SRF Gun at BNL: First Beam and Other Commissioning Results

The BNL 704 MHz SRF gun for R&D Energy Recovery Linac (ERL) successfully generated the first photoemission beam in November of 2014, with a copper substrate cathode stalk. A new multipacting-free, Tasubstrate cathode stalk was designed, fabricated and demonstrated as truly multipacting free. With this new cathode stalk, the beam commissioning has been continued to bring the beam to dump, which is called Gun-to-dump commissioning. This paper discusses the first beam commissioning, design and commissioning of multipacting-free cathode stalk. ERL commissioning status will be addressed as well.