Abstract
Dynamics of space charge beam has been investigated in a photo-cathode superconducting radio frequency electron gun by a marco-particle tracking code, PARMELA. Results have been verified by analytical theory of laser driven rf gun, it agrees well at certain injection phases. The exemplary case of Forschungszentrum Rossendorf 3.5cell superconducting radio frequency photoinjector has been analyzed. A 1.5 cell high duty superconducting radio frequency photoinjector has been designed to meet the requirement of the proposed NSRRC narrow-bandwidth and high power IR FEL; satisfactory beam quality has been obtained. A 1nC, 3 MeV beam with rms normalized emittance at 8 mm-mrad can be achieved by optimizing the RF focusing field near the cathode.