Abstract <p>The basis of the neutron generator is a miniature linear accelerator, which allows us to obtain a specific size of the generating region of neutron radiation with specified parameters of the neutron flux. Numerical modeling can help solve the problem of creating an accelerator with a strictly specified ion beam size on a target. Based on the simulation result, it will be possible to select the appropriate optimal physical and geometric characteristics of the Penning ion source and the ion-optical system. The initial data for the simulation are the spatial and energy distributions of ions emitted from the ion source. The purpose of the study was to experimentally determine these characteristics. The energy spectra and spatial distributions of ions are given for various discharge combustion modes as functions of the working gas pressure and the voltage at the anode. The relationship between the discharge VAC and the sagging potential inside the discharge, as well as their effect on the plasma emission boundary, is shown. Data on the width of ion beams and energy spectra at half-height are presented. The maximum value of the energy spectra is two and more times less than the corresponding value of the voltage applied to the anode. The gas pressure had little effect on the shape of the energy spectra. The profiles of the ion beams differed during probe diagnostics of the ion source in two perpendicular planes.</p>