Days ago, IHEP scientists announced that important progress had been made on the digital low level RF (LLRF) control system of the China Spallation Neutron Source (CSNS) Project.

LLRF is a very important system after upgrading the hardware and software of the prototype. To secure the stability of the whole system, IHEP physicists put into a thermostat all the analogous modules, which might be unstable due to temperature changes, such as converter and filter amplifier. In the process of designing the controlling softwares, scientists upgraded the FPGA-based feedback control calculating program, and developed new functions such as automatic frequency conversion and automatic aging of the RF cavity. It is a great leap forward with these improvements; the LLRF will be more stable, more convenient in use and more perfect in functions.

From May 17 to June 20, an on-site test of the LLRF system was held at the IHEP 973-RFQ accelerator. The testing results showed that without beam loading, the amplitude accuracy and phase control accuracy reached ±0.20% and ±0.25°, while under beam loading circumstances, they were ±0.25% and ±0.35°, which approaches the most advanced level of the similar machines.

amplitude accuracy and phase control accuracy in the test