Primary beam-loading tests on DC–SC photoinjector at Peking University

The DC–SC photoinjector is a compact electron gun integrating a DC pierce gun with a 1.3 GHz 1+1/2 cell superconducting cavity. A test facility of the DC–SC photoinjector had been installed in Peking University and beam-loading tests at 4.4 K have been finished. To date the gradient of 6 MV/m has been achieved. The maximum energy gain is 1.1 MeV at 4.4 K. With average beam current of 270 μA, the measured rms emittance is about 5 mm mrad at the beam energy of 500 keV. In this paper some of the experimental results are summarized.