Energy Transfer Instruction Manual

Electron Beam Energy Transfer

Absorbed Dose

Absorbed Dose is defined as the amount of energy deposited into a specified mass of material.

The unit of absorbed dose is the kilogray, defined as the number of joules (J) of energy

deposited into 1 kilogram of matter. An older, but frequently used unit, is the megarad (Mrad).

1kGy = 1kJ/kg

1Mrad = 10kGy = 10kJ/kg

At a fixed electron accelerating voltage, the dose is directly proportional to the electron beam

current. Typical values of the dose needed for practical applications are:

Drying/curing of inks and coatings 15-30 kGy

Crosslinking of plastic film 25-150 kGy

Sterilization of medical products 7.5-35 kGy

The transfer of energy from the electron beam into material is specified completely by

four parameters:

Absorbed dose

Depth of penetration

Uniformity

Throughput

PAGE 1
Electron Beam Energy Transfer The transfer of energy from the electron beam into material is specified completely by four parameters: Absorbed dose Depth of penetration Uniformity Throughput Absorbed Dose Absorbed Dose is defined as the amount of energy deposited into a specified mass of material. The unit of absorbed dose is the kilogray, defined as the number of joules (J) of energy deposited into 1 kilogram of matter. An older, but frequently used unit, is the megarad (Mrad).
PAGE 2
Depth of Penetration Penetrating power of the electron beam is related to the accelerating voltage and the density of the processed material. Higher voltage causes deeper penetration, and denser material reduces the depth of penetration. The Depth Dose Curves shown in the figure are convenient aids for estimating the penetration depth.