Proton accelerator high performance dual Spoke superconducting cavity successfully developed

[ Instrument Network Instrument R & D ] Engineering and technical staff of the RF Superconducting and Cryogenic Research Center (Accelerator Center) of the Institute of High Energy Physics and Beijing Gaonengrui New Technology Co., Ltd. have jointly developed CiADS proton accelerator and China after more than two years One of the core equipments of the second phase of the spallation neutron source upgrade project, the dual Spoke superconducting cavity, has captured and mastered the core technologies including the superconducting cavity physical design, processing technology, surface treatment and testing technology. At the end of December 2019, the development of a 325 MHz dual Spoke superconducting cavity sample cavity was successfully completed.

325 MHz dual Spoke superconducting cavity vertical test results

The 325 MHz dual Spoke superconducting cavity has an accelerated gradient Eacc of 14.8 MV / m under the 2K vertical test, corresponding to Q0 of 1.16 × 1010, and the corresponding peak magnetic field is as high as 129mT. This result is already the performance of the current international dual Spoke superconducting cavity High level. The results of this vertical survey show that in the current preliminary design scheme of the Chinese spalled neutron source phase II project, the design operating gradient of the dual Spoke cavity is 7.3MV / m, and Q0 is 2.3 × 1010 without this gradient. Obvious radiation dose, fully meet the needs of the spalling phase II project.

Double Spoke superconducting cavity

In order to reduce Ep / Eacc, the dual Spoke superconducting cavity is optimized during design, which can minimize the risk of field emission during operation; in addition, researchers have set a large diameter of 100mm on the cavity The cleaning port uses an innovative coupling coupling design to ensure sufficient post-weld surface treatment and high-pressure water cleaning, and to avoid the field emission electrons of the ceramic window of the coupler during the superconducting cavity level test and operation. Deposition breaks down and breaks. It is worth mentioning that the cavity's quality factor is effectively improved after using the barrel polishing process, which is also the first time in the world to apply the roll polishing process to a half-wavelength superconducting cavity.

The successful development of the dual Spoke superconducting cavity is another important progress in the research and development of the proton superconducting accelerating cavity. It has laid a very important foundation for the CiADS project and the second phase upgrade project of China's spalled neutron source.