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Cs2Te photocathode

The high-field (> 80 MV/m) photoinjector has a large area, high quantum efficiency Cs2Te photocathode (diameter > 30 mm).

The photocathode, a crucial component of the upgraded facility, is fabricated on-site. The RF gun generates high-charge, short-pulse, single bunches (Q > 100 nC) and long bunch-trains (Q > 600 nC) for wakefield experiments. Quantum efficiency (QE) measurements indicate long, stable photocathode lifetime under demanding conditions ― the QE of Cs2Te cathode is typically near 3% for several years. The Cs2Te photocathode has only been changed once since coming online in 2014.