Abstract: A particle accelerator (10) is disposed between a first shielded processing chamber (12)and a second shielded processing chamber (14). The accelerator selectively feeds a higher energy (e.g., 10 MeV) electron beam to the first processing chamber and selectively feeds a lower energy (e.g., 5 MeV) electron beam to the second processing chamber. A conveying system (16) transports article carriers to and through the first processing chamber. At a processing table (18), the articles are conveyed at a closely controlled speed through the electron beam for uniform dosing of an article to be irradiated. A loading station (20) and an unloading station (22) supply and remove articles from the first processing chamber. Beam bending magnets (44) change the direction of an electron beam between the first processing chamber and the second processing chamber.