3.5-cell large grain niobium superconducting cavity for a dc superconducting rf photoinjector

• Main Authors: Shengwen Quan, Feng Zhu, Jiankui Hao, Xiangyang Lu, Baocheng Zhang, Wencan Xu, Kui Zhao
• Format: Article
• Language: English
• Published: American Physical Society 2010-04-01
• Series: Physical Review Special Topics. Accelerators and Beams
• Online Access: http://doi.org/10.1103/PhysRevSTAB.13.042001

We have developed a new compact high average current dc superconducting rf (DC-SRF) photoinjector. A 3.5-cell superconducting cavity with a mid-beta structure is the key component of the DC-SRF photoinjector. Herein, we present the new design, fabrication, and vertical test results of the 3.5-cell large grain niobium superconducting cavity. After preliminary surface preparation and room temperature rf measurements, the cavity was sent to Jefferson Lab for a vertical cold test. The gradient of the cavity reaches 23.5  MV/m, and the Q_{0} value is higher than 1.2×10^{10}. The high-quality 3.5-cell cavity will guarantee the good performance of the DC-SRF photoinjector.