Parameter measurement and optimization for a 3/6 dual-energy electron linear accelerator with industrial and inspection applications

Abstract

Electron linear accelerator (LINAC) is a high-energy X-ray generator with extensive industrial, inspection, and medical applications. The studied LINAC uses a 2.6 MW magnetron as its RF generator derived with a Marx modulator. An electron gun of filament voltage 6 V and current 2.2 A connected to the accelerator tube is applied to establish electron current inside the drift tube. For this purpose, 9 kV and 25 kV voltages are applied to the cathode and anode of the electron gun pulse by pulse, generating dual-energy x-ray beams as outputs. An Automatic Frequency Control (AFC) system is designed for studied LINAC so that variation of output dose rate is lower than 2% and the required time to achieve the maximum output dose rate is lower than 1 s. Optimizing the Marx modulator's switching algorithm, the ripple in the output beam has been lower than 5%. The half-value layer (HVL) of steel has been measured for high and low energies equal to 6 MeV and 3 MeV, respectively. The output pulse of the electron beam and dose rate have been measured using a linear detector array (LDA) and dosimeter, respectively, with a pulse frequency of 35–400 Hz and pulse width of 2–4 μs.