Аннотация:In this paper, we present a new class of a hybrid pho-toinjector in C-Band. This project is the effort result ofa UCLA/Sapienza/INFN-LNF/RadiaBeam collaboration.This device is an integrated structure consisting of an initialstanding-wave 2.5-cell gun connected to a traveling-wavesection at the input coupler. Such a scheme nearly avoidspower reflection back to the klystron, removing the need fora high-power circulator. It also introduces strong velocitybunching due to a 90° phase shift in the accelerating field. Arelatively high cathode electric field of 120 MV/m producesa 4 MeV beam with∼20 MW input RF power in a smallfoot-print. The beam transverse dynamics are controlledwith a∼0.27 T focusing solenoid. We show the simula-tion results of the RF/magnetic design and the optimizedbeam dynamics that shows 6D phase space compensationat 250 pC. Proper beam shaping at the cathode yields a0.5 mm-mrad transverse emittance. A beam waist occurssimultaneously with a longitudinal focus of < 400 fs rmsand peak current >600 A. We discuss application of this in-jector to an Inverse-Compton Scattering system and presentcorresponding start-to-end beam dynamics simulations.