Advances in photoinjector technology have given rise to applications such as XFELs, UED, and UEM. Brighter electron beams from the source increase pulse energies and photon lasing energies for XFELs, as well as an increase in coherence lengths at femtosecond timescales on the Ultrafast Electron technologies. Deeper investigations of the photoemission process have placed stringent requirements on electron sources for next generation electron accelerator technology, and certain novel photocathode sources have been identified as candidates to satisfy these required specifications. At Arizona State University, a cryogenically cooled 200 kV DC electron gun and accompanying photocathode diagnostics beamline was developed and conditioned specifically to implement these novel photocathodes and provide diagnostics for their performance.