Beta & gamma rays
Functionality and advantages
IONIZING RADIATION : RADIATION WITHOUT RESIDUE
From a radiation source, radiation transmits energy, either as electromagnetic waves (as in gamma radiation) or as a stream of particles (as in beta radiation). This high-energy, ionizing radiation triggers chemical reactions, renders microorganisms harmless and improves the properties of a wide range of products. At BGS, we use both beta radiation, also known as electron radiation or E-Beam, and gamma radiation for radiation sterilization and radiation crosslinking. Due to physical limitations, the ionizing radiation does not induce any secondary material activation. The treated products are also completely free of residues and can be used immediately.
BETA & GAMMA Rays: TECHNOLOGICAL DIFFERENCES
Parameters | Beta rays / E-Beam | Gamma rays |
|---|---|---|
Dose rate | High | Low |
Penetration depth | Medium | Very high |
Irradiation time | A few seconds | Several hours |
Energy source | Electric current | Cobalt-60 |
Irradiation unit | Single cartons, multiple cartons or endless strand | Paletts |
Plastic compatibility | Very high | High |
Procedure description | Electrons are emitted in a hot cathode and accelerated to a very high speed in a high vacuum by a strong electric field. As it leaves the accelerator, the electron beam is guided across the product in lines at high frequency by a magnetic field. | Gamma rays are produced through the decay of a radioactive isotope, e.g. cobalt-60. The rays have a high penetration depth and penetrate entire pallets or containers. Cobalt-60 is arranged in individual sources and installed in the source rack, creating an individual radiation field. The products are transported through this radiation field via a predetermined path. The required radiation dose is applied to the product. |
OVERVIEW BETA Rays
Radiant energy
- Beta rays
- Products are exposed to high-energy electrons
Technical parameters
- Radiation energy
- Dose adjustment
- Various handling systems
Product factors
- Suitable for the irradiation of products with low to medium density
- Compatible with a wide range of plastics
STERILIZATION & MATERIAL REFINEMENT : SECONDARY TREATMENT WITH FAST RADIATION
Beta rays (E-beam) are characterized by their low penetration depth at high dose rates. Individual packages can be treated with beta rays within a few seconds – under optimal conditions, a complete truckload can be treated within a few hours. The advantage: products can be processed without delay, i.e. without storage and the associated costs. The low penetration depth of the beta rays makes it necessary to unload the packaged products to the transport pallets, process them and stack them back again. At our site in Saal, a fully automated system processes large quantities of products in a very short time.
Accelerated electrons are generated by electron accelerators, which are comparable to a Braun tube: A hot cathode emits electrons, which are accelerated in a strong electric field in a high vacuum. If energies above 5 MeV are required, BGS uses resonance accelerators of the Rhodotron® type. In these, electrons are accelerated in a cyclic alternating field in several stages up to a maximum energy of 10 MeV. The electron beam emerging from the accelerator is deflected in an alternating magnetic field so that it hits the products to be irradiated in a fanned-out manner. These are passed under the beam using a suitable transport system.
The process characteristics of beta irradiation differ fundamentally from irradiation with gamma rays. The products are usually fed through the irradiation process in the transport packaging as individual cartons, loose bulk goods or unwound as a continuous strand and then wound up again. This only takes a few seconds. The possible fill level of the irradiation unit depends on its density, its packaging scheme and the energy of the electrons.
Beta rays / E-Beam treatment is best suited for
- the sterilization of uniformly packaged products with a low density (e.g. medical products in small packaging units),
- the sterilization of uniformly packaged products with low density,
- the modification of polymers,
- the refinement or crosslinking of plastics,
- the refinement of semiconductors.
VIDEO: PRINCIPLE OF electron radiation
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More InformationOVERVIEW GAMMA RADIATION
Radiation energy
- Decay of cobalt-60
- Products are exposed to gamma radiation
Technical parameters
- Dwell time in the system
- Equipping the source rack
Product factors
- Suitable for the irradiation of low, medium and high density products
- Compatible with a wide range of materials
STERILIZATION & MATERIAL REFINEMENT : MAXIMUM PENETRATION WITH GAMMA RADIATION
In contrast to electron accelerators, where the irradiation process takes just a few seconds, irradiation in the gamma facility takes several hours. The gamma rays are formed by the decay of the radioactive isotope cobalt-60 (60Co). They have a high penetration depth at a low dose rate and therefore have the ability to penetrate complete pallets, containers and sealed products. The products to be irradiated can usually run through the irradiation process directly on the delivery pallets. The pallets enter the system via a conveyor system and pass around the source rack equipped with the individual source pencils. The control system ensures that each pallet completes the specified number of loops. This ensures the specified irradiation dose in total for each product. The gamma systems at BGS can irradiate different products with different final doses at the same time.
To ensure safe access to the irradiation system, the source rack is lowered into a water basin over eight meters deep to completely shield the radiation.
Gamma ray treatment is best suited for:
- the sterilization of single-use medical devices,
- the sterilization of packaged products with low to high density,
- products with complex geometries (e.g. components or bioreactors),
- the sterilization of raw materials.
VIDEO: PRINCIPLE OF GAMMA RADIATION
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BETA & GAMMA RAYS : RADIATION STERILIZATION
Both beta and gamma radiation are suitable for sterilization. Parameters such as the structure, density and material of the product determine which method is more suitable. The high-energy beta or gamma rays destroy the DNA of microorganisms, rendering them harmless. Sterilization with radiation is therefore the only process to sterilize products in their packaging without significantly increasing the temperature and without using chemicals, which always carry the risk of residues. Even the inner surfaces of closed packaging or components with complex geometric shapes are sterilized by high-energy radiation safely and reliably. These advantages make radiation sterilization a simple, effective and environmentally friendly alternative to other methods.
BETA & GAMMA rays : RADIATION CROSSLINKING
Beta rays as well as gamma rays are also used for the refinement of products. As higher irradiation doses are required for the crosslinking of plastics (50 to 250 kGy), the high dose rates of electron accelerators are predominantly used to introduce the required dose in economical irradiation times. In the case of radiation-sensitive materials, the irradiation time can also have a negative influence on the properties depending on the dose rate – another reason for using electron beams with a high dose rate and therefore short irradiation times. In the case of compact components with higher wallthicknesses gamma irradiation can also be used for crosslinking due to the greater penetration depth required.
Technical Brochures
Our technical brochures radiation sterilization & radiation crosslinking answer key questions on technology, procedures and process integration.
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FAQ: PRODUCT RADIATION: FREQUENTLY ASKED QUESTIONS
No! For physical reasons, the radiation can only trigger chemical reactions in the products. The energies used in the BGS systems are too low to generate radioactivity in the products.
Depending on the radiation dose applied, there is no significant heating of the products during irradiation. At higher doses, which are normally necessary for crosslinking, there is a slight increase in temperature.
The energy of the rays is expressed in mega electron volt (MeV), which describes the strength of the electric field used to accelerate the electrons. It is directly related to the penetration depth of the beams. It is limited by the design of our equipment to a maximum of 10 MeV to prevent activation of the products. The dose (or amount) of radiation is expressed in Gray (Gy), which determines the desired effect of the irradiation. For radiation sterilization the dose range of 25 kGy is often sufficient, while for radiation crosslinking doses of over 100 kGy are typical.
No, depending on the material density and the energy of the beta rays (E-Beam), the penetration depth of the rays can be up to several centimeters. This enables reliable modification of components with a considerable material thickness, which may also contain metal components.
BGS has developed equipment and maintenance systems that ensure high reliability. In most cases, redundant production facilities are available to ensure continuous high availability of production capacity and guarantee reproducibility.
FURTHER INFORMATION : FUNCTIONALITY
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