We outline the scientific motivation for reducing the systematics in the image sensors used in the LSST. Some examples are described, leading to lab investigations. The CCD250 (Teledyne-e2v) and STA3900 Imaging Technology Laboratory (ITL) charge-coupled devices (CCDs) used in Rubin Observatory’s LSSTCam are tested under realistic LSST f/1.2 optical beam in a lab setup. In the past, this facility has been used to characterize these CCDs, exploring the systematic errors due to charge transport. Now, this facility is being used to optimize the clocking scheme and voltages. The effect of different clocking schemes on the on-chip systematics such as non-linear crosstalk, noise, persistence, and photon transfer is explored. The goal is to converge on an optimal configuration for the LSSTCam CCDs, which minimizes resulting dark energy science systematics.