On March 4, the China Spallation Neutron Source (CSNS) at the Institute of High Energy Physics of the Chinese Academy of Sciences, successfully reached a target beam power of 185 kW and achieved stable beam delivery operation, marking a key step in improving the performance of the CSNS facility and an important milestone in the construction of CSNS-II.

The task to increase the beam power to 185 kW officially began on February 4, 2026, which has faced unprecedented physical and technical challenges.

Following the comprehensive upgrade of the full-energy injection system in 2025, the beam dynamics of the Rapid Cycling Synchrotron (RCS) changed significantly. In addition, several critical hardware systems such as the ring RF system and power supplies were upgraded, while limitations in the linear accelerator hardware performance and issues such as energy jitter further increased the complexity of beam physics simulations. As a result, certain deviations between simulation results and actual measurements became the core obstacle to increase the power.

The achievement of stable 185 kW beam supply has once again set a new record for CSNS beam power, following successive breakthroughs of 160 kW and 170 kW in 2024, marking an important milestone in the performance improvement of CSNS.

The substantial increase in beam power will further shorten user experiment time, improve the efficiency of the facility, and provide stronger technical support for cutting-edge scientific research in new energy, advanced materials, aerospace, chip development and other fields. Meanwhile, it has fully verified the key technical route for beam power upgrade in CSNS-II and accumulated more beam commissioning experience after the upgrade of complex hardware systems at high power, laying a solid foundation for the subsequent hardware upgrade, the continuous power improvement and the construction of CSNS-II.

Fig:24-Hour Accelerator Beam-on-Target Power