA molecules, the seat of the genetic information of microorganisms. It interacts with the entire cell, causing the destruction of organisms. The radiation is very penetrating and radiating throughout the treated volume. It does not require the use of chemicals and can be made at ambient temperature and pressure. An object need not be removed from the package that was used to transport it. The mummies may remain in their coffin.
Ramses II mummy
The most famous disinfection by gamma irradiation is that of the Pharaoh Ramses II mummy, which was infested with larvae and fungi. The irradiation was preceded by numerous tests on other mummies, to verify its harmlessness.The disinfection took place in 1977 in Saclay. After the irradiation, the returns to the Cairo museum of the mummy and its sarcophagus were carried out in a sterile bubble. Since then, sterility has been ensured by a plexiglass box equipped with submicron filters to allow ventilation without taking the risk of re-infestation by fungal spores settling on the mummy.
© Arc Nucléart
The simple disinfection, curative treatment, requires a relatively short-term irradiation of objects. The sterilization requires significantly more intense radiations. It is necessary to adjust the dose of radiation to the nature of the parasites that we wish destroy. Thus, disinfection lasts from one to several hours, so that sterilization requires twenty hours. It is necessary, for example, 500 Grays (Gy) to sterilize the wood-eating insects and 2000 Gy to kill the growth of certain fungi, 10 000 Gy or more for a sterilization.
This technique is very suitable to disinfect furniture, statues, ethnographic objects, mummies, etc…. Disinsectization and disinfection by irradiation have been successfully used for forty years by the Arc-Nucleart Grenoble workshop. From private furniture to the prestigious collections of national museums, several thousand cubic meters of objects have undergone these treatments. Among the advantages of this method, there is the fact of a mass treatment without contact, without the use of products of any kind, chemical or other, and therefore without any damage. Treating through the packaging itself avoids repeated direct handling and the risk of damage.