Performance of the LHCb RICH photo-detectors and readout in a system test using charged particles from a 25 ns-structured beam by Adinolfi, M, Albrecht, E, D'Ambrosio, C, Gys, T, Morant, J, Piedigrossi, D, Patel, M, Wyllie, K, Ameri, M, Fontanelli, F, Mini, G, Sannino, M, Arnaboldi, C, Bellunato, T, Fanchini, E, Perego, D, Pessina, G, Barham, C, Buszello, C, Dickens, J, Gibson, V, Jones, C, Kerzel, U, Rogers, G, Skottowe, H