The waterfall target and the solid target ladder can, by design, both be rotated around the central axis of the scattering chamber and be moved vertically to change the target at the beam position. This is done by a mechanical system schematically shown in Fig. A.1, which consists of step motors and absolute optical encoders whose precision is 0.1 mm and 0.1 degree. For E89003 and E89033 experiments, the rotation motion of the target is not required and thus has been disabled to prevent accidental change of the target orientation.