STERIS Applied Sterilization Technologies (AST) offers the industrial products market the most comprehensive array of contract processing options for a wide range of applications for Customers who require a variety of ionizing radiation types.
By offering a complete assessment service based on decades of experience, we are able to advise on the most effective process and what the expected outcome should be.
Cross Linking and Materials Modification for Industrial Products
Make the most of your products with industrial materials modification services from STERIS AST! Materials modification by automated gamma irradiation produces physical and chemical improvements in your bulk polymers.
Modifying the molecular structure of many polymers enhances their physical characteristics, such as resistance to heat and abrasion. STERIS AST employs electron beam and gamma irradiation for initiating these changes at the molecular level in polymers. The absorption of the radiation energy can lead to either cross-linking or chain scission of the macro-molecular chains; electron B-beam accelerators frequently carry this out, although gamma radiation is used in some instances.
The chemical structure and morphology of the polymer plays an important role with regards to its tendency to degrade or to cross-link. For some polymers, the aim is to change thermoplastic materials into thermosets. The molecules in the thermoplastic materials tend to slip and slide over one another fairly freely. As temperatures rise, these uncross-linked materials soften and finally melt. When they are cross-linked, molecular movement is impeded and the material becomes more stable against heat.
The principal types of polymeric product that benefit from treatment by irradiation are:
- Cable jacket materials
- Wire insulation
- Heatshrink and other types of tubing
- Components to be used in high temperature applications, e.g. electrical switch gear parts
- Molded components requiring chemical or temperature resistance
Excellent soft switching characteristics can be achieved by irradiation, reducing or eliminating the use of undesirable heavy metals in fabrication clean rooms and offering an exact process by which to realize different lifetime profiles.
STERIS AST is the only fast-turnaround provider of both electron and ion beam treatments for semiconductors. They are used in combination to optimize switching characteristics.
Treatment with a high-energy electron beam provides bulk control of minority carrier lifetime throughout the entire volume of the device, giving a very even and consistent performance across different production batches. Products can be treated in trays or boxes, preserving the clean conditions in which they were packed. Electron beam treatment provides effective and uniform tailoring of the softness of reverse recovery, while avoiding the increased leakage current associated with other techniques, such as gold or platinum diffusion.
Ion beam treatment, using protons or helium ions, targets the lifetime killing centers to the precise region required, ensuring that localized control is provided. The primary interaction of these ions with the silicon structure has a relatively sharp depth profile, allowing the region for treatment to be defined to a few microns. This enables, for example, the drift region near the PN junction of a diode to be treated to reduce the reverse recovery parameters for soft switching, while leaving the forward voltage drop unchanged. Ion beam treatment is a vacuum process and so wafers are handled individually in our ISO Class 7 cleanroom in order to control particulates. A range of ion species is available, the most commonly used of which are protons and helium ions (alpha particles).
Electron doses typically range from 0.05 to 1,000 kGy (0.005 to 100 Mrad) and proton and helium ion doses from 1E9 to 1E13 ions/cm². Irradiation is carried out with high uniformity and reproducibility and products are handled in an ISO class 7 cleanroom environment. Services are performed in accordance with written procedures within our Quality Management System, which is certified to BS EN ISO 9001.
Ionizing radiation is found across a wide range of applications, from nuclear to space, through to numerous industrial processes. STERIS AST provides a comprehensive selection of radiation testing facilities and services, based upon our unrivaled portfolio of irradiation plants across The Americas, Europe, Africa and Asia.
Expertise in Radiation Effects
- Pre-irradiation assessments
- Electronic circuit simulation
- Materials selection
- Component selection
- Cobalt-60 gamma irradiation facilities
- Electron beam irradiation facilities (1 – 20 MeV)
- Ion beam irradiation facilities (0.5 – 10 MeV protons, 0.5 – 15 MeV alphas, etc.)
- Database of published data on radiation effects
- Shielding/penetration calculations
- Radiation and environmental testing
The assessment of radiation effects on materials and components normally considers several aspects of the radiation environment in turn. STERIS AST offers test facilities for total dose, electrons and protons as follows:
- Total integrated dose: gamma radiation from cobalt-60 sources; dose rates from background to several kGy/hr (depending on sample size); in-situ monitoring, temperature control
- Electron irradiation: from 1 to 20 MeV; doses from tens of Gy to MGy; in-situ monitoring; temperature control; sample handling by conveyor or static positioning under the beam (forced cooling required).
- Proton irradiation: from 0.5 to 10 MeV; irradiation in vacuum or air; in-situ monitoring, temperature control; ISO Class 7 (class 10,000) clean room available.
- Helium ion (alpha) irradiation: from 0.5 to 15 MeV; irradiation in vacuum or air in-situ monitoring, temperature control; ISO Class 7 (class 10,000) clean room available.
The synergistic effect of irradiation and other factors can lead to more rapid degradation than the sum of the individual effects would indicate. We offer the possibility to irradiate in a range of gaseous environments and vacuum, with heating or cooling, with or without electrical stress and, for solar cells, under illumination.
Nuclear Component Processing
STERIS AST provides the nuclear services industry with radiation exposure for nuclear components. Our services are utilized to expose nuclear components and materials to gamma radiation for both lifetime and accidental radiation exposure.
Space Environment Testing
The space radiation environment is a complex and varying phenomenon, dependent upon many factors, including orbit, time of year and solar activity. The ability of electronic components and materials to survive the hostile radiation environment in space is of critical importance for satellite missions. The accurate assessment of degradation due to radiation effects prior to deployment is essential. A thorough understanding of the mission requirements and the likely effects of radiation on satellite components help ensure maximum operational reliability.
STERIS AST can provide a range of testing services to assess the resistance of components, materials and systems to electron and proton irradiation in the critical energy range of 1 to 10 MeV. Samples are exposed to uniform and highly controlled radiation doses in various environmental conditions (temperature, atmosphere, pressure, illumination, vacuum). The simultaneous measurement of electrical parameters is also possible.
Many types of gemstone can benefit from enhancement of their color through treatment using exposure to ionizing irradiation. STERIS AST offers a high quality, fast turnaround electron treatment service for gemstone enhancement built on technical expertise and nearly 20 years of experience.
Our facilities at Daventry (UK), Radeberg (Germany) and Chonburi (Thailand) are optimally configured for efficient gemstone enhancement treatment allowing high dose and high energy electron processing of rough, pre-form or cut stones in approximately 1kg lots.
Why STERIS AST?
As a global leading sterilization and contamination control specialist, STERIS AST has over 40 years experience in providing safe and effective industrial application processing.