Error analysis for pepperpot emittance measurements redux: Correlated phase spaces

Recently, Jolly et al. presented an analysis of the rms emittance measurement errors from a first principles approach [1]. Their approach demonstrated the propagation of errors in the single-plane rms emittance determination from several instrument and beam related sources. We have extended the analysis of error propagation and estimation to the fully correlated 4-D phase space emittances obtained from pepperpot measurements. We present the calculation of the variances using a Cholesky decomposition approach. Pepperpot data from recent experiments on the NDCX-II beamline are described, and estimates of the emittances and measurement errors for the 4-D as well as the projected rms emittances in this coupled system are presented.