Commissioning the photocathode radio frequency gun: a candidate electron source for Hefei Advanced Light Facility

The Hefei Advanced Light Facility (HALF) proposed by the National Synchrotron Radiation Laboratory (NSRL) is a diffraction-limited storage ring (DLSR), which plans to use a full energy linac as the injector. To ensure injection efficiency, the injection beam needs to have low emittance. Therefore, a photocathode radio frequency (RF) gun was developed in the HALF R&D project. The gun is designed to deliver high-quality electron bunches with a typically 0.5 nC charge and similar to 4.5 MeV energy with low emittance. The initial system commission with an electron beam was completed at the end of 2020, and a stable 1.2-1.4 mm . mrad emittance with a bunch charge of 500 pC was demonstrated. In this paper, we report the experimental results and experience obtained during the commission, including the RF gun, drive laser system, and beam diagnostics.

Automated summary

The Hefei Advanced Light Facility (HALF) has achieved successful injection of high-quality electron bunches with low emittance through the development of photocathode radio frequency (RF) gun, providing a reliable foundation for the operation of the storage ring.