Development of electron beam irradiation station for FLASH experiments at the PBP-CMU Electron Linac Laboratory

Abstract

FLASH radiotherapy (FLASH-RT) delivers ultra-high dose-rate radiation, enabling effective tumor treatment while minimizing damage to surrounding healthy tissue. Implementing this technique requires precise control of electron beam parameters and dose uniformity. This work presents the development of an electron beam irradiation station at the PBP-CMU Electron Linac Laboratory (PCELL), which was structured in four key stages: conceptual design, simulation-based evaluation, physical implementation, and experimental verification. The conceptual design involved the selection of beamline components, diagnostic layout, and irradiation system architecture. Beam dynamics simulations using the ASTRA and Monte Carlo simulations using GEANT4 were performed to optimize beam transport, evaluate interactions with a titanium window, and assess the effectiveness of aluminum flattening filters in achieving uniform dose distributions. Thermal effects from energy deposition in the flattening filter were also analyzed to guide cooling system design. In the implementation stage, the station was constructed with integrated diagnostics, including a dipole magnet and a Faraday cup for energy measurement and a high-resolution current transformer for charge diagnostics. Systematic errors in beam energy measurement were quantified at 3.3%–3.5%, and the CT achieved a bunch charge resolution of 1–2 pC. The experimental verification included calibration of beam diagnostics, beam alignment, and initial system commissioning. While the system demonstrates high precision and dose uniformity, further work is required to evaluate biological effects in FLASH experiments. Future research will focus on real-time dosimetry integration, biological studies, and system automation to further enhance its capabilities.