The beam injection system of the Hefei Advanced Light Source (HALF) utilizes a nonlinear kicker (NLK) based on an 8-conductor geometry. Due to the presence of the internal vacuum chamber and the high sensitivity of the magnetic field distribution to the conductor positions, the design of an 8-conductor NLK demands extreme precision and poses significant technical challenges. To address these issues, an automated design toolchain integrating Opera-2D and Python was developed in this study. A Bayesian optimization algorithm, implemented via the Optuna library, was employed to search for optimal conductor configurations while satisfying stringent constraints on magnetic field quality and spatial positioning. The optimization framework successfully identified a set of feasible design parameters for the HALF NLK within only [40] iterations. Compared with manual iterative methods, this automated approach significantly improves R&D efficiency, providing a generalized tool for 8-conductor NLK design and offering an effective solution for complex optimization problems of non-linear magnets in synchrotron light sources.

Abstract: The Super Taume-Charm Facility (STCF), a new generation of electron-positron collider led by the University of Science and Technology of China, requires a high-quality positron source to sustain high-luminosity continuous operation. The Adiabatic Matching Device (AMD) is a critical component for positron focusing, its excitation pulse source requires a peak current ≥15 kA and a pulse front edge ≤3.5 us. To reduce the significant power dissipation of pulse discharge system, an energy feedback circuit was designed. The optimized system achieved a dramatic reduction in losses, decreasing input power by 73.96% and enhancing long-term operational stability. This article provides a detailed account of the simulation of power loss in AMD excitation pulse sources, as well as the design, simulation, and offline debugging of energy feedback circuits. Key words: excitation pulse power for AMD; power loss; energy feedback; photoconductive semiconductor switch

A pulsed power supply based on a high-voltage op-tically triggered thyristor has been developed for the nonlinear kicker (NLK) magnet of the off-axis injec-tion system at the Hefei Advanced Light Facility (HALF). The NLK requires a short high-current pulse with a waveform close to a half-sinusoidal waveform, fast current rise, and low distortion. An LC resonant topology was adopted and an optically triggered thy-ristor was used as the main switch. A saturable induc-tor was introduced to suppress high-frequency oscilla-tions during the current rise. Experimental results show that the developed system can generate a pulse width below 3.2 μs with a peak current of 5 kA and a current rise rate of about 6.25 kA/μs. The output wave-form is closer to the required half-sinusoidal profile than that obtained with a conventional thyristor-based design, demonstrating the suitability of the proposed power supply for kicker magnet applications in ad-vanced light-source facilities.

This paper presents a highly integrated solid-state modulator designed to drive high-power klystrons in linear accelerators. The modulator employs a vertically integrated architecture in which the solid-state module array is directly combined with the high-voltage pulse transformer. This configuration eliminates long high-voltage cable connections, reduces parasitic inductance, and improves compactness and maintainability. The proposed modulator has been experimentally validated in high-power tests with an 80 MW S-band klystron at the Hefei Advanced Light Facility (HALF), achieving the required pulse waveform quality and stability. In addition, with limited modification, the same architecture can be adapted to higher repetition-rate applications such as the Super Tau-Charm Facility (STCF) injector, demonstrating its scalability for future large-scale accelerator facilities.

An 8-conductor nonlinear kicker (NLK) is proposed for the Hefei Advanced Light Facility (HALF) injection system. Its design is highly sensitive to conductor positions and must accommodate a vacuum chamber. This study develops an automated toolchain combining Opera-2D and Python with Bayesian optimization (Optuna) to search for feasible conductor configurations under strict magnetic and spatial constraints. A feasible design was obtained within 40 iterations, greatly improving R\&D efficiency and offering a generalized approach for nonlinear magnet optimization in fourth-generation light sources.

Abstract: The Super Taume-Charm Facility (STCF), a new generation of electron-positron collider led by the University of Science and Technology of China, requires a high-quality positron source to sustain high-luminosity continuous operation. The Adiabatic Matching Device (AMD) is a critical component for positron focusing, its excitation pulse source requires a peak current ≥15 kA and a pulse front edge ≤3.5 us. To reduce the significant power dissipation of pulse discharge system, an energy feedback circuit was designed. The optimized system achieved a dramatic reduction in losses, decreasing input power by 73.96% and enhancing long-term operational stability. This article provides a detailed account of the simulation of power loss in AMD excitation pulse sources, as well as the design, simulation, and offline debugging of energy feedback circuits. Key words: excitation pulse power for AMD; power loss; energy feedback; photoconductive semiconductor switch

We present a septum magnet based on permanent magnet (PM) for HEFEI ADVANCED LIGHT FACILITY (HALF). Permanent magnet are expected to save more energy and take up less space.