The ion optics system of the commercially available HF-plasma secondary neutral mass spectrometry apparatus INA3 was found to enable ion energy spectroscopy with good performance : for sufficiently high (2 keV) primary ion energies, the energy distributions of postionized Cu, Al, and Mo atoms almost show the theoretically expected behavior up to 300 eV. Maxima are found at the energies expected from collision cascade emissions. Since ionization occurs on a plasma potential between +35 and 40 V, all ion energies are shifted accordingly. Tuning of the ion optics was accomplished in the secondary ion mass spectroscopy mode by using a sputtered H3BO3/Cu powder pellet as a B+ and BO2- ion source.