NSLS-II is a 3 GeV third generation synchrotron light source at BNL. The storage ring was commissioned in 2014 and began its routine operations in the December of the same year. Since then, we have progressed steadily upwards in beam current and reached 500 mA in five years while continue to install and commission new insertion devices. Along this path, we met various challenges. In this paper, we report our experience and the improvements to reach high current.

The Radio Frequency System-on-Chip (RFSoC) FPGA-based high-performance bunch-by-bunch beam position monitor (BxB BPM) was developed and commissioned at NSLS-II. The new BxB BPM features a 14-bit 5 Gsps ADC, directly sampling 2 ns four-button signals, and digital signal processing with a synchronized 500 MHz RF reference clock. The BxB BPM provides 32 K points of ADC raw data, 5 K turns for up to 1320 bunch amplitude and position data, 2.6 million turn-by-turn (TxT) data points, 10 K turns of circular buffer, and 10 Hz streaming data. The potential applications include, but are not limited to measuring injection transient, efficiency, ion instability detection, and single/multi-bunch motion analysis. A ~15 μm single-bunch resolution was confirmed with the beam test. This paper will present the beam test results, hardware FPGA firmware architecture, and control system interface for operation.