SLS-2 - the upgrade of the Swiss Light Source.

An upgrade of the Swiss Light Source (SLS) is planned for 2021-2024 and includes the exchange of the existing storage ring by a new one providing about 40-50 times lower emittance in user operation mode. This will extend the performance of SLS in particular in the fields of coherent imaging, full-field tomography, soft X-ray angle-resolved photoelectron spectroscopy and resonant inelastic X-ray scattering. A science case and a conceptual design for the machine have been established.

Laser-photofield emission from needle cathodes for low-emittance electron beams.

Illumination of a ZrC needle with short laser pulses (16 ps, 266 nm) while high voltage pulses (-60 kV, 2 ns, 30 Hz) are applied, produces photo-field emitted electron bunches. The electric field is high and varies rapidly over the needle surface so that quantum efficiency (QE) near the apex can be much higher than for a flat photocathode due to the Schottky effect. Up to 150 pC (2.