Successful user operation of a superconducting radio-frequency photoelectron gun with Mg cathodes

Review of photocathodes for electron beam sources in particle accelerators

“…Mg can provide a QE of about 0.2% when illuminated with 258 nm UV light after a proper cleaning process. 29 Another advantage is that the preparation of such metal photocathodes is less complex compared to the preparation of semiconductor photocathodes, which is further described in the following sections.…”

“…In the non-contact mode, the biggest advantage is that the cathode can be operated at temperatures different from the cavity temperature. 29…”

Conceptual Project of the NSC Kipt Nuclear Physics Complex for Basic and Applied Research in the Field of Nuclear Physics, High Energy Physics and Interaction of Radiation With Substance

“…Several types of injectors have been developed and debugged, which make it possible to obtain an average current value of more than 1 mA or a charge in a bunch of more than 300 pC [11,[17][18][19][20][21]. The maximum electron energy is 9.5 MeV [11].…”

Electron Sources for Accelerators

“…Another reason for concern is contaminating the cavity with particulates during cathode insertion and from the photocathode itself when subject to high gradient during operation. The past decade has seen tremendous advances in SRF guns technologies [57], from proof of principle using Pb films on the back wall of the Nb cavity [58], to the routine use of normal conducting metal and semiconductor photocathodes for user-based accelerators at HZDR [59,60], and for the Coherent Electron Cooling (CeC) proof of principle project at BNL [61]. These two SRF guns represent the state-of-the-art, demonstrating that both metal and semiconductor photocathodes (cold or warm) can be safely operated to routinely deliver beam.…”