Electron beam energy measurement in the SLRI 6 MeV Linac using x-ray Scintillator Imaging

The Synchrotron Light Research Institute (SLRI) in Thailand aims to operate a 6 MeV electron linear accelerator for irradiation, supporting various agricultural and industrial applications. This study presents a method for measuring electron beam energy using the existing dipole magnet in the beamline, originally designed for scanning X-rays on samples through a scan horn. An aluminum sheet coated with terbium-doped gadolinium oxysulfide (Gd₂O₂S) was used as a scintillation screen for X-ray illumination and placed downstream of the scan horn. X-ray scintillator images were captured with a CCD camera. By analyzing shifts in the X-ray image centroid as the dipole magnet current varied, we were able to determine the electron beam energy. The experimental setup, simulations, and measurement results are presented and discussed.