ON THE CALCULATION OF SPIN-COUPLING FORCES

Calculations are presented which define the optimum geometry for the s pin-coupling experiment (SCE) on STEP. It is shown that the spin sourc e must be composed of two sections in which spin-polarized electrons m ake different contributions to the net magnetization. Design features of the SCE on STEP are reviewed and the projected sensitivity of a con figuration optimized for short-range (1 mm) interactions using a vacuu m gap in the spin source is compared with other experiments.