After a second photocathode of CsK2Sb with QE=6.5% was produced a month ago, it was transferred from the molecular beam epitaxy chamber to the photogun last week. Preliminary beam test was performed at limited high voltage (200 kV), to avoid any potential issue with field emission. Beam was seen on a YAG viewer, initial beam tuning and profile measurements were done.

The next day, a beam of 2.5 mA was measured in the Faraday cup with a laser power intentionally limited. It will be progressively increased in the coming days/weeks. After curing present HV limitations, commissioning will start to characterize the beam, increase its intensity to investigate charge and lifetime.

Under these conditions (limited HV and beam power), the system was proven to be fully operational and bodes well for future operation, including successful operation of the HV system using N2 only in the tanks.

For this work, performed within a collaboration agreement with RI Research Instruments, we wish to thank the teams of IJCLab and LPSC, who have done an amazing job for the past 3 years.