Electrostatic separator as a source of low energy protons (32 keV – 400 keV) on Van de Graaff accelerator

Abstract

IEAP of CTU operates a Van de Graaff accelerator (VDG) that provides protons and light positively charged particles with energy in the range 0.3 MeV/u–2.3 MeV/u. The purpose of this article is to describe the electrostatic separator that enables to obtain protons with the energy lower than 0.3 MeV. We let the beam of protons with the energy 1.0 MeV impact to tungsten target. The Rutherford scattering take place on the target, scattered protons then enter the electrostatic separator. Applying different high voltage between quarter-circular electrodes of the separator, we selected the energy of protons that pass the separator. We used the electrostatic separation because the control over the high voltage is simple and efficient. For the measurement of proton energy, we used the Silicon Surface Barrier Detector Ortec. We proved that the electrostatic separator can provide protons with adjustable energy from 32 keV to 400 keV, FWHM is in the range 13 keV–19 keV. The separator extends possibilities of the VDG usage. In our further research, we intend to focus on investigation of the profile of the beam getting out of the separator using a pixel detector to obtain information on 3D distribution of the beam energy.