Low Level RF Workshop 2013

The Improvements of LLRF Control System for CSNS Linac

Not scheduled

Poster

Speakers

Ms Linyan Rong (Institute of High Energy Physics, Beijing, China)Mr Zhencheng Mu (Institute of High Energy Physics, Beijing, China)

Description

In the finished ADS (Accelerator Driven Sub-critical system) project which supported by China 973 Program in the Institute of High Energy Physics, Chinese Academy of Sciences (IHEP, CAS), a 352.2MHz klystron RF power source was used to drive 3.5MeV RFQ accelerator. On this test stand, we carried out R & D of digital low level RF (LLRF) control system prototype for CSNS LINAC RF system. Based on step-by-step successful R & D and operation experience, many important progresses have been achieved. In design of the process, all analog modules were thermostatically controlled by a temperature stabilizing crate, the related circuits of both cavity field signal and reference signal were designed symmetrically. In design of the control software, the FPGA-based feedback control algorithm has been optimized, and some useful functions were added, such as 1) measuring of cavity Q value, detuning phase and frequency shift, 2) automatic frequency matching for cavity warm-up, 3) using feedforward to compensate the amplitude and phase decrease caused by klystron high voltage droop, 4) RF power monitoring and real-time VSWR protection. The improvements and test results of the LLRF control system for CSNS LINAC will be described here.