  Electro-optical testing and characterization of the Vera C. Rubin Observatory
Legacy Survey of Space and Time (LSST) Camera focal plane, consisting of 205
charge-coupled devices (CCDs) arranged into 21 stand-alone Raft Tower Modules
(RTMs) and 4 Corner Raft Tower Modules (CRTMs), is currently being performed at
the SLAC National Accelerator Laboratory. Testing of the camera sensors is
performed using a set of custom-built optical projectors, designed to
illuminate the full focal plane or specific regions of the focal plane with a
series of light illumination patterns: the crosstalk projector, the flat
illuminator projector, and the spot grid projector. In addition to measurements
of crosstalk, linearity and full well, the ability to project
realistically-sized sources, using the spot grid projector, makes possible
unique measurements of instrumental signatures such as deferred charge
distortions, astrometric shifts due to sensor effects, and the brighter-fatter
effect, prior to camera first light. Here we present the optical projector
designs and usage, the electro-optical measurements and how these results have
been used in testing and improving the LSST Camera instrumental signature
removal algorithms.
