The external time-of-flight wall for CEE experiment Botan Wang, Haoqian Xu, Xiaolong Chen, Yi Wang, Dong Han, Lei Zhao and Baohong Guo Eur. Phys. J. C, 83 9 (2023) 817 Published online: 13 September 2023 DOI: 10.1140/epjc/s10052-023-11806-2