Counter-facing plasma guns for efficient extreme ultra-violet plasma light sourceYusuke Kuroda, Akiko Yamamoto, Hajime Kuwabara, Mitsuo Nakajima, Tohru Kawamura and Kazuhiko HoriokaEPJ Web of Conferences, 59 (2013) 18006DOI: https://doi.org/10.1051/epjconf/20135918006