Industrial / chemical applications of ionising radiation
Radiation dosimetry for high-dose applications is particularly applicable to industry.
Industrial Uses of Radiation
Ionising radiation is used in the radiation processing industry, to produce beneficial physical, chemical or biological effects on an industrial scale. Typical examples are sterilization of medical devices; modification of polymers, curing adhesives and resins; enhancement of gemstones; wire and cable jacket curing; tyre manufacture; and the treatment of waste. Foodstuffs can also be irradiated to extend shelf life or reduce the numbers of harmful bacteria. Illustrated, is the source rack of a commercial gamma irradiator comprising up to several megacuries of cobalt-60, here seen immersed a water storage pond. The blue glow is caused by the Cherenkov radiation emitted by high-energy electrons as they travel through the water.
The biggest industrial use of ionising radiation is in the modification of the properties of polymers. When ionising radiation passes through a material, energy is deposited which can either initiate polymerisation, or cause cross-linking to harden the polymer and increase its melting point.
The other major use of ionising radiation is the sterilization of medical devices. Approximately 50% of the single use medical devices (syringes, scalpels etc) in the UK are sterilized by ionising radiation. By delivering precisely measured doses of radiation, it is possible to ensure that any microorganisms on the devices are destroyed. Because the radiation easily penetrates the plastic or paper packaging, the device can be sterilized after it has been packaged and it will then remain sterile until the package is opened. Accurate measurement of radiation dose is critical to the sterilization process, in order that the radiation dose delivered is sufficiently high to ensure sterilization, but not so high that the medical device or its packaging is itself damaged.
We are able to offer consultation and advice on irradiations of this type, and can perform irradiations using cobalt-60, electron beams or higher-energy photon beams as well as offering calibration services for dosimetry systems (through the mailed alanine dosimeter service), traceable directly to the primary standard of absorbed dose held at NPL. We also offer consultation and advice on calibrations, and we also have significant experience in Monte Carlo modelling of industrial irradiations.
Links
- High dose Cobalt 60 irradiator.
- Electron linear accelerator facility.
- Modelling.
- Chemical dosimetry.
Radiation Hardness Testing
There are many environments where there are elevated levels of radiation, whether the radiation is deliberately or accidentally added, or naturally occurring. These include regions of high natural background radiation such as the Space environment (low or high Earth orbits, and interplanetary), high-flying aircraft, some mines and particular regions on the Earth, as well as circumstances where the radiation is not natural (nuclear reactors, particle accelerators, commercial irradiators, or perhaps the radiation emitted from a nuclear explosion).
NPL's internationally-recognised expertise is available for advice and consultation in all of these areas. In addition, because of the wide range of facilities that we maintain at NPL to carry out our commitments to the National Measurement System, we can often simulate these environments in advance to allow them to be tested. Apart from so-called "in flux" testing, where the operation of components is monitored in a simulation of the environment that they may be used in, we can also often irradiate them at a much higher rate either at NPL or with industry partners, so that their behaviour can be investigated after they have been subjected to the amount of radiation that they would be expected to encounter over their lifetime.