Static beam position monitor for a small ion storage ring S-LSR

The static beam position monitors for a small ion storage ring S-LSR are being developed now. The monitors are installed at the chamber for a bending magnet because of the limited available space. The monitor is composed of four electrodes whose shape is a right triangle and dimension is 100[mm] x 200[mm]. The shape of the monitor aperture is octagon, and the distance between upper electrodes and lower electrodes is 46 ± 0.3[mm]. The position information of the monitors is calibrated with a test chamber. Two methods for position identification are proposed. One is Difference over Sum method, another is Log Ratio method. The linearity about ± 50[mm] was realized by the latter signal identification method. This region is the full length of the monitor electrode. (author)