Incident beam current impact on space-charge retention in electron dynamitron irradiated polymethyl methacrylate oleh Kathryn M. Sturge, Noah Hoppis, Aneesh Anandanatarajan, Ariana M. Bussio, Bryson C. Clifford, Emily H. Frashure, Miriam E. Hiebert, James E. Krutzler, Timothy W. Koeth