The design, construction, and commissioning of a conduction-cooled Nb3Sn demonstration superconducting radio frequency (SRF) electron accelerator at the Institute of Modern Physics of the Chinese Academy of Sciences (IMP, CAS) will be presented. In the context of engineering application planning for Nb3Sn thin-film SRF cavities within the CiADS project, a 650MHz 5-cell elliptical cavity was coated using the vapor diffusion method for electron beam acceleration. Through high-precision collaborative control of 10 GM cryocooler, slow cooldown of the cavity crossing 18K is achieved accompanied by obviously characteristic magnetic flux expulsion. The horizontal test results of the liquid helium-free (LHe-free) cryomodule show that the cavity can operate steadily at Epk=6.02MV/m in continuous wave (CW) mode, and at Epk=14.90MV/m in 40% duty cycle pulse mode. The beam acceleration experiment indicates that the maximum average current of the electron beam in the macropulse after acceleration exceeds 200mA, with a maximum energy gain of 4.6MeV. The results provide a principle validation for the engineering application of Nb3Sn thin-film SRF cavities, highlighting the promising industrial application prospects of a small-scale compact Nb3Sn SRF accelerator driven by commercial cryocoolers.
@article{arxiv.2404.09187,
title = {Stable Acceleration of a LHe-Free Nb3Sn demo SRF e-linac Based on Conduction Cooling},
author = {Ziqin Yang and Yuan He and Tiancai Jiang and Feng Bai and Fengfeng Wang and Weilong Chen and Guangze Jiang and Yimeng Chu and Hangxu Li and Bo Zhao and Guozhen Sun and Zongheng Xue and Yugang Zhao and Zheng Gao and Yaguang Li and Pingran Xiong and Hao Guo and Liepeng Sun and Guirong Huang and Zhijun Wang and Junhui Zhang and Teng Tan and Hongwei Zhao and Wenlong Zhan},
journal= {arXiv preprint arXiv:2404.09187},
year = {2024}
}