Electron energy device for process control

Abstract The electron energy is one of the principal parameters that influence the dose distribution within a product treated with a beam of energetic electrons. An easy-to-use and robust device has been developed that can reliably detect day-to-day small variations in the beam energy. It consists of two identical aluminium plates except for their thickness, which are electrically insulated from each other. The thickness of each plate is carefully selected depending on the electron-beam energy. The charge (or current) collected by each plate, while under the beam, is measured by an electrometer. The ratio of the charge (or current) signal from the front plate to the sum of the signals from the front and rear plates is very sensitive to the beam energy. We have used this device with an accelerator with maximum beam energy of 12 MeV. The high sensitivity and robustness make this device quite suitable for process control applications at an e-beam radiation-processing facility.