Modernization of the Ion-Optical System of the VITA Accelerator

The work considers the mode of “soft” input of an ion beam into an accelerator, in which an electrostatic Q-snout lens (preaccelerating electrode) is used. Analytical and numerical calculations of the trajectories, phase portrait, and emittance of proton and deuteron beams were carried out in the energy range 0.2–2.3 MeV. It is shown that the use of a preaccelerating electrostatic lens allows one to avoid refocusing of the beam by the strong input lens of the accelerator and improve its passage through the ion-optical path. In this focusing mode, the phase portrait of the proton beam is less sensitive to changes in current and ion energy, which is important for medical installations and for its use in other applications.