The RFQ cavity for Injector I of the ADS Proton Linear Project has been repaired, and started continuous conditioning again on July 6th.
During its first conditioning, which started on May 14th, the RFQ cavity broke down due to damage to the middle and end coupling plates. ADS members immediately discussed and analyzed the problem, and proposed a solution, which was supported and executed by staff from the IHEP Machine shop and Division of Equipment Operation and Maintenance. The coupling plates were restored completely in only 12 days, which is much shorter than the usual manufacturing period, ensuring the timely conditioning of the next round.
Since the Labor Day holiday (May 1st), all ADS group members worked overtime, some even giving up their vacation and working into the small hours, in order to complete the RFQ conditioning on time. All the preparation work, including connection of the water-cooling pipes, connecting the controlling wires with temperature probes and water flow, as well as cavity alignment, were completed in only 13 days. Meanwhile, an on-duty group of 20 people from the RFQ, Coupler, High Power and Power Supply Systems groups of the ADS Project was established, and started working in shifts to run the conditioning 24-hours. .
This RFQ cavity, developed by IHEP, is critical for the ADS linac. With a total length of 4.7m, it is designed to consist of four cavities working at a radio frequency of 325MHz, and to be capable of providing 35kV-3.2MeV acceleration under constant wave operation mode. The general installation of the ECR, RFQ, couplers and the movable measurement platform located in the tunnel of No.1 Experimental Hall was finally completed in mid-May.
The conditioning work on the ADS Injector I RFQ is still pushing forward firmly in spite of difficulties. The current duty cycle has already been conditioned to the level of 90%, and average input power has reached as high as 230kW.
The RFQ cavity for Injector I of the ADS Proton Linear Project （Image by IHEP）