Characterization of a Radiation Source for a Container Inspection System Based on a Dual-Energy RF Linac

Abstract

A container inspection system (CIS) is a piece of that uses X-rays to scan inside a cargo container without opening it. These X-rays are generated by Bremsstrahlung which occurs when an electron beam accelerated by using a radio frequency (RF) linear accelerator (linac) hits a metal target. The RF linear accelerator is fed 2856 MHz RF power from a magnetron and accelerates the electron beam so that it attains energies up to 6 and 9 MeV. The linac is designed as standing-wave type linac, and RF power is transferred between cavity cells through side-coupling cells inside the linac. Bremsstrahlung radiation generated at the target penetrates the cargo container, and transmitted X-rays are detected by using detection modules. Detected X-ray signals are post-processed by using imaging software, and finalized images are obtained. The linac cavity was designed and fabricated by the Korea Atomic Energy Research Institute (KAERI), and dual-energy X-rays were successfully generated after RF conditioning. Finally we could obtain scanning images that could be used to distinguish organic from non-organic materials. Diagnostics have been conducted to characterize the electron beam and the X-rays to verify CIS performance and improve the scanning image. In this paper, we discuss the configuration of and performance test results for the X-ray generating linac developed by the KAERI.