In the beam diagnostics system of the CSNS accelerator, multiple National Instruments (NI) PXIe multifunction DAQ modules were utilized for readout system development. The original software architecture, implemented with LabVIEW+DSC modules on Windows system, introduced substantial challenges in EPICS integration. This paper details a software upgrade methodology that preserves the existing NI PXIe hardware infrastructure. The upgraded system implements standard EPICS Input/Output Controllers (IOCs) developed in C language under Linux system, integrating signal acquisition and front-end electronics control functionalities within EPICS IOCs. This re-engineering approach enhances the readout system stability while improving the reliability and flexibility of EPICS data interaction. The successful migration demonstrates an effective hardware-preserving software optimization strategy for accelerator instrumentation systems.

China Spallation Neutron Source (CSNS) accelerator complex will employ a new superconducting accelerating section to achieve high beam power. To protect the superconducting cavity from contamination, the second phase of the CSNS superconducting linac section will adopt laser stripping technology for transverse distribution measurements of the negative hydrogen beam at nine stations. In 2024, a laser wire(LW) prototype was installed to measure the profile of the 80MeV H- beam. This paper describes the commissioning results of this LW prototype, including the optimization before scanning, and data analysis.

A laser wire monitor has bean developed at the China Spallation Neutron Source (CSNS).The monitor utilizes a 1064 nm laser source to measure the horizontal and vertical profiles of a negative hydrogen ion (H-) beam with an energy of 80 MeV in the injection zone. This paper describes the design of the laser optical path layout and the characterization of the transport performance. The experiment focuses on the laser system's quality factor M2 of the laser after more than 60 meters of transmission as well as the beam pointing stability. In this experiment, the laser quality factor M2 after transmission is better than 4, and the beam pointing stability after focusing is less than ± 2.5 um, which is able to satisfy the required specifications for the first laser wire monitor of the CSNS.

To enhance the performance of next-generation X-ray Free Electron Lasers (XFELs), it is crucial to produce high-quality electron beams with low emittance, particularly for attaining emittances below 0.2 mm.mrad for 100 pC bunch charges. This study introduces an emittance measurement method using an orthogonal dual-slit technique, aimed at enhancing measurement efficiency and achieving the necessary measurement accuracy for such small emittances. An emittance meter based on this method has been designed for a C-band photocathode RF gun at the CSNS campus. Finally, we present numerical simulations to optimize the primary parameters of the emittance meter, focusing on beam drift distance, combined with the motion accuracy of the stepper motor and the expected resolution of the optical observation system to ensure the accuracy of the emittance measurement.

The CSNS RCS (Rapid Cycling Synchrotron) is a proton accelerator designed to achieve a target beam energy of 1.6 GeV, with a typical operating intensity of 140 kW, which is expected to increase to 500 kW after the CSNS II upgrade. However, a significant current instability has been observed during the 100 kW beam operation. To mitigate this instability, techniques such as operational tuning and chrominance modulation were previously used to make the 100 kW beam operate stably. In order to face the subsequent stronger instability, a bunch-by-bunch transverse feedback system is required to mitigate the coherent lateral oscillations caused by instability and injection errors. In this paper, the preliminary design of the feedback system will be presented.

In the China Spallation Neutron Source (CSNS), an Ion Profile Monitor (IPM) was installed in the Rapid Cycling Synchrotron (RCS) to address challenges in measuring strong-current beam profiles and enable real-time monitoring. This study focuses on the preliminary analysis of IPM data signals, aiming to accurately extract critical beam information from the signals. Residual gas components in the vacuum chamber were identified through peak spacing calculations. Real-time beam profiles (0–20 ms, low power) were obtained, revealing the beam center and temporal evolution of rms beam size. Fast Fourier Transform (FFT) of signal peaks uncovered dynamic changes in the synchrotron tune. Single- and multi-Gaussian fitting methods were used to analyze MCP-collected charge over time and determine MCP saturation time point. The results demonstrate that IPM data analysis effectively extracts beam information, supporting real-time monitoring and optimization of CSNS RCS beam stability and quality.

As part of the CSNS-II upgrade, an improved injection scheme will be implemented to mitigate the space charge effect. To precisely measure the transverse beam position during injection, painting, and storage in the Rapid Cycling Synchrotron (RCS), a large-aperture (260 mm × 180 mm) Beam Position Monitor (BPM) is essential. The rectangular cut-plane BPM was selected for its excellent linearity over a large area and high signal-to-noise ratio (SNR). Due to limited space in the injection section, the BPMs must be integrated into the AC steering magnet. To prevent thermal heating from eddy current flow, a rib structure has been incorporated into the BPM's outer body. The BPM was designed using numerical simulation codes and subsequently manufactured. This paper details the simulation, design, and calibration results of the diagonal cut-plane BPM.