A mass spectrometry system arrangement includes a curved ion guide, where the curve of the ion guide is positioned such that a portion of the ion optics are visible from at the ion guide entrance, e.g. line of sight or z-axis. There are four electrodes parallel with each other and the central curved axis. Each electrode is equally radially spaced from the curved central axis. For each cross section of the ion guide, the central curved axis being positioned at the origin, the curved electrodes being radially positioned at 45°, 135°, 225°, and 315°. Depending upon the system, a blocking device is positioned external to the ion guide but within the “line of sight” or positioned tangential to the rising section of the bent ion guide.