alternating current beamline bremsstrahlung cancer centripetal force charged particle criticality accident cyclotron radiation electrode electron cyclotron resonance ernest lawrence gyrotron ion cyclotron resonance isochronous cyclotron klystron lawrence hall of science lorentz factor magnetic field magnetic pole natural units nuclear physics particle accelerator positron potential difference proton therapy radiation poisoning right-hand rule rutgers university spiral storage ring strong focusing synchrocyclotron synchrotron triumf vacuum chamber voltage