Experimental benchmarking of nonlinear tune response matrix with several controlled sextupolar errors

The nonlinear tune response matrix (NTRM) method was developed to diagnose the lattice nonlinear components. It explores a nonlinear tune response to a controlled closed orbit deformation (COD). In this paper we consolidate the applicability conditions of the NTRM and prove that it can be experimentally applied to reconstruct many nonlinear errors. We experimentally validate this approach by reconstructing six tiny controlled sextupolar errors.