Optimization of Automatic Control and Measurement for the HEPS Large-Scale High-Power RF Conditioning Test

High power radio frequency (RF) conditioning is a key step for the RF components to gain full performance. In the construction of high energy photon source (HEPS), upgrading Beijing Electron-Positron Collider (BEPCII), preresearch of circular electron positron collider (CEPC), and other projects at Institute of High Energy Physics (IHEP), there will be a lot of RF conditioning tasks within a very tight schedule. To improve the conditioning efficiency, an optimized automatic control has been developed. The automatic control system is developed based on the Experimental Physics and Industrial Control System (EPICS). The control hardware platform adopts a combination of the Micro Telecom Computing Architecture (MTCA) based low-level control and programmable logic controller (PLC) interlocking unit, which integrates a variety of measurements to ensure safe and reliable unattended operations during high-power (up to 160 MW) and high gradient (up to 33 MV/m) testing. The finite state transfer based on multiple event-triggered interrupt processes is used to improve conditioning efficiency. Taking the conditioning of the HEPS 3-m-long acceleration structure as an example, the breakdown rate (BDR) at high power is less than one out of 180 000 pulses. The time consumed for each accelerating structure is reduced by a factor of nearly 2/3. Experiments show that the system realizes the unattended operation of whole process, and improves conditioning efficiency.