Photo-enhanced O â' , H â' and Br â' ion production in caesium sputter negative ion sourceâ€"no evidence for resonant ion pair production. - Hossain, A; Tarvainen, O; Reponen, M; Kronholm, R; Julin, J; Kalvas, T; Toivanen, V; KivekĂ¤s, M; Laitinen, M (Journal of Physics D: Applied Physics, 2022)