Design of Ion Beam Electrostatic Modulation System

This article is devoted to a stage of pulsed proton injector development which is conducted at the Gaponov-Grekhov Institute of Applied Physics, Russian Academy of Sciences. The result of electrostatic chopper numerical modeling is presented. It is a part of proton injector for linear accelerator of compact neutron source DARIA. A continuous wave mode gasdynamic electron cyclotron resonance ion source GISMO is used as an injector. The ion source has high volumetric energy input into plasma due to the use of “technological” gyrotron radiation to maintain and heat the plasma. The optimal geometric parameters (deflecting plates size and distance between them) of electrostatic chopper are determined during the calculations of proton beam propagation through the injector. The minimal voltage, which is enough for full beam deflection without losses inside chopper, is achieved at the optimal chopper geometry. Also, the output beam current dependence on chopper plate voltage is studied. The calculations allow for determining temporal characteristics of pulsed proton beam which escapes the injector at known pulse parameters of chopper voltage supply source.