Proton radiography of a laser-driven implosion by MacKinnon, A, Patel, P, Borghesi, M, Clarke, R, Freeman, R, Habara, H, Hatchett, S, Hey, D, Hicks, D, Kar, S, Key, M, King, J, Lancaster, K, Neely, D, Nikkro, A, Norreys, P, Notley, M, Phillips, T, Romagnani, L, Snavely, R, Stephens, R, Town, R