Toward safe operation of modern synchrotron radiation sources: Computational tools, shielding strategies, and activation phenomena

This paper presents a comprehensive review of radiation protection methodologies and representative practices in synchrotron radiation facilities, encompassing both established third-generation light sources and emerging fourth-generation diffraction-limited storage rings. The fundamental radiation sources in these facilities, including prompt radiation from beam losses, bremsstrahlung, synchrotron radiation, and secondary particle production, are first summarized to establish the underlying physical mechanisms. Radiation protection challenges specific to 4GLSs, such as heightened sensitivity to localized beam losses, narrow-aperture vacuum chambers, and high–power-density insertion devices, are then systematically discussed. The principles and assessment methodologies of radiation shielding design for storage rings, injectors, and beamlines are reviewed, with emphasis on recent advances in loss modeling, source term characterization, and Monte Carlo–based simulation techniques. Representative mitigation strategies and operational experiences from existing facilities are presented to illustrate practical implementation. Induced radioactivity is also examined in detail, addressing the activation of accelerator components, structural materials, air, and cooling water. Activation mechanisms, dominant radionuclides, dose implications for occupational workers and the public, as well as clearance and waste management considerations during maintenance and decommissioning are summarized based on both experimental measurements and computational studies. In addition, this review highlights recent methodological developments and emerging applications in radiation protection, including refined beam loss scenarios, high-precision transport simulations, and integrated safety assessment frameworks. Overall, the paper provides a systematic overview of radiation protection issues and evolving solutions for synchrotron radiation facilities, offering practical guidance for the design, operation, upgrade, and decommissioning of current and future light sources.