Abstract: An accelerator for heavy ions includes four uniformly spaced, perpendicular electrodes with a height H, a length L, and a thickness t and wherein each electrode including at least two rectangular windows therein. Each window has a height b and a width W. The windows in each electrode are separated by a distance a and windows of adjacent electrodes are offset by a distance (W+a)/2 from each other. The accelerator is capable of resonating at relatively low frequencies and with relatively small diameters due to the enhanced coupling between chambers in the resonant cavity.