The novel and robust design of fast protection system for CSNS-II

The high reliability of the fast protection system(FPS) is crucial for the efficient operation of the entire large-scale scientific facility of Chinese Spallation Neutron Source(CSNS). The construction of the CSNS-II began nearly two years ago. In this new phase, an advanced linear superconducting section is scheduled to be introduced. To prevent operational accidents, such as "temperature rise loss caused by beam loss in the superconducting section," it is necessary to enhance the existing fast protection mechanisms. Based on the characteristics of the interlocking requirement, we plan to implement a hardware architecture comprising "high-performance FPGA + Rocket IO + ATCA." While maintaining the core function of the FPS for CSNS, we will develop the transmission link and protection strategy by integrating the beam loss monitor (BLM) and differential beam current monitor (D-BCM). The whole response time of the FPS for CSNS-II should not exceed 8 microseconds, accounting for the fiber optic transmission delay, hardware circuit delay, interlocking logic processing, and so on. It is worth to focus on that a highly available, reliable, efficient, and fast protection should be to ensure the CSNS II accelerator operates stably and safely in the long term.