Xiang, R. Adolphsen, C. Arnold, A. Gatzmaga, S. Hartung, W. Hoffmann, A. Kelly, M.P. Kim, S.H. Konomi, T.K. Lewellen, J.W. Miller, S.J. Murcek, P. Petersen, T.B. Popielarski, L. Saito, K. Smedley, J. Steinbrück, R. Teichert, J. Xu, T. JACoW Publishing Geneva, Switzerland 2673-5504 978-3-95450-234-9 10.18429/JACoW-SRF2023-MOPMB067 English 267-270 cathode gun SRF insertion operation Contribution to a conference proceedings 2023 2023-09 https://doi.org/10.18429/JACoW-SRF2023-MOPMB067 https://jacow.org/srf2023/papers/mopmb067.pdf Superconducting radio frequency photo injectors (SRF gun) offer advantages for operating in continuous wave (CW) mode and generating high-brightness and high-current beams. A new SRF gun is designed as a low emittance photo injector for LCLS-II-HE and a prototype gun is currently being developed under collaboration between SLAC, FRIB, HZDR and ANL. The aim is to demonstrate stable CW operation at a cathode gradient of 30 MV/m. One of the crucial component for successful SRF gun operation is the photocathode system. The new SRF gun will adopt the HZDR-type cathode, which includes a cathode holder fixture (cathode stalk) developed by FRIB and a sophisticated cathode exchange system designed by HZDR. This innovative cathode insertion system ensures accurate, particle-free and warm cathode exchanges. A novel alignment process targets the cathode to the stalk axis without touching cathode plug itself. To commission the prototype gun, metallic cathodes will be used. A specifically designed vacuum system ensures vacuum pressure of 10⁻⁹ mbar for transport of a single cathode from the cleanroom to the gun. Thus maintaining cathode quality.