Gamma irradiation, application

Kamat, A. et al.. Potential application of low dose gamma irradiation to improve the microbiological safety of fresh coriander leaves. Food Control, 14, 529, 2003. 

The fission product and encapsulation plant (FPCE) to be built by Isochem, Inc.y in Washington state will produce fully encapsulated fission products for the commercial market. Among these, all of which are extractable from Hanford s plutonium process residues, is cesium-137, a 600-kv. gamma emitter of interest to the process irradiation industry. Isochem will offer cesium in large production quantities and low cost to irradiators of foods, woods, chemicals, etc. Its 30-year half-life promises economies in source array replenishment to compensate for decay. Cesium thus becomes an economic contender for current and planned irradiation applications. 

Stability to gamma irradiation has been investigated by researchers at Lock-heed-Martin Corporation, the Air Force Research Laboratory (Dayton, OH), and by ourselves. The results (no detectable change in performance) suggest that polymer modulators are suitable for space applications. We have, by electron... 

For technical applications, knowledge of the irradiation behaviour of the Levextrel-TBP resin is important. A detailed study carried out at the Radiochemistry Institute of the Technical University, Munich(21,22), showed that with gamma irradiation the formation rate of dibutyl phosphoric acid (HDBP) and of "non-removable" acidic radiolysis products ("do-bads") is 2 to 5 times lower with Levextrel-TBP resin than with pure TBP the effect is attributed to the "scavanger" action of the aromatic groups in the matrix material. In summary, a high radiation resistance of the resin has become evident. 

Wooten, M. (1985) Application of gamma irradiation to cereals and cereal products. In Regional Workshop on Commercialisation of Ionising Energy Treatment of Food, Lucas Heights, 1985, Lecture 14. Australian Atomic Energy Commission, Lucas Heights, New South Wales. 

A variety of techniques have been applied for sterilizing microfluidic cell culture chips and covered by reviews [12, 25] and references therein, such as autoclaving, UV light, oxygen plasma, gamma irradiation, ethylene oxide exposure and perfusion with ethanol, hypochlorite or sodium hydroxide. The applicability of the different techniques primarily depends, aside from what is available in a laboratory, on the type of system and the fabrication material. Autoclaving is an effective method but not suitable for chips fabricated of thermoplastic polymers. The applied temperature and pressure... 

Thicker grades can be thermoformed (medical and pharmaceutical applications) and subsequently sterilised by steam autoclaving, gamma irradiation, etc. Non-oriented PET has a high melting point, around 250°C. 

Although certain products can be terminally sterilised by moist heat, gamma irradiation or accelerated electrons, these tend to apply to relatively few pharmaceutical applications where flexibles are involved (the last two are more widely used for medical instruments in pouches or sachets). 

Hauser et al. [1993] claim that articles for medical and other uses made from a polymer alloy of a clear styrenic acrylate, a ductile styrene-diene polymer, and a rubbery block styrene-diene copolymer may be sterihzed by gamma irradiation, without significant increase in its yellowness index or significant deterioration of the alloy s mechanical properties (Table 11.9). There are many applications, e.g., urine sample botdes, items in space probes, and cosmetic containers, that are made from transparent plastics and need to be radiation-sterihzed. However, many clear plastics do develop color on irradiation, and their mechanical properties tend to deteriorate, particularly on irradiation in air. Hauser et al. 

Realization of cold cracking of hydrocarbons requires application of high dose rates that cannot be reached when using gamma-irradiation sources. For this reason, electron irradiation is more appropriate for this type of oil processing. Modern electron accelerators provide the dose rates of tens and hundreds kGy per second sufficient for intense reactions of cold cracking. 

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