[en] Electrostatic field calculations and experimental results have shown that the energy level (keV-MeV) of an existing linear or circular accelerator can be upgraded 15-30% by increasing the insulating strength of the electrostatic column. Higher value of field gradients between the accelerator electrodes, thereby insulating strength, without affecting the high voltage insulation of the total system can be achieved by using an optimum electrode-insulator design glow discharge conditioning, and increasing system pressure