Belomestnykh, S.A. Ben-Zvi, I. Brutus, J.C. Hayes, T. Litvinenko, V. Mernick, K. Narayan, G. Orfin, P. Pinayev, I. Rao, T. Severino, F. Skaritka, J. Smith, K.S. Than, R. Tuozzolo, J.E. Wang, E. Wu, Q. Xiao, B. P. Xin, T. Zaltsman, A. JACoW Geneva, Switzerland 978-3-95450-178-6 10.18429/JACoW-SRF2015-THPB058 English 1240-1242 THPB058 gun cathode SRF electron laser Contribution to a conference proceedings 2015 2015-12 http://dx.doi.org/10.18429/JACoW-SRF2015-THPB058 http://srf2015.vrws.de/papers/thpb058.pdf A 112 MHz superconducting RF photoemission gun was designed, fabricated and installed in RHIC for the Coherent electron Cooling Proof-of-Principle (CeC PoP) experiment at BNL. The gun was commissioned first without beam. This was followed by generating the first photoemission beam from a multi-alkali cathode. The paper presents the commissioning results.