CSNS/RCS low level RF digital controller

1Background

Background

· The project is in the demand of the Institute of High Energy Physics, Chinese Academy of Science for Fast Cycling Synchrotron (RCS) low level RF digital controller in one of the national major science and technology infrastructure projects, namely China Spallation Neutron Source (CSNS).
· CSNS as a key scientific device during the Eleventh Five-Year period is located in Dongguan City, Guangdong Province. Its construction is in the charge of both Chinese Academy of Sciences and Guangdong Province, with total investment of the project expected to be ¥2.2 billion.
· Institute of High Energy Physics, Chinese Academy of Sciences is the corporate entity of CSNS and the Spallation Neutron Source National Laboratory in Dongguan, Guangdong.
· After being completed, the CSNS will be one of the world's four major scientific centers of pulsed spallation neutron source, while the others are respectively located in UN, America and Japan, and it is also the first spallation neutron source in developing countries. Every year, it will accommodate thousands of researchers working on different spectrometers.

2Requirements

CSNS/RCS low level RF control system is a complex multi-loop control system, with CSNS/RCS RF low-level digital controller as the core component of the low level RF control system. The digital controller using embedded digital and modular CPCI bus structure achieves all control functions based on FPGA and DSP chips on the board. The required functions include signal acquisition related to various control loops, data processing and computing, amplitude control of RF acceleration voltage, dynamic tuning of the cavity, synchronization of cavity voltage with the beam phase, RF frequency correction, feedforward and feedback of beam loading, etc. In addition, the stability and reliability of the system to continuously work long hours are highly required.

3Achievements

LINCOLN based on advanced technology of the overall balance design, with comprehensive consideration of the performance, reliability, compatibility, cost, size, weight and power dissipation, achieved optimal match of users’ requirements with the design of CSNS/RCS low level RF digital controller system. This solution can not only satisfy the requirements for high-speed AD acquisition, high-speed DA playback, high-performance signal processing, and extremely high transmission bandwidth, but also acquire excellent specifications in terms of performance, cost, reliability, power consumption and so on.

The main features of the solution include:
1. Optimized design is adopted to meet the needs of long-term stable operation, which includes using ADC interface IP core with intellectual property rights (authorized patents) to effectively improve the stability and uniformity of ADC acquisition module, using DSP interface conversion technology to effectively improve communication stability between FPGA and DSP and utilizing multi-level dynamic power management technology to achieve multi-level power management of system, hardware boards, components, power design, the underlying software, etc., to ensure the stability of the digital controller to work for long in narrow cooling space;
2. Use a new generation of mainstream DSP processing board and provide DSP integrated development environment with completely independent intellectual property;
3. Use independent health monitoring and management system, provide health monitoring and management system software and offer technical support for fault location and problem reappearance in system debugging and test;
4. Adopt strict design and safeguards of high reliability, conduct strict tests for CSNS / RCS low-level RF digital controller based on testing and validation environment under years' construction with complete FPGA logic, software code and sound hardware performance and improve the stability and reliability of the whole system for users.

Achievements