Sub-micron normalized emittance measurement for a MeV continuous-wave electron gun

Continuous-wave (CW) electron sources with sub-micron normalized emittance are of critical importance for advanced linear accelerator based light sources. The DC-SRF-II gun, designed as such a source, has been newly constructed and brought into operation. To characterize the performance of the gun, we have developed an emittance measurement system based upon single slit scanning method under a dedicated beam diagnostics mode. With this system, the measurement of sub-micron normalized emittance, together with a reconstruction of the phase space distribution, has been achieved with high reproducibility. This paper presents a detailed description of the system.