Horizontal-vertical coupling correction at Aladdin

Horizontal-vertical coupling and vertical dispersion can arise from vertical misalignments and tilts of bending magnets, quadrupoles, and sextupoles. Experimental measurements and accelerator code studies suggest that the vertical dispersion from bending magnet errors and quadrupole height errors is largely compensated by optimization of the vertical closed orbit. The majority of the coupling and vertical dispersion remaining after orbit optimization may be the result of quadrupole tilts on the order of 1-2 mrad. A correction scheme is being implemented in which the excitation of skew-quadrupole correctors is determined from measurements of the vertical orbit displacements resulting from horizontal steering bumps and vertical dispersion