There are two fundamental properties of all electron beam accelerators: the electron energy and the beam current. Since electrons have mass and electrical charge, their penetration into materials is limited by their energy and by the mass and density of the target material.
The intensity or degree of exposure to electrons is called the absorbed dose, which is characterized in the System International (SI) as the gray or as commonly used in industrial processing, the kilogray (kGy) where 1 kGy = 1 J/g absorbed energy per mass.
Over the decades of industrial use, key market segments such as Surface Curing, Shrink Film, Wire & Cable and Sterilization have found reliable industrial accelerators suited for their requirements.
Given an overlap of tail ends of the depth-dose penetration, two sided electron beam exposure results in an effective 2.4 multiple of the Electron Beam penetration itself. Thus, fairly large, low bulk density packages can be irradiated if the item is turned over during processing.
High beam current is what distinguishes industrial electron beam accelerators from equipment that is commonly used solely for research purposes. Most industrial accelerators have beam currents in the tens of milliampere range (>10 mA). High beam currents are required in industry because product through-put rates are proportional to beam current.
Since material through-put is dependent upon beam current and beam power, one can see why industry prefers to use high beam current and high power accelerators. High beam currents also imply very high dose rates. Industrial electron beam dose rates are in the order of 100 kGy/second or 360,000 kGy/hour. This is five orders of magnitude greater than the dose rates from cobalt-60 gamma-ray sources, which are ~10 kGy/hour or 2.8 × 10-3 kGy/second.
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