Simulation study of positron production by picosecond laser-driven electrons Yonghong Yan, Yuchi Wu, Xiaohui Zhang, Minghai Yu, Tiankui Zhang, Bin Zhu, Fang Tan, Yue Yang, Wei Fan, Feng Lu et al. (4 more) Eur. Phys. J. D, 73 9 (2019) 193 Published online: 03 September 2019 DOI: 10.1140/epjd/e2019-90394-7